Caravan gas water heater

Caravan gas water heater

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A caravan gas water heater provides essential hot water to ensure your caravan or “home from home” has the warm water system to ensure you can shower, at the correct water temperature, and more importantly at the correct hot water flow rate.There’s nothing worse than a poor showering experience as you enjoy your stay in your caravan or holiday home. The other main purpose of caravan water heaters is to provide adequate hot water for dishes or washing up – an area which many of the low-quality water heaters struggle to achieve (more on this further down the page)

Water heaters

Firstly, we have to define what a caravan water heater is – the device, heats the domestic hot water up to temperature for such uses as showering, bathing or for the sinks, whether it be hand wash sinks or kitchen sinks – this is referred to as sanitary water or domestic hot water – DHW for short.

So, the water heater, has to cover the water hot demand for your caravan – Here are some figures and numbers that your water heater has to cover –

A standard showerhead flow rate is 7 or 8 Litres a minute – and the standard temperature is 40 Degrees C

Sink taps – 4 litres per minute capacity– standard type

Cloakroom or basin “spray type taps” – 2 litres per minute capacity- again at 40 C temperature

Bath mixer taps – modern bath taps have an approximate operating demand rate of 12 Litres per minute capacity-  at 40 Degree C.

Kitchen sink taps – 4 to 6 litres per minute but at a heated temperature of 50 Degrees C

Because 50 Degrees C is the temperature required to effectively remove grease from cooking utensils, plates, cups etc.

Thus, it is very important that your caravan water heater can achieve this temperature, with a flow rate to fill the washing up sink in a reasonable time.

So the water heating range, power or capability of your caravan water heater needs to be suitable to the demands required of it.

Caravan water heaters

Caravan water heaters come in two main types, electric powered or gas powered

Electric heating element / Electric water heaters

These use electricity to heat the water directly – but come with lots of potential issues that you need to be aware of –

1. The struggle with the capacity to produce warm water instantaneously, as most caravans only have a 1 Phase / 240-Volt electricity power supply – with a maximum draw of 32 Amps – you cannot produce enough thermal energy with an electric caravan water heater to satisfy the large capacity hot water demands such as a shower adequately – You need 7 Litres a minute for a standard shower.

2. Another downside is that electricity energy prices are also the most expensive, especially when compared to gas or more specifically LPG (propane) that is the fuel of choice for static caravans.

3. There are electric powered water heaters for boats, or a motor home, that also include a hot air heater – but these only have a 5 Litre capacity, and take approximately 50 minutes to heat this volume of water from 15C to 60C – which is only enough water for a sink, and nowhere near enough for showering etc. This is a specialist market, and the truma therme / truma heaters compact heater is the unit you want for vehicle or boat installation.

Gas water heater for caravan

Gas caravan water heaters make up the largest part of the requirements for caravan water heaters, as they provide many benefits such as the capacity to provide many litres of heated hot water, as well as fast heating of the water system to an accurate water temperature. They are highly efficient, which saves you money and more importantly work correctly.

The most popular are –

lpg water heater for caravan

With LPG gas being the predominant gas used on caravan and holiday home parks, where static caravans or static holiday homes are located, this has resulted in LPG or Propane gas water heaters being the most popular water heater for this sector.

The LPG caravan water heaters that we offer are of the highest quality , and heat the water in the most efficient manner and work correctly, our most popluar unit is the SFK water heater, which is equipped with a cravan water heaters class leading 16mm diameter heat exchanger water ways, which ensures very low pressure drops, guarantees lower risk of clogging, greater thermal efficiency, and greater ease of cleaning. – which is especially important in areas with hard water.Just double check the following map of the UK and Northern Ireland.

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Hard water areas of the UK, Northern Ireland and Southern Ireland

LPG Gas (Liquefied Petroleum Gas)

LPG gas or Propane gas as its also known, is the perfect gas to use for caravan water heaters, as the gas is readily available and very common in the UK- other many benefits of the gas are; –

  • LPG gas is easy to transport
  • The gas is clean burning – the burners have a longer life; hence maintenance is lower.
  • An effective and efficient gas with direct firing systems as the heat loss is minimal.
  • LPG gas is easy to store, in cylinders or a bulk tank – No spillage risk as opposed to oil for example.
  • Propane gas has a low boiling temperature of minus 42ºC, making it perfect fuel for use in lower temperatures and well suited to power a heating boiler or water heater for caravans.
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Lpg gas cylinders feeding a static caravan

They can be hidden away from sight like so

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Caravan water heater gas fired

The most popular water heater we do for static caravans is our SF14 model, which has a 24kW output, and is available not only in LPG, but also natural gas if so required. This instantaneous domestic hot water heater produces hot water on demand.

The dimensional details are –

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SF14 LPG water heater from Flexiheat UK


Hydraulic connections – at the bottom of the water heater

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Aesthetically pleasing design

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SF14 Low Nox from Flexiheat UK

Advantages of our caravan water heaters

  • Copper wet chamber heat exchanger that prevents thermal inertia
  • Reduction of initial water over temperature with low flow rates
  • 16mm diameter heat exchanger water ways
  • Room sealed lpg water heater
  • Electrical protection level is IPX4D
  • Ease of access for maintenance / servicing

caravan water heaters; stock add; boiler; water system;

  • Possibility of remote shutdown with our internet / Wi-Fi enabled controllers

Caravan Water Heater Performance

Simply said, the volume of hot water generated by any hot water heater is exactly proportional to the temperature rise of the hot water required. As an example, consider the following:

Showering temperature is 40 Degrees C –

Dish / Kitchen Water is 50 Degrees C – to ensure grease is removed from the utensils

Here is some data on the temperature of the mains cold water in the UK, at different times of the year

mains cold water temperature for the UK

Mains cold water inlet temperatures for the UK by region Source – Energy Saving Trust – 2008

So, the required water temperature rise, is known as “Delta T “- this is abbreviated as this sign “ΔT” – And ultimately the lower the temperature rise, the more warm water the device will produce – In the summer when the incoming water is warmer – it will produce more litres, and in the winter, when the incoming water is lower, it will produce less – it’s a simple as that.

Here’s our performance data of our SF14 water heater, at various temperature rises.

flow rates; boiler;

Thus, to achieve 40C warm water in the summer, for the majority of the UK, you need a Delta T of 20C – thus our unit produce 15.82 Litres/min – enough to run a bath or 2 showering heads at the same time.

And more importantly, for people who inhabit a static caravan in the winter months – when the delta T is 30C – then you have 10.82 Litres/min – again more than enough to run a standard showering head (which is 7/8 Litres /min) – So we have you covered when you need warm water the most – in the winter!

Caravan Gas Fired Water Heater

We carry stock, and use a small pallet service to deliver anywhere in UK, Northern Ireland and Southern Ireland.

Should you require any more information or prices on the best caravan gas water heater / lpg water heater for caravan, then give our sales team a call on 01202 822221.A full VAT invoice is supplied for all items supplied.

LPG Combi Boilers for Caravans

LPG Combi Boilers for Caravans

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Best lpg combi boiler for a static caravan from Flexiheat UK

Propane or LPG combi boilers when installed in static caravans, are considered to be the “ideal boilers” for satisfying the central heating system (radiators or underfloor heating) and the domestic water heating.

They offer a more powerful and more efficient heating system for their size and will run at a lower cost to the static caravan owner or user.

They are in essence a lpg heating system boiler and static caravan water heater in one combined unit – so there’s no need for lpg heating boiler and a lpg water heaters as two separate appliances these days – a compact lpg combi boiler

LPG is a popular alternative to standard mains gas or oil-based heating systems as it’s safe and efficient and it’s easy to get connected today. LPG is an effective way for caravan owners to heat and provide hot water for their static caravan, as it’s clean, safe and smokeless.

liquid petroleum gas or LPG as we know it in the UK, is the most commonly used fuel for static caravan boilers for the UK and Ireland, as lots of caravan parks or sites are off the mains gas grid.

LPG boilers are a great alternative to electric heating systems. They are very cheap to run and easy to install. One type in particular, called a lpg or propane combi boiler, is very popular with caravan owners because its low cost of running and maintenance. Most lpg combination boilers are very compact, and can be installed in any static caravan. They can also be installed in a holiday home,chalets, holiday flats and apartments, so you do not have to live in a caravan to use a lpg combination boiler.

Best LPG Combi Boiler ?

When looking for a new lpg boiler or lpg combi boiler for a static caravan, there are a two main parts to a lpg combi boiler that we need to look at – the central heating side of the boiler for the static caravan and the lpg water heater side of the unit, as well as high efficiency, to ensure your gas bills are as low as possible for your static caravan.

You’re also looking for a compact lpg combi boiler, as static caravans aren’t always necessarily the roomiest of places, a lpg combi boiler that is small, yet powerful enough to do the water heater demands as well as the central heating system is a benefit.

static caravan boiler; static caravan boiler combi; refill;shop

Dimensions of our combination caravan boiler – R2C 24kW from Flexiheat UK



The primary compact lpg combi boiler for static caravans is a condensing boiler, as these use the lpg / propane gas to the maximum efficiency, both for the heating and water heater side of the boiler.

Our most popular static caravan boiler is the 24kW model – which will supply heat up to 23.5 kW of heat output / power and will supply your caravan with domestic hot water at a flow rate of 11.5 litres / min at a temperature rise of 30 Degrees C – this is enough to run a bath in the winter period.


We always quote water flow rates at a temperature rise of 30 Degrees – these are winter time performance figures – because we want you to have a hot bath or shower (an average shower uses 7 or 8 litres / minute) when you need it the most.

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Heat exchanger of our caravan combination boiler from Flexiheat UK



The 12mm diameter internal s/s pipe where domestic hot water is produced, is inside the patented main heat exchanger (28mm diameter). Its total length is 8 meters and this ensures a large capacity for hot water production. The hot water flow is always available and always in condensing operation, resulting in lower energy costs and bills.

This class leading technology, with the large diameter, also reduces the chance of scale, something that older technology boiler that use a plate heat exchanger can suffer from. This is incredibly important in hard water areas- as our units don’t suffer from this.

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LPG static caravan combi boiler technical detail

compact lpg combi boiler; caravan boiler;

R2C 24kW Compact lpg combi boiler – Technical data from Flexiheat UK


Download the manual here

R2C 24kW Propane or Natural Gas Combination Boiler for static caravans – Manual

External mounted propane combination option

We also supply an external combi boiler that is weatherproof, this external lpg combi boiler designated the R2K 24 – is a 24kW condensing model, is a little heavier at 37 KG’s – than our internal boiler – thus depending on the weight you caravan wall can take, you can either mount it directly or make a frame from the chassis of the static caravan to support the weight.

external lpg combination boiler; water heater; morco lpg water heaters;

External LPG combination boiler for Static caravans from Flexiheat UK

The benefit of having an external compact lpg boiler, that is fully weatherproofed, is that you eliminate (the gladly rare but often fatal) carbon monoxide poisoning risk.

Our boilers can be converted from an LPG (propane) to a natural gas boiler easily, should the need ever arise. We just supply plumbers with a simple conversion kit, and it’s a 5-minute job to do.

So, if you want supplied a high-quality replacement for your vaillant or morco boilers- call us

LPG Boiler Controls for Static Caravan

You can control your heating system via the inbuilt control panel or even remotely via an app on your phone, tablet or computer (internet access required), so you can control your boiler from anywhere.

Cloud warm controller for R2C 24kW; stock; shop; spares; range; gas; caravan;


lpg boilers


Our standard lpg combi boiler, which is internally fitted within the caravan, requires a flue kit fitted. Our most common flue kit is a co-axial room sealed either horizontal or vertical, which means that all the air for the combustion process is taken from the exterior of the caravan (no windows need to be left open etc)

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Horizontal flue kit for the R2C caravan combination boiler from Flexiheat UK

or Vertical

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lpg water heaters

If you require just a water heater only, then you just require a lpg water heater, and we do a great range that are ideal high efficiency replacements for older Paloma, Vaillant,Worcester Bosch,Saunier Duval, Rinnai or Morco LPG water heaters.

But a few points to be aware here with regards to lpg water heaters –

There are lots of lpg water heaters on the UK market, that we’ll shall say are of “questionable quality “and also, we question some of the “performance claims”

Our top tips for selecting an lpg water heaters are –


1.Select a good quality manufacture for your lpg water heaters

Preferably from Europe, as by law spare parts have to be available for at least 10 years. Spares (including flue components spares) that aren’t available anymore, means a new water heater in most cases, with the additional expense of installing a new water heater.

2.Ask what country the LPG water heater is manufactured in?

Some are buying product in from the far east, and putting a badge on them – most of these are of very questionable quality to say the least – let alone the spares back up / availability.

3.Make sure your lpg water heaters, have suitable ” ErP” labels supplied

These are minimum requirements these days, to be on the UK and European market

The market for LPG water heaters really is really awash with some poor-quality water heaters, and the old adage of ” you get what you pay for ” or “buy cheap buy twice” really applies to the lpg water heaters market in the UK.

If you’re looking to replace the older paloma range , saunier duval,bosch, vaillant,rinnai or worcester models, with a water heater range with a great warranty ,for your static caravan, chalets ,holiday home or even a house , then you need to look at this webpage that is dedicated to our lpg water heaters .

Boiler Installation

Any LPG qualified gas fitters or plumbers can fit our lpg combi boiler, they are an easy installation, just connect up to the static caravans heating system and also to the static caravan water heater system.

As we supply plumbers and gas fitters across the country, it is important to use a relevant gas safe engineer, who is qualified to work on and install a lpg combi boiler in a caravan. Use the following website to check – Gas Safe Register

Delivery / Collect Options

We normally have the units available on a 2/3 working day delivery service or a next working day delivery if so required (at extra charge). Or alternatively you can collect from our site. Just let our sales team know your requirements.

Best static caravan boilers / static caravan gas boilers

For more information on the best lpg combi boiler range for a static caravan, residential park homes, chalets or holiday homes or apartments for sale on the UK market, manufactured in high quality stainless steel, then please give our sales team a call on 01202 822221, or use the web site contact form.


50kw Combi Boiler

50kw combi boiler

50kw combi boiler; 50 kw gas combi boiler;

Our Flexiheat 50kW combi boiler is a well-designed condensing combination boiler with 97% efficiency making this an “A” rated boiler for heating and hot water. Due to this efficiency, it can reduce fuel bills and reduce your carbon footprint as it can generate enough heat to meet the demand of your home using less fuel than an older inefficient boiler. The boilers installation is easy, and we can supply the boiler in either natural gas or LPG (Propane) gas

Combi boilers are one-of-a-kind, compact, and cost-effective solution that are ideal for houses with limited space. They combine a water heater and a central heating boiler into a single device, eliminating the need for additional water cylinders or tanks in your home.

With boilers account for approximately 60% of a household’s yearly energy costs, they have an enormous impact on fuel bills. With more seasoned older gas boilers, a significant sum of heat that may be utilized to produce warming and hot water is wasted, making them progressively costly to run.

Our 50KW combi boiler is more than 97% efficient, so 97p of each £1 you spend on gas for your combi boiler is utilized.When using an Opentherm internet-connected Smart controller, you can control our ERP “A” rated device, on the go from your mobile, or tablet – now becoming a must for people with busy lives.

ErP A-rated for both heating and hot water, this efficient, reliable combi boiler provides effortless comfort at a reduced running cost. All while you sit comfortably in complete peace of mind, knowing that you have a highly efficient 50kw combi boiler, that is also one of the quietest in its class at 52 decibels installed (for comparison a refrigerator is around 50 Decibels).

Key features of our 50kW combi boiler are –


1.Increased power- compared to the competition – we actual make a 50kW combi boiler – that will do 53.85 kW of heating power based on an 50C/30C flow and return system, or 49.19kW at 80C/60C.


2.Fantastic new design – this 50kW combi boiler benefits from aesthetically pleasing looks


3.increased burner modulation ratio of 1:10, which prevents on/off cycling for a lengthy product life.


3.It’s inbuilt intuitive controller, which benefits from an intuitive menu structure for, commissioning, and fault finding if so required, which means no need to search through manuals for fault codes. Resulting in rapid diagnosis of any issues. Not that you’ll use the fault finding much with our quality range of efficient 50kw gas fired combination boilers


4.Servicing – With plenty of room within the appliance casing – this range of 50kW combi boilers is installers dream to work on.


5.Installation of the boiler – which must be done by gas safe qualified installers or company – can be in any location, as we do various flue options, such as a room sealed range (see details below) also being one of the quietest boilers, you’ll have complete peace where ever you locate the boiler.


6.Can be operated on a system pressure of 0.3 to 2.1 Bar for the heating side and 0.5 to 6 Bar system pressure for the Domestic Hot Water side of the appliance


7.This range of combi boiler is suitable for natural gas or LPG (must be specified at date of customers order) – sit comfortably knowing if you change your gas type the boiler is easily converted over.


8.DHW flow rate at a 35 Degrees C temperature rise is 20.30 litres/min or at a 40 Degrees C rise then its 17.5 litres/min. 


Heating system side of the boiler

Central heating output – Based on flow and return temperatures of 80/60 and the fact that current new build homes have radiators that on an average of 1.5kw output the 50kw combi boiler can produce 53.85kw of output power which is enough to heat up to 35 radiators on the system. (Please note: If retrofitting, the number of radiators cannot exceed the out power of the boiler at 53.85kw in total)

Some of our competitors claim a 50 kW combi – but in reality, the heating side of the boiler is only 35 kW of output

There is not may companies producing a 50kw combination boiler, some people may regard a boiler produced by the Worcester Bosch company – namely the worcester greenstar 8000 50kw combi boiler range as a direct competitor to our boiler, but in reality, this boiler, will only produce –

Central heating output (kW) – 33.8 kW at 80/60C or at 50/30C condensing mode – 35.7 kW

While our unit will produce 49.19 kW of heating power at 80/60C or at 50/30C condensing mode – 53.85 kW

Thus, can you really call the worcester greenstar 8000 a 50 kW combi ?? you decide, but it seems a bit short to us?

On the Domestic Hot Water performance –

The worcester greenstar 8000 is 48.9 kW rated on the dhw side, the dhw output is –

Flow at the DHW tap (35°C temperature rise) – 20.3 l/min

Flow at the DHW tap (40°C temperature rise) – 18 l/min

With a plus or minus of 15%  quoted.

Whilst our boiler will produce the following outputs

Flow rate at the DHW tap (35°C temperature rise) – 20  l/min

Flow rate at the DHW tap (40°C temperature rise) – 17.5 l/min

There’s no plus or minus 15% for our data – we will produce those figures quoted above

Domestic hot Water performance

Due to its excellent domestic hot water flow rate, with a temperature rise of 30 degrees C @ 23.40 ltrs/min of hot water flow or with a temperature rise of 35 degrees C @ 20 ltrs/min, the 50kW combi boiler is ideal for a two-bathroom house.


Heat Exchanger

These devices are equipped with a stainless-steel exchanger with a large Ø 28mm monotube coils, which not only benefits from very low pressure drops, but guarantees lower risk of clogging, with greater thermal efficiency, and greater ease of cleaning. We guaranteed the heat exchanger for 10 years, when a good quality magnetic dirt and air separator is fitted to the system, and the devices is serviced annually.

Technical Data




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Download the 50kW Combi Boiler Manual Flexiheat UK

Boiler Flue Options

We do various flue options, the most common is a co-axial, which takes the combustion air from outside, and the combustion gases from the device to the outside – making these combi units room sealed when used.

The most common flue kit is our horizontal co-axial kit – both of these can be used up to 10 metres in length

Horizontal flue kit from flexiheat UK;worcester greenstar 8000;ex vat;worcester bosch;ex vat;worcester bosch;ex vat;inc vat;quietest boilers;inc vat;ex vat

Horizontal kit from Flexiheat UK


Or the vertical option

Vertical flue kit from Flexiheat UK;ex vat;worcester bosch;worcester greenstar 8000;ex vat;worcester bosch;ex vat;worcester bosch

Vertical kit from Flexiheat UK


Both of these can be used up to 10 metres in length, losing 0.8 metres off the length for every 90° elbow used, and 0.5 metres for every 45° elbow used from the overall distance.

Or by using a split system, we can achieve routes of up to 60 metres

boiler Split flue pipe system;

Split pipe system from Flexiheat UK

Boiler controls

With an easy-to-use display with an intuitive menu structure and greater connectivity with any Opentherm compatible controller, our 50kw combi or combination boiler is made to suit your lifestyle, as well as your home.

One of the new features of OpenTherm – (which is a standard communication system that connects natural gas, lpg gas, oil or even electric boilers with room thermostats). This means that your combi boiler can be used with any OpenTherm compatible thermostats or controllers – the best-known brand on the UK market to date is between Nest or Hive, but we also provide a solution from stock, which has extended range, and key features such as the ability to control your boiler from a mobile phone, pad or your computer.

This means if your away on from home, you can have controllers that will activate your boiler based on your postcode location in relation to your property – so it’s nice and warm when you get in or should you be travelling, you can adjust the boiler start time in relation to when your due home on your phone or other device, should you be delayed for any reason you simply adjust the time on your device.

Class 5 modulating controls, can provide an increase of 3% system efficiency, as they have a direct impact on the efficiency of the modulating combi boiler, by modulating the flow temperature in line with the internal temperature of the property.

Easy Remote

Advanced class 5 remote control, which performs the dual function of a thermostat and remote control of the boiler. This controller must be wired from its location to the appliance

Easy remote controller from Flexiheat UK; Class 5 modulating boiler controller range;bosch easycontrol;stock;website;inc vat;delivery;stock;England;delivery;intelligent filling system;worcester greenstar 8000:stock;inc vat

Easy remote controller – Wired – from Flexiheat UK

  • Daily / weekly heating and DHW programming;
  • Heating system and DHW temperature setting;
  • Reset by remote control in the presence of resettable fault codes;
  • Thermoregulation management;
  • Appliance parameter programming (technician level)


Cloud Warm WIFI (Wireless) Controller

A free-standing class 5 advanced remote control thanks to the free downloadable app which performs the dual function of chrono thermostat and remote control of the device from a mobile phone or tablet.

Cloud Warm Wired controller from Flexiheat UK; stock;delivery;stock;website;inc vat;stock;delivery;stock;worcester greenstar 8000;ex vat

Cloud Warm Wired controller from Flexiheat UK


  • Daily / weekly heating and DHW programming;
  • Cloudwarm application available for free on the Apple Store and Google Play; No annual charges to pay
  • Heating and DHW temperature setting;
  • Push notifications to a mobile device in the presence of any abnormality or fault;
  • Reset from a mobile device in the presence of resettable fault codes;
  • Thermoregulation management;

Cloud Warm WIFI (Wired)

As above functions, but this unit must be wired back to the 50kw combi boiler
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Cloud Warm Wireless Opentherm controller from Flexiheat UK



Brand and Quality manufacturing

Our 50kw combi boiler is manufactured in accordance with ISO 9001 and ISO 1400 certified management systems and testing techniques. Should you require more information, prices or delivery times, then please contact our sales teams for the best 50kw gas combi boiler on the UK and Irish market. You can call our office on 01202 822221 or send an email via our contact form.

LPG Water Heaters

LPG Water Heaters

Lpg Water heaters; lpg instant water heaters; lpg tankless water heaters;

LPG (Propane) Water Heaters from Flexiheat UK

LPG gas water heaters– What are they, and what are the benefits? An LPG (Liquefied Petroleum Gas) water heater is a gas fired water heater that heats domestic hot water instantaneously to multiple points around your home or building. These lpg water heaters allow you to connect the water heater to a number of hot water outlets throughout your property or home or even a commercial building.

On demand or continuous flow propane gas water heater?

This type of lpg water heater, provides a simple and proven solution for providing instantaneous domestic hot water on demand, without the need of an indirect cylinder and a propane gas boiler. This liquefied petroleum (LPG for short) gas fired water heaters, which are available in propane (LPG) or as a natural gas water heater are simple, with high energy efficiency and clean combustion.These units when powered by propane are often called lpg tankless water heaters provide many benefits being far more energy efficient that storage units.

They are also an energy saving solution to more traditional domestic hot water storage systems, as they only heat the water when its required. These facts have made the lpg flow water heaters not only the customers propane water heater of choice, with great user comfort, but also the plumbers / heating installers choice as well.

Propane Water Heater? What are the benefits

  • High performance mains water pressure to all warm water outlets
  • ErP Class “A” energy efficiency for your domestic hot water requirements – Save money and save the environment.
  • LPG tankless heaters -no cylinder required -Tankless lpg water heater systems are far more efficient than storage cylinders and boilers.
  • Low NOx or condensing LPG fired water heater – less polluting and better for the environment
  • High hot water flow rates of up to 29 litres per minute with a water temperature rise of 33 Degrees C
  • We can supply Propane gas or Natural gas fired versions.
  • Internal ( indoor ) and externally ( outdoor ) mounted products are availableExternal gas water heater; outside gas water heater;external lpg water heater

External or outside gas water heater from Flexiheat UK

  • Modular – Flexibility of usage – multiple heaters can be used to supply greater hot water demands, in cascade.
  • These propane water heaters are suitable for domestic and commercial applications such as domestic properties, cafes, pubs, restaurants, offices or shops
  • These propane gas heaters are simple to install and maintain in any small or limited space location.


Our range of instantaneous tankless water heaters, are available in either natural gas or LPG Gas. LPG (Liquefied Petroleum Gas) is a gas that exists in a liquefied form, and is a very popular fuel for heating homes, and also in commercial applications such as caravan parks, leisure parks and any other categories where mains gas supply is not available.

The most common LPG (Liquefied Petroleum Gas) gas used for water heaters is propane, as this gas is ideal for outdoor use, as it is not affected by cold weather conditions that we can have in the U.K and Northern Ireland.

This gas has a classification of “G31 Propane”, and can either be stored in larger tanks or mobile cylinders.

Should you wish to run your flow water heaters on (LPG) propane gas, we would recommend a bulk gas tank, however you can run these units of gas cylinders for example – a 47kg propane cylinder maximum continuous off take rate is per hour 32.94 KW, for heaters rated above this input, your LPG hot water heating system will require more than one and thus automatic changeovers valves sets are used or a bulk lpg tank.

For the above reasons, our LPG gas water heaters are very popular in camping and caravan sites, for shower blocks or restaurants and with sports / leisure facilities, such as football and rugby clubs, again for showering facilities, as these water heaters can be used in multiples or in a cascade configuration to give its official name.


For a gas water heater to condense, the water coming into the contact with the heat exchanger, must be under the dew point of 54°C or lower for propane gas– the maximum incoming cold water temperature, even in the height of summer is 20 Degrees C for the UK, meaning you’re going to have the water heater operating in the condensing mode all year round!

Thus, this gas fired condensing water heater process will deliver up to 105% net thermal efficiency, resulting in significant energy savings when compared to conventional non-condensing gas fired water heaters.

Ultimately, condensing propane water heaters just make perfect sense. They are slightly more expensive than non-condensing versions, but that price is warranted with lower running costs and lower impact on the environment.

We do however, produce one unit, which is a non-condensing water heater for the cost conscious, our “SF Low NOx Evolution” model, which is available with a power output of 24 kW. This has been a very popular model for the domestic / caravan water heater market, although most consumers can now see the benefit of the condensing hot water heaters, with the market moving towards this type.

Our range of instantaneous tankless water heaters, are available in either natural gas or LPG Gas. LPG (Liquefied Petroleum Gas) is a gas that exists in a liquefied form, and is a very popular fuel for heating homes, and also in commercial applications such as caravan parks, leisure parks and any other categories where mains gas is not available. We have many customers who just want to supply just one bathroom or multiple bathrooms – which we can achieve.

The most common LPG (Liquefied Petroleum Gas) gas used for water heaters is propane, as this gas is ideal for outdoor use, as it is not affected by cold weather conditions that we can have in the U.K and Northern Ireland.

This gas has a classification of “G31 Propane”, and can either be stored in larger tanks or mobile cylinders.

Should you wish to run your flow water heaters on (LPG) propane gas, we would recommend a bulk gas tank, however you can run these units of gas cylinders for example – a 47kg propane cylinder maximum continuous off take rate is per hour 32.94 KW, for heaters rated above this input, your LPG hot water heating system will require more than one and thus automatic changeovers valves sets are used.

For the above reasons, our LPG gas water heaters are very popular in camping and caravan sites, for shower blocks or restaurants and with sports / leisure facilities, such as football and rugby clubs, again for showering facilities, as these water heaters can be used in multiples or in a cascade configuration to give its official name.


There are three important factors to consider when selecting the correct water heater for your requirements.

The standard water temperature for bathing or washing is 40 Degrees C

In essence, it’s just a simple matter of the law of physics – the larger / more powerful the lpg water heater, the greater the flow rate of hot water. This is especially true, when in the winter months, as the mains cold water entering temperatures drops, and this is an important factor to consider in UK.

Thus, the amount of warm water the lpg gas water heater will produce and directly related with the temperature rise that the water heater is required to achieve (more on this in point 2). You basically need to cover the flow rates of your hot water appliances, with your usage patterns.

Flow rates

Kitchen sink taps – 4 to 6 litres per minute

Sink taps – 4 litres per minute – standard type

Basin / cloakroom “spray taps” – 2 litres per minute –

A standard shower head has a hot water demand of 7 or 8 litres a minute,

Bath mixer taps – modern bath taps have an approximate demand rate of 12 Litres per minute

So be adding all of your potential hot water outlets, then applying a diversity factor (a factor that not all of the hot water outlets will be used at the same time) you can calculate your hot water demand

Water Heating – Temperature rise

The temperature rise that the gas multipoint water heater has to achieve. This is also known as T ° variation or delta T which when abbreviated looks like this “ΔT”. Quite simply the amount of hot water produced by any hot water heater, is directly affected by the temperature rise of the hot water required. An example of this is –

If you set the hot water temperature to 35 ° C and the cold water entering the multipoint gas water heater is 15 ° C, then you have a variation of temperature or delta T of 20 ° C (35 ° Degrees C minus 15 ° Degrees C). Alternatively, if the appliance was set to a desired hot water temperature of 40 ° C, then the temperature rise or delta T would be 25 ° C (40 °- 15°) and thus the flow rate achievable changes

Mains cold water temperature for the UK

The incoming mains cold water temperature for the UK, for various regions is as follows –

We have two sources of information here –

mains cold water temperature for the UK

Mains cold water inlet temperatures for the UK by region Source – Energy Saving Trust – 2008


Or the blue line on the following chart

mains cold water temperature UK;

Please see the Blue line for the average mains cold water temperature for the UK over a 12 month period


The above chart shows the coldest water temperature in January at around 5 Degrees C – Source TUV

Please use whatever data your comfortable with

LPG Fired Water Heater Range

We do both a domestic LPG water heater and a commercial heater range, both of which have great temperature control, energy efficiency and capacity.

Unlike a lot of our competitors, we are more than proud to publish our performance data at many different temperature increases, as there may be applications – such as commercial kitchens or other applications which require the water to be produced at higher temperatures, such as industrial hot water systems.

The first and smallest unit is our SF14 model which is a 24kW non condensing low NOx model – this unit benefits from-

  • 16mm diameter heat exchanger water ways – the largest we know of on the market (except our condensing lpg units – which are an incredible 28mm in diameter) this size ensures very low pressure drops, guarantees lower risk of clogging, greater thermal efficiency, and greater ease of cleaning. – especially important in areas with hard water

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    SF14 – LGP tankless water heaters from Flexiheat UK – Internal picture

  • Wet chamber copper heat exchanger that prevents thermal inertia
  • Reduction of initial water over temperature with low flow rates
  • Very low NOx emissions, maximum 50 mg / kWh – better for the environment.

DHW performance for the SF14 unit is –

We class the Red figure – as worst case winter performance , and the Yellow figure as the hight of summer performance


SF14 low nox lpg water heater hot water performance by Flexiheat UK

SF14 Low NOx water heater hot water performance by Flexiheat UK

This model is a perfect solution to the hot water requirements for domestic properties and also some light commercial applications.


The next range is our condensing lpg instantaneous domestic hot water heaters , which are the most efficient that you can find on the market- there are 3 models in this range, and two different options.All unit will require a condensate drain

SFC range – for direct feed to the water outlets (the most common application)

SFK (for dhw recirculation systems) with an in inbuilt pump, the larger 50 model is only available with the inbuilt pump, its up to you whether you use it or not

The performace is the same for the direct feed and pumped versions

28kW Model performance data


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SFC and SFK28 LPG Domestic hot water performance by Flexiheat UK


34kW Model performance data


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SFC and SFK34 LPG Domestic hot water performance by Flexiheat UK

50kW Model performance data


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SKF50 LPG Domestic hot water performance Flexiheat UK

Flue Options

We do various flue options, the most common is a co-axial , which takes the combustion air from outside , and flue gas from the device to the outside – making these units room sealed

The most common flue kit is our horizontal co-axial flue kit

Horizontal Flue Kit - Co-axial room sealed by Flexiheat UK;checkout;mail;ratings;vat;sign;vat;users;checkout

Horizontal Flue Kit – Co-axial room sealed by Flexiheat UK

Or the vertical flue kit

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Vertical Co-axial flue kit from Flexiheat UK


Using a split flue system, we can achieve flue routes of up to 60 metres

LPG tankless water heater UK

We carry stock, and use a small pallet service to deliver anywhere in UK and Northern Ireland.

For more information, advice or to find /learn more on our brand of products,which are lpg gas water heaters / lpg gas water heaters with indoor or outdoor versions at great prices and quality, or for delivery times, to place an order, get prices then email us at or give our sales team a call on 01202 822221.A full VAT invoice is supplied for all items supplied.


How to size a commercial water heater

How to size a commercial water heater

How to size a commercial water heater by Flexiheat UK; industrial water heating sizing;

How to size a commercial water heater by Flexiheat UK

A commercial water heater is required for supplying warm or hot potable water for showers, bathrooms, kitchens, restaurant sinks, washing machines etc and other purposes in a commercial or industrial building, such as schools, hotels, gyms or hospitals. A commercial water heater uses electrical elements or a burner to heat cold water up to the desired hot water temperature which is used when a demand is placed on water heater. Water heaters may use a tank to store the heated water for when it is required. Sizing a commercial water heater is relatively easy process and not a ” dark art ” as some people may think.

They are also used in many industrial water heating applications, when hot water is required for a production process, such as commercial laundries or other uses, as part of manufacturing a product or service.

If you size or select a commercial water heater with more than the capacity required, you’ll end up with higher capital cost and also higher fuel bills than required, on the other hand If you undersize a commercial water heater, then you run the risk of running out of potable hot water, and upsetting your customers in the case of a hotel for example or your production process failing in the event of a hot water process application. Thus, we have written this “How to size a commercial water heater” guide to assist in the correct selection for your water heater requirements.

Commercial water heater definition

A water heater can be defined as a closed tank used to supply potable hot water, which is either heated by electricity, gas (Natural gas or LPG), or any other source, such as solar. The water heater is intended to be supplied with potable water either from a potable water supply, such as directly from the water mains system (these are referred to as unvented hot water system) or via feed tanks when used in an open vent hot water system.

The three vital elements to bear in mind when sizing a water heater for commercial or industrial applications


Water storage tank capacity: The tank or vessel capacity for storing the hot water required. The tank allows a large volume of water to be drawn at flow rates that can exceed the recovery capacity of the water heater- which is useful for peak hot water demands.

The recovery rate: The amount of water in litres per hour, raised at a given water temperature rise and kW input. Also often quoted is the one hour draw capacity of the water heater, which is the maximum hot water production for one hour, normally required at the peak period of the day when the heaviest requirement of hot water will occur.

The power or energy input of the water heater – The amount energy required, normally measured in Kilowatts consumed by the water heater, which is provided by your preferred fuel, either electric, gas or oil. One kW of energy is 3,412 Btu’s, if you use the old imperial system.

These three factors are used together to select the correct water heater size and power rating.

The best method for selecting a commercial or industrial water heater is on the basis of hot water usage. The selection is a combination of these factors of tank size, recovery rate and heat input.

What size water heater do I need calculation for commercial water heating applications

Following is the European standard for hot water demands to DIN 4708, that is commonly used when sizing your commercial water heater or industrial water heater- whichever you may classify your water heater as.


Commercial Building TypeDemand factorBath tubShowerBidetPrivate wash basinPublic wash basinKitchen sinkSlop sinkBar sink
Hotel & Hostels / B&B’s0.550501010158050100
Sport centre / Gym’s12205158040100
School (Day type not boarding)0.81805208040
Commercial Offices15104040

Calculation example for a commercial water heater hot water demand

A Hotel with 100 rooms = Litres of hot water / Hour at 60 °C

  • 100 Bath tub / showers = 5,000
  • 25 Bidets = 250
  • 100 Private wash basins = 1,000
  • 20 Public wash basins = 375
  • 5 Bar sinks = 500
  • 8 Kitchen sinks = 640
  • 5 Slop sinks = 250

This gives us a total hot water demand of 8,015  x the demand factor for a hotel water heating system sizing of 0.5 = 4,007.5 litres per hour continuous at 60 °C

With a commercial hot water requirement / application like this, due to the volume of water required, the only practical solution is a commercial storage water heater, we do a full range of commercial gas water heaters, that we can match to various storage volumes of up to 5,000 litres in a single storage tank ( more when used in series)  and a power input of 300kW. They are also condensing too, thus you’ll have the maximum efficiency for your hot water commercial system.

We also supply commercial water heaters powered by an oil burner, and this range of oil fired water heaters is fuelled by gas oil which is the preferred oil used in commercial and industrial water heating applications.

As well as electric powered which we speak in more depth below in this webpage

Hot water demands for apartment blocks with a communal / centralized hot water system

A standard apartment or flat according to DIN 4708 is defined as consisting of 4 rooms, with 3 /4 persons living there, a 150-litre bath (with a fill time of ten minutes) with one wash basin and one kitchen sink.

It also specifies, within the standard, that the hot water storage capacity and the performance of the heat exchanger in terms of efficiency are both significant factors in determining the number of apartments a water heater or heaters can serve. A general guide is as follows  –

Number of apartmentscontinuous  requirement (litres per hour)
Domestic Hot Water Temperature60 °C45 °C


Commercial electric water heater sizing

You size a commercial electric water heater, on the exact same principles as a gas or oil powered version, just the fact that you require electricity as the fuel source or power for the water use the above data to establish your hot water requirement, then look at our webpage commercial electric water heaters, for the available sizes and power outputs than we can supply. Just make sure you have the Amps available to power the unit.

Commercial tankless water heater sizing

Sizing a commercial tankless water heater is a different case, as a commercial tankless water heater heats up water on demand rather than storing warm water in a storage tank for later use. This means they are generally more efficient as they only ever heat as much water as you need and are smaller in size than storage water heaters.

But they have a down side as heating water on demand requires using a larger burner in the case of a gas or oil-fired commercial water heater or electrical heating elements than a commercial storage water heater would use, which means that the energy demand while heating the water can be very high. So, you have to ensure you have the power available to satisfy this requirement.

The most common commercial tankless water heater is gas powered, as gas ( either natural gas or LPG gas ) is great at producing a lot of energy via a relatively small supply pipe.

You size commercial tankless water heaters via the number of hot water outlets they have to satisfy, and to what water temperature, we go more into this on this dedicated webpage – gas multipoint water heaters, that are used in commercial tankless hot water systems.


Industrial water heater sizing / calculation

Often industrial water heaters, are sized in a slightly different method, as normally, there are different water temperature rises, specifically required for the process in question
For industrial water heating processes, there are normally 3 elements to sizing your water heater.

These are –

1. The volume of hot water that you require – How many litres of hot / warm water do you require?
2. The temperature rise that you want that water to go through e.g., from the incoming water temperature of 10 degrees C to 70 degrees C etc
3. Lastly your time requirements – how quickly do you want that water to heat up in, or how many litres you require of water per hour your process requires.

When you have established these factors, then you can use the following calculation to establish the kw rating required for you water heater
To heat a specific volume of water by a given temperature rise in one hour.

Volume of water in litres x 4 x the temperature rise in degrees centigrade divided by 3412

(just for note – 4 being a factor and 3412 being a given constant)

Thus, for a 1,000 litre water heater, the calculation would be as follows –

1000 litres of water, to be heated from say 10°C to 70°C, giving a temperature rise of 60 °C would result in-

1,000 x 4 x 60 / 3412 = 70.339 kW per hour

This means that the 1000 litres of water would be heated in one hour by 70.33 kW of applied heat, for the temperature rise of 60°C, whether its by gas, oil or electric

We can use this result to conclude other factors – e.g., to heat the same water volume of 1,000 litres in half the time (i.e., 30 minutes) we would need twice the heating power i.e. 140.66 kW, as 70.339 x 2 = 140.66 kW.

Should the process require a 2-hour period recovery period for the industrial water heater, then we can lower the power input to 36.16 kW
When sizing an industrial water heater and for a commercial water heater, these are the actual power input figures into the water heater, so you need to ensure that the heater has a nett input of this figure, but its also prudent to add a small percentage for standing heat losses, if you are using a storage water heater.

Alternatively, if you have a specific water temperature rise, and you know the kW input rating of the unit, then you can calculate the water flow rate produced, then use the flowing formula –

m (kg/s) = P (kW) / the specific heat of water (Kj / Kg ºC) X ΔT of the water in Degrees C

Whereby –
m = mass flow rate (kg/s) this is litres per second as one litre of water weighs one kilogram
P= Power in kW
Specific heat of water = 4.187 Kj/Kg ºC
ΔT = temperature increase in C

An example
A water heater, with thermal power input of 70 kW, with a temperature rise of 60 degrees C then it would be –
m = (70kW) / ((4.187 kJ/kg ºC) (60ºC))
thus – 70 / 4.187 x 60
70/251.22 = 0.2786 kg/s or 0.2786 Litres a second – times this by 60 seconds to get per minute then by 60 minutes to get the volume per hour – thus 1,003 Litres per hour for a 60 Degree C water temperature rise.

Hopefully this sizing / calculation guide for commercial and industrial water heating applications has provided the information and formulas to help you size the correct water heater for your application. Should you require any more information on our water heaters, please don’t hesitate to contact us at Flexiheat UK

Combi boiler for a large house

Combi boiler for a large house

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Combi boiler for a large house from Flexiheat UK


Looking for a combi boiler for a large house? Here we go through the issues that you need to consider when selecting the best combi boiler for a large house to suit your requirements. Selecting the correct combi boiler size for any home, is critical, especially when your residence is a large house, with multiple radiators, or an underfloor heating system and multiple bathrooms, it then becomes vitally important if you require a high efficiency and economical boiler with exceptional hot water flow rates then we have the perfect combi boiler for your large house / home/ property.

What is a Combi boiler, and what do they do ?

Firstly, we need to establish, what a combi boiler is? Well the boilers official name is a combination boiler – but over the years this has been shortened just to “combi boiler “. These boilers are now the most popular type of boiler for homes, flats etc in the residential market for the UK. A combi boiler not only supplies the heat for the central heating of the home, but also heats the domestic hot water instantaneously as a hot water tap is opened.

Another benefit of a combi boiler is that the hot water is fed from the mains water supply, eliminating the need for a feed and expansion tanks, and thus the water pressure is often higher, resulting in better hot water performance.

These factors make a combination boiler one of the highest efficiency boilers on the market, with an attractive low cost purchasing price, along with the lower installation costs and continual lower running costs than the older type system boilers that were extensively used in previous times in larger homes or properties.

There are two main elements to a combi boiler, which need to be considered when selecting the correct boiler –

  1. The heating side of the boiler– You need to establish how much of a heating load or requirement your large property will have. This is to ensure that the boiler has sufficient capacity to heat your large home
  2. The Domestic Hot Water performance– This is the hot water that you use to bath, wash or doing the dishes / kitchen use – when preparing meals etc

We will look at both of  these issues and give you the guidance to ensure that you have the best solution for your combination boiler for a larger house / property.

Combi boiler sizing for large homes / properties

The first part is the easier bit as they say. It doesn’t matter what heat emitters you are using to heat your home, whether it be a radiator system or an underfloor heating system or even a combination of both. The principle of heat loss sizing for your property doesn’t change.

Basically, the fabric of your home loses heat, depending on how well insulated the building materials used, such as the brickwork, the floor and the roof. This is known as the “U “value of the materials in question.

This” U “value is official expressed as the rate in Watts [W]) at which heat transfers through 1 square metre [m²] of the surface of a buildings material when there is a temperature difference of 1ºC between the internal and external environments.

So, if you have a property built from the late 1990’s onwards then you are safe to use this ready reckoner chart. This ready reckoner table is based on a brick and block cavity wall with mineral wool insulation having a total wall thickness of 312 mm has a “U” value of 0.3 W/mtr. The building regulation from the late 1990’s specify that this “U” value must be achieved, to pass the building regulations.

You need to ensure that you have the total floor area of your home, including the ground level, 1st floor, 2nd floor etc. It is the home’s / properties total floor area you need to calculate.

Power Output of BoilerHeating area with Height of 2.7 Mtrs & U Value of 0.3
4.5 kW~ 55 Mtrs/2
7.5 kW~ 85 Mtrs/2
9 kW~ 110 Mtrs/2
13.5 kW~ 165 Mtrs/2
15 kW~ 180 Mtrs/2
22.5 kW~ 278 Mtrs/2
24 kW~ 300 Mtrs/2

For example – If your large home has a total floor area of 600 M/2, then you’re going to need a 48 kW Combi boiler (2 x 300 m2 = 2 x 24 kW – thus a 48kW output combi boiler)

If your total floor area is 440 M/2, then you’re going to need a 48 kW Combi boiler (1 x 300 m2 =  24 kW  and 1 x 165 M2 = 13.5 Kw –always go up on the chart – you can turn a combi boilers output down , if you have it there , but you can never turn it up , if it doesn’t have the capacity – thus 24kw + 13.5 Kw = 37.5 kW  total boiler output

Our combi boilers for large homes are modulating boilers, which means they will automatically ramp up and down their heat output to suit the central heating requirements. They are very clever boilers these days !

Domestic Hot Water Performance of the Combi Boiler for a larger property

Ok, now for the second part of a combi boiler for a large house– the domestic hot water performance / sizing – and this these days is the most important factor when selecting the best boiler to suit your requirements.

Traditional combi boilers use a plate heat exchanger to heat the domestic hot water up to temperature, from the “heating water side of the boiler “. They have benefits in that they only heat the hot water when there is a demand.

But they also have some minus points, which really come into factor when trying to fulfill the hot water demands when used in larger homes, with multiple bathrooms, or many hot water taps.

Because a combination boiler draws all of its water supply directly from the mains water supply, these boilers struggle to meet high demands for the hot water. An example of this, is when multiple hot water taps are turned on in various bathrooms, the kitchen or other rooms within the house, you will often see a dramatic reduction in the water pressure.

This is caused by the combination boiler not having the benefit of a storage hot water tank, which would meet these levels of demand.

We’ll we at Flexiheat UK have solved that problem, we basically have a “hybrid combi boiler” or a “combi boiler with an element of storage”, which makes them especially suitable for larger homes, that usually have larger hot water demands via multiple bathroom or showers.

Another benefit of having an element of hot water storage is that the larger the property, the longer the hot water pipe runs tend to be, so depending on the property layout you can install a secondary domestic hot water return, which eliminates the delay for the hot water to get to the taps around the home, this also eliminates what is referred to as “hot water dead legs”.

So this brings us to our range, and why our boilers are regarded as the best combi boiler for a large house

We do three models –

our 45 model – which is a combi boiler that modulates its output all the way from 11 to 45 kW for the heating side of the boiler and will produce 44.2 kW of heating power for the domestic hot water demand

the 55 model – which is a combi boiler that modulates its output all the way from 12 to 55 kW for the heating side of the boiler and will produce 54 kW of heating power for the domestic hot water demand

or the largest model – our 65 unit – which is a combi boiler that modulates its output all the way from 13.5 to 65 kW for the heating side of the boiler and will produce 64 kW of heating power for the domestic hot water demand

Each of these boilers are available with a hot water tank in either 60 , 90 or 120 litres of storage , which can handle a domestic water pressure of up to 6 bar ( any more than 3 bar ,

and a shower can start to get painful with the water pressure , and your taps turn into powerful water jets , often with the water coming out at such a force , that it goes everywhere.

But here is the element which makes the combi boilers the best choice for a large house – the Domestic Hot water performance – it literally is phenomenal, remarkable or exceptional – however you want to call it.

To explain how good it is – here are some stats –


According to BS6700 a standard bath (1700mm x 700mm) full capacity is around 180 litres to overflow level, but most people fill their bath tubs to around half way to allow for the displacement of water when they get into the bath. So, the actual volume of water used is 100 litres.

The normal bath water temperature is around 40 Degrees C

When you have stored water, this is kept at 60 Degrees C to prevent legionella, which is then blended down with cold water to achieve the 40 Degrees C, at a ratio of 60% hot water and 40% cold water, or 60 litres of hot water and 40 litres of cold water to make up the 100 litres.

Thus, a bath cycle requires 60 litres of hot water, stored at 60 Degrees C

The 60 litre tank, would recover it’s hot water in 6.30 minutes, (which means you can start filling a bath 6 minutes 30 seconds after filling the previous one )  the 90 litre in 6.30 minutes ( one and a half baths ) and the 120 litre unit in 6.30 minutes ( two baths simultaneously )  , which is very impressive domestic hot water performance indeed, as these combi boilers have a hot water priority system.


The figures are even more impressive for showers –

According to all the data, a standard 5-minute shower approximately 45 litres of water at 40 degrees C, which uses 27 litres of hot water stored at 60 degrees C – with a standard shower head. From this data – our 60-litre hot water storage tank will do 2 shower – simultaneously – the 6 and half minutes later you could go again

Our 90 Litre – 3 showers, again simultaneously – 6 and a half minutes, you can go again

Our 120 Litre – 4 showers with a little spare, again simultaneously – 6 and a half minutes, you can go again

In reality , we would say , that the persons wouldn’t have even come out of the shower room or bathroom, as they need time to dry off , shave , clean their teeth , do their hair etc, before the hot water tank has recovered all of the hot water, in this way you could almost say that you have infinite hot water and all at a great water pressures – no limp or poor showers here !


Water Pressure

As a combination boiler draws all of its water supply directly form the mains water supply, they can often struggle to meet high water demands, especially in large properties like a 4 or 5 bedroom house .We have all seen what happens when a person turns on a hot water tap when someone is having a shower, and the dramatic drop in water pressure , normal followed by a shout “ turn that tap off “ I’m having a shower , this is due to the fact that a true combination boiler has no hot water storage tank like our boilers, which overcomes this problem, and allows multiple hot water taps or outlets to be used simultaneously, at good water pressures.

Full technical details for our combi boiler with storage for larger properties

These combination boilers for larger properties – can be fired with either natural gas or LPG / Propane Gas

TECHNICAL SPECIFICATIONSModelFH-S DHW      45SFH-S DHW      45MFH-S DHW      45LFH-S DHW      55SFH-S DHW      55MFH-S DHW      55LFH-S DHW      65SFH-S DHW      65MFH-S DHW      65L
Thermal Capacity – Heating
Maximum Heating CapacitykW454545555555656565
Minimum Heating CapacitykW11111112121213.513.513.5
Maximum Heat Discharge for Heating (80°C / 60°C)kW42.442.442.453.453.453.4646464
Minimum Heat Output for Heating (80°C / 60°C)kW7.
Maximum Heat Discharge for Heating (50°C / 30°C)kW45.845.845.857.
Minimum Heat Load (50°C / 30°C)kW8.
Maximum Domestic Water CapacitykW44.244.444.854.154.554.764.264.664.8
Thermal Efficiency
Efficiency @ Pmax. (80°C / 60°C)%97.497.397.797.597.397.797.397.297.2
Efficiency @ Pmin. (80°C / 60°C)%98.598.698.798.899.198.20%98.698.398.6
Efficiency @ Pmax. (50°C / 30°C)%105.2105.3105.4105.3105.2105.1105.6105.3105.6
Efficiency @ Pmin. (50°C / 30°C)%107.4107.6107.2107.2107.2107.2107.1107.3107.4
Efficiency @ 30% (30°C)%108.7109108.2108.1108.7108.5108.6108.4108.7
Domestic Water Circuit
Domestic Water Temperature Adjustment Range°C10 -6510 -6510 -6510 -6510 -6510 -6510 -6510 -6510 -65
Domestic Water Storage Tank VolumeL609012060901206090120
Domestic Water Flow Rate in ContinuousL / dT12.118.424.
Use (∆T=25°C. 20 °C /45 °C)
Heating & DHW Pressures
Maximum Operating Temperature- Heating°C858585858585858585
Maximum Operating Pressure- HeatingBar444444444
Minimum Operating Pressure- HeatingBar0.
Maximum DHW PressureBar666666666
Gas Properties
Gas TypeG20-G31G20-G31G20-G31G20-G31G20-G31G20-G31G20-G31G20-G31G20-G31
Gas Inlet Pressure (G20) Natural Gasmbar202020202020202020
Gas Inlet Pressure (G31) LPG /Propane Gasmbar373737373737373737
Combustion Values
Maximum Flue Gas Outlet Temperature (50°C / 30°C)°C424242444444454545
Maximum Flue Gas Outlet Temperature (80°C / 60°C)°C656565656565656565
NOx Emission  Class (EN 15502-1+A1)555555555
Electrical Values
Voltage & FrequencyV / Hz230/50230/50230/50230/50230/50230/50230/50230/50230/50
Energy ConsumptionW190190190210210210300300300
Hydraulic Circuit Properties
Gas Connectioninch1/2”1/2”1/2”1/2”1/2”1/2”1/2”1/2”1/2”
Heating Circuit Flow & Return Connectionsinch3/4″3/4″3/4″3/4″3/4″3/4″3/4″3/4″3/4″
Domestic Water Circuit Flow & Return Connectionsinch1/2″1/2″1/2″1/2″1/2″1/2″1/2″1/2″1/2″
General Features
Net (Dry) Weightkg95110125100115130105120135
Flue Diameter (Ø)mm80/12580/12580/12580/12580/12580/12580/12580/12580/125
** G20 Natural Gas.    G31 LPG
Control options for the boilers

Everyone now wants to be able to control their boiler, when they are out and about, be it travelling or at work or even on a plane – having the facility to turn your boiler on and have the house warm for when you return to it has now become almost standard. Well the good news is that combi boiler can do this – they have a control panel is also what is called “OpenTherm Plus “compatible, which means you can control these combi boilers, via the use of an OpenTherm controller, such as a “nest” type or similar.

This means you can make your life simpler and control these combination boilers from either your mobile phone (android or apple) your PC or tablet, from anywhere in the world, as long as you have an internet connection.

The control panel also has numerous inbuilt features such as –

  •  Frost Protection – Full protection against freezing of the heating and domestic hot water in low ambient temperatures
  • Pump Protection system – Anti-blockage System -The circulation pump is activated automatically once every 24 hours and prevent any blockage
  • Ability to operate according to different heat demands with the variable flow pump control
  • Low fuel consumption and fixed combustion efficiency thanks to the PWM driver, high modulating fan and high modulating gas valve
  • Ability to operate according to different heating system configurations
What are you waiting for ! Call us, for the best combination boiler for large properties

So should you be looking for a combi boiler for a large 4 bed house or for a 5 bedroom house , with 2 , 3 or even 4 bathrooms , you can now see why our combi boiler is the best option , as the element of some hot water storage , which is as small as possible , and thus saving on wasted energy , but large enough to cope with the hot water requirements of a large home or property, then please don’t hesitate to contact us at Flexiheat UK, using the contact us function at the top of this web page, or alternatively give us a call on 01202 822221.As we believe we have the best combi boiler for 4 bedroom house and the best combi boiler for 5 bedroom house for sale on the UK and Irish market.


Fan Coil Heaters

Fan Coil Heaters

Fan coil heaters; hot water heating fan coil; fan coil heater units; fan assisted air heaters;

Fan coil heaters from Flexiheat UK

Fan coil heaters are devices or units that consist of a heat exchanger or coil, which has a fan behind it, to provide a steady stream of fan assisted warm or hot air, which is then used to heat the area quickly and efficiently. They require warm or hot water to feed the coil or heat exchanger, which then transfers it’s heat into the surrounding air,as the fan that is situated behind the coil or heat exchanger pushes the warm air out.Thus, sometimes these heaters are sometimes referred to as fan assisted air heaters.

Typical applications for fan coil heating systems include –

  • Factory Heating
  • Warehouse Heating
  • Garden Centre Heating
  • Sport Centre and Stadium Heating
  • Workshop Heating
  • Shopping Centre Heating
  • Church and other places of worship Heating
  • And many other retail outlets, such as car showrooms,
  • Poultry Shed Heating – we do a special unit specially designed for this duty
  • Pig Shed Heating – again, we do a special unit for this application
  • Barns and Storage areas Heating

These are just a few on the many applications these heaters are suitable for. They are very widely used in warm air heating applications that use biomass boilers, that are producing warm water, to transfer that energy produced into warm or hot air.

Fan coil heating

Using fan coils for heating has been popular and been around for many years – it is a proven method for heating commercial and industrial buildings. They can be used in either re-circulated air from withing the building, or can be used to heat in coming fresh air into the building or even a combination of both, via a mixing chamber.

Advantages of these fan coil heating units are –

1.Capability to heat large buildings or areas

2.High efficiency

3.A heating system with low inertia – heating the building in a very short period from initial start-up of the heating system.

4.Even distribution of the heated air – vital to ensuring an effective warm air heating system, using these fan assisted space heaters

5.Relatively low purchasing price – ensuring a competitive solution to the warm air heating of buildings.

Hydronic fan coil heaters

Hydronics is the use of a liquid heat-transfer medium in a heating system. Thus, these heaters are sometimes referred to as hydronic fan coil heaters, as the heaters use pumped hot water, that flows through the heater coils. These coils have a fan fitted behind them, which blows the air across the coil, and takes the heat from the coil – thus heating the area in which the hydronic fan coil heaters are located.

Water to air space heater construction

We do two ranges of fan coil unit heaters – you can have a steel cased heater or an EPP-cased heater. EPP stands for Expanded Polypropylene, which is a plastic that has some unique properties such as multiple impact resistance, exceptionally high strength to weight ratio, high water and chemical resistance and the last but most important point, is that EPP is 100% recyclable.These features and benefits would be difficult to find in any other material.

Both ranges can be either wall mounted or ceiling mounted, ensuring that your heaters are off the floor, and not using up any valuable floor space as well as they are also out of the way of any potential damage from knocks or bangs.

The steel cased heated are suitable for hot water temperatures of up to 150 Degrees C or lower and with the warm water operating pressure of up to 16 Bar. The range of heat output is from 6.5 kW to 344 kW depending on the temperature of the hot water used, and how many rows of heat exchangers or coils that they are fitted with.

We go into full detail on this range of steel cased units , on this dedicated web page –

This page will concentrate on the EPP cased fan coil heater heater range –

Heating capacity from 0.7 kW to 121 kW, which is dependant on the flow and return temperature of the wet heating system feeding the heaters. The output performance is also affected by the entering air temperature to the fan coil heaters, as the colder the air entering is, the more ability that air has to absorb the heat from the heat exchanger. The air flow is from 1, 000 to 5,800 M3/hr, again depending on what model.These units are detailed on the brochure below –

Download the Fan Coil Heaters brochure from Flexiheat UK

They can also be fitted with mixing chambers, which when connected to our fan heaters effectively creating a heating and ventilating system.

We do a full range of controls, from a simple three step manual fan speed regulation, with a room thermostat all the way up to a full BMS compatible controller, that features automatic three-step air flow regulation, with a weekly programmer, thermostat and the possibility to connect up to 31 units via single controller. This controller can either stand alone or be connected to a full BMS (Building Management System).

We also offer all the standard accessories such as two or three port control or zone valves – These should be fitted to the pipework just prior to the heater. Thus, when the heater is not required to operate, the warm water flow to the heater is stopped, preventing the heated water flowing through the heating coil, which would generate heat, even though the fans of the heaters would be off. This results in wasted heat energy, and in a higher fuel usage than required.

We also offer flexible stainless-steel pipework kits, that make connecting the fan coil heater to the fixed pipework very quick and easy, reducing the install time.

Heating Coil

The heating coil is constructed from copper tubes with aluminium fins attached to them. The water coil or heat exchanger can be supplied by warm water or a glycol solution up to 60% in strength. The working parameters of these fan assisted water heaters is 16 Bar, and a maximum temperature of the warm water is 120 Degrees C. The units come with heating coils that have 1,2 or 3 rows depending on the heat output of the model.The flow and return water connections of the heating coil are situated at the back of these hydronic fan coil heaters.

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Water to air coil or heat exchanger used in these fan coil unit heaters – They can have 1,2 or 3 rows of coils

Air Delivery Louvres

The air delivery louvres are constructed of polypropylene, and are fully adjustable, ensuring the heat generated from the fan coil heating system can be adjusted in its direction, ensuring that the heated air flow gets to the required areas and does it job.

Fans – Axial Blowing – Fan assisted coil heaters

These hot water fan coil heaters have axial fans fitted to them, to blow the heat generated from the heating coil into the area to be heated. These fans are protected with a strong steel wire grid cover, whilst the fans blades used are made from lightweight, but strong steel. All of these fan heaters are powered by 240 Volt single phase fans. The fans fitted are IP/ Insulation class 54 accredited/ rated ensuring high safety levels.

Mounting Brackets – Rotary

These brackets allow the fan coil heaters to either be wall mounted or ceiling mounted to suit your site requirements. You can choose to mount these heaters with an angle of 45,60 or 90 degrees, and these hydronic heating fan coil units can also be rotated through 170 degrees in the horizontal plane.

hot water heating fan coil; fan coil heater units; fan assisted air heaters; fan coil heaters;

Mounting options for Fan Coil Heating Units / System

Hot water fan coil heater

The Flexiheat range of fan coil heaters are the perfect commercial or industrial air heating solution.These hot water fan coil heaters can be installed to suite the site conditions, be it wall mounted or ceiling mounted.Sometimes these coil heaters are referred to as fan assisted air heaters, hydronic heating fan coil units, hot water heating fan coils. Whatever you call them we have the perfect fan coil heating system for you.for more information either call us on 01202 822221 or email us via the contact form,which is located above.

Electric Combi Boiler UK

Electric Combi Boiler UK

Electric combi boiler UK? – are they available? do they work? Usually when someone says “electric boiler” the majority of people think about the water boilers used to generate instant hot water to a single tap, such as an over or under sink water heater, but these units only produce domestic hot water. Happily, in the UK, electric combi boilers are now a great solution, for not only your hot water requirements, but also your heating requirements.

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Electric combi boiler UK for sale from Flexiheat UK


As the boiler name suggests, they are an option to a gas or oil combi boiler that uses electricity as the energy supply. Despite the fact that technology is nearly as old as the invention of electricity itself, as of late electric combi boilers have seen expanded enthusiasm from people whose properties are not served by the national gas distribution system or who basically want to dispose of their gas supply and move to a greener energy to fuel their central heating and hot water requirements .

Electric combi boiler vs Gas

Knowing that natural gas is a fossil fuel, and therefore can’t be considered a green fuel source. With regards to electricity, if it is generated via renewable energy sources or if you use a wind turbine or solar panels to generate the electricity, you can go totally carbon neutral on your energy requirements. Utilizing electric combi boilers bodes well to individuals who have installed solar panels or wind turbines onto their property. Recent advances in the technology of solar and wind generation fields now make electric combi boilers a real solution for people who want to get off the national gas grid, or don’t want to use oil either.

Beside the fact that electric combi boilers in the UK, have the capacity to be eco-friendly, the other advantage is that an electric combination boiler is often smaller in size than an equivalent boiler fired by gas or oil, and will often fit in locations that a gas or oil boiler won’t , due to the fact that these boilers require a flue pipe or chimney system to operate.

Individuals who have previously experienced on demand electric water heaters, are usually disappointed with the DHW (domestic hot water) flow rate that they have seen. This is solved with our electric combi boilers as they incorporate either a 50 litre, (for the wall mounted version) or 80 litres (for the floor mounted version) pre heated stainless steel hot water cylinder. This hot water cylinder allows these boilers ensure great hot water performance which are similar to their gas boiler equivalents, with the larger floor mounted boiler delivering 13.8 litres per minute of hot water.

Cost of electric combi boilers in the UK

When it comes to the price of electric combi boilers in the UK, they are very similar to their equivalent gas fuelled equivalents, and are generally cheaper than their oil-fired equivalents, with prices generally in the £1,600 to £2,200 depending on the kW output of the boiler in question.  Obviously, they are more expensive than a heat only electric boiler, but when you add the necessary indirect cylinder required to do the domestic hot water requirements, and the controls required to achieve this, then they generally work out cheaper, than going for a split heating and how water system, that uses a heat only boiler and cylinder combination.

Electric combination boiler installation costs

The installation cost of an electric combi boiler in the UK, is often lower than their gas or oil alternative. No flue or chimney system has to be installed with an electric boiler, which cuts down on the labour required and should result in cheaper installation price. They include an inbuilt heating pump and expansion vessel, for both the heating and domestic hot water requirements, as well as safety valves, that ensure they security of your boiler. All that is required is the appropriate electric supply, with the required amps available, and a water supply and your ready to go as they say.

Electric combination boilers are a great choice in elevated buildings such as high-rise structures, as they don’t require a flue pipe system, as no products of combustion are given off with an electric boiler. Can you just imagine not only the logistical and high expenses associated with installing a gas boiler, in a high-rise block of flats, with scaffolding, and working at height legislation to comply with in the UK, just to name a few problems to overcome. These issues are just eliminated when choosing a combination electric boiler, making them a great solution to a complex problem.

Electric combination boiler reviews UK

When reviewing our range of electric combi boilers that we sell in the UK and Ireland, following are a few brief overview of the range we sell –

Our range of electric combi boiler can be powered by a single phase 240 Volt electrical supply from 4.5 kW to 15 kW, which is the largest power output we know of on the UK and Irish market.

We can go all the way up to 21 kW of boiler output, but from 15 kW to 21 kW you require a three phase 400 Volt electrical supply

We do a wall hung or mounted version, that has a 50 litre hot water internal storage vessel housed withing the boiler, thus ensuring good flow rates, and hot water that is hot enough for doing dishes – you require hot water at 50 degrees C to get rid of grease from cooking utensils and dishes. If you only have a shower in your house or flat, then this is the electric combi boiler for you.

We also do a floor mounted version, which has a larger 80 litre internal hot water vessel, again situated withing the boiler casing, this has enough capacity of hot water to run a bath at mains pressure, just as quick as a hot water cylinder would. If you have a bath in the property, again this is the combination electric boiler for you.

All of the boilers, have 6k W of dedicated electric heating power for the hot water production of the boiler.

These electric boilers can be set to a various output, for example the 45/90 model, can be set with an output of either 4.5 kW, 6 kW, 7.5 kW, or 9 kW to suit your heating requirements. These boilers are available in either wall mounted or floor standing versions.

The 10/15 boiler model, can be set to 10 kW, 12.5 kW or 15 kW output, giving you maximum flexibility to suit your needs

Whichever combination electric boiler you go for, all of them are highly efficient, at almost 100% efficiency (actually 99.8% to be precise)

For more full information, please see the following in depth dedicated web page

Should you require any more information or advice, on what we regard as the best range of electric combi boilers UK and Ireland wide, then please don’t hesitate to call us on 01202 822221 or send us an email via our contact form in the top tool bar

Kroll heaters parts prices UK

Kroll heaters,parts and prices UK

If you require parts or prices for Kroll Heaters, then you need to speak to us at Flexiheat UK, as we were the old Kroll UK, until Kroll pulled out of the UK directly over 3 years ago. So, it’s the same basic team, just with a new name for the company, due to legal reasons. We are the authorized distributor for the UK and Ireland for Kroll products. We stock all of the most common spares / parts for the kroll range of heaters, and anything we haven’t got, we just get from the Kroll factory in Germany for you.

Kroll W401L waste oil burner / heater

This is the most popular waste oil heater that Kroll has done – the Kroll W401L, but also used to be called just the W401 when not fan heater was installed on the top. It was also called the W401VL and just W401L heater when it was supplied with the top fan assembly, which blew out the warm air from the waste oil heater.

Unfortunately, Kroll Germany have now stopped producing this heater. We have other options – please see our webpage on our replacement units – manual fired waste or multi oil heaters- for new replacement units. We also still stock and hold spare parts for the Kroll W401L on the shelf in our warehouse based on the south cost of the UK, and supply these to the UK and Ireland

Kroll waste oil heater

We still sell the Kroll ” SZ” range of automatic fired waste oil heater, which as stated previously is for sale in the UK and Ireland. This range has an output range from 25.5 kW all the way up to 180 kW, and needs to have a compressed air supply to feed the waste oil burner. This automatic waste oil burner can be wired into a programmer, so that it operates on a timer. There is no need to manually fire these heaters up, as long as there’s compressed air available with the automatic range, the Kroll waste oil heater does it all

Kroll waste oil heater for sale

We still sell the Kroll ” SZ” range of automatic fired waste oil heater, which as stated previously is for sale in the UK and Ireland. This range has an output range from 25.5 kW all the way up to 180 kW, and needs to have a compressed air supply to feed the waste oil burner. This automatic waste oil burner can be wired into a programmer, so that it operates on a timer. There is no need to manually fire these heaters up, as long as there’s compressed air available with the automatic range, the Kroll waste oil heater does it all.

The Kroll “SZ” waste oil heater package is actually made up from two components, the KG/UB waste oil burner matched to a Kroll “S” range heater. When coupled together they are designated the Kroll “SZ” waste oil heater package. The “S” range heaters are a well-made warm air cabinet heater, that from the 25kW to the 110kW model are constructed with a stainless-steel heat exchanger and combustion chamber which ensures a long and trouble-free product life cycle.

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Kroll waste oil burners from Flexiheat UK

Kroll waste oil burner spares

Again, we still do all the spares for the Kroll waste oil burner models, known as the KG/UB universal oil burner. This Kroll burner will also burn waste oils such as engine, hydraulic and vegetable oils – such as rape seed, sunflower etc. They will also burn recycled vegetable oils that have had the fats removed from them, and fish oils too! – It really is a universal oil burner, having been at the leading edge of multi oil burners now for many years.

So, if you require any Kroll heaters spare parts, for a burner or a heater, or should you require a price on a new kroll waste oil heater, or require anymore assistance or information, please don’t hesitate to contact our sales team on 01202 822221 or click here for our email contact form.

Industrial Unit Heaters

Industrial Unit Heaters –

industrial unit heaters; industrial electric unit heaters;

Industrial unit heaters from Flexiheat UK

Industrial unit heaters come in a wide variety of types for the industrial heating industry, most are versatile in use to cover a wide variety of heating applications, whilst others are designed for specific or niche heating applications.

They are ideally suited to commercial or industrial space heating, as they have an integrated fan, which produces a high volume of air flow which distributes the warm air generated by these industrial unit heaters efficiently and evenly throughout the area of which the units are installed. Depending on the size of the area being heated single or multiple industrial unit heaters may be required, as the effective throw of the warm air has to be considered.

The use of an integrated fan on the unit heaters creates air movement over the heating element surface, quickly and efficiently, this factor ensures that when compared to an equivalent convector type heater, unit heaters are more compact in size, getting more effective warm air heat out of these types of industrial heaters. Our unit heaters are designed to hold up against the typical abuse often seen in commercial and industrial applications or environments being able to withstand dusty and dirty air conditions.

Industrial unit heater – sizing your warm air heating system

Sizing of the most appropriate model and quantity of these industrial unit heaters should always be done on the premises of gaining the optimum efficiency and cost effectiveness both in the initial purchase cost and also the running costs for the warm air heating system.

There are a number of factors, which effective the overall heat load requirement for any commercial or industrial building and the heat that is required to get to your desired working temperatures. The factors that influence this heat load calculation include –

  1. How well insulated the building being heated is.
  2. The amount of air changes per hour this building normally has – i.e. are large roller shutter doors open, and how often they are.
  3. What is your preferred fuel preference – as unit heaters can be fuelled by hot water, electric, steam, natural gas, propane gas or even oil – they choice may be dedicated to you by buildings location and subsequently the available fuel on site.
  4. The efficiency and level of control accuracy of the warm air heating system.
  5. The normal ambient air temperatures you are likely to see in the winter periods – This is an important factor in calculating the size and number of required unit heaters – as you want to ensure that the heating system is adequate to handle the coldest environmental conditions it will endure.
  6. The height of the building will also have an influence on the warm air system, as if the height is large, then the use of destratification fans, to push the warm air back to the ground level where it is required can be used to counter act this natural phenomenon and add to the heating system efficiency.

Should you require any more information on industrial unit heater sizing for your application, then we at Flexiheat UK would be please to help you size your particular warm air heating application. either pop us over an email to or give us a call on 01202 822221 to find out more.

Unit heater types

The heat emitted from these unit heaters can be generated by a variety of fuels, with the predominant factor often being the most readily available and or the most economical fuel source available to the premises.  The most common unit heater types are –

Hot water unit heaters – water fed unit heaters

hot water unit heaters;hydronic hot water hanging unit heater

Hot water unit heaters for LTHW/MTHW or HTHW systems from Flexiheat UK

Often called a “hot water fan heater” or “hot water air heater”- water fed commercial / industrial unit heaters are very commonly used in factories, warehouses, sports halls or workshops. The hot water is normally generated by a boiler which can be fuelled by gas , oil or electric or even a heat pump which heats the water up to the desired temperature before it is circulated via a piped heating system to the unit heaters often at a low pressure ( 3 bar or under )  – thus the term “low pressure hot water” – or LPHW air unit heaters .

They come with the various control options and ancillaries such as thermostats, which can control the operation of the unit heater fan and also can control the water flow to the unit heater by opening or closing a control valve feeding the unit. Commercial or industrial premises with multiple unit heaters can often be controlled by a single controller, which when coupled to external temperature probe can optimize or compensate for the external weather conditions and adjust the warm air heating system accordingly. This results in higher efficiency levels and reduced running cost of the commercial or industrial heating system.

These industrial unit heaters are available either with units made with plastic (EPP- expanded polypropylene) casings which ensures a modern design with high performance parameters, with outputs from 5kW to 70kW, and air flows up to 4,100 M3/hr or with metal casings with outputs from 6.5 kW to 344 kW in output.

These warm water supplied unit heaters can either be suspended from the ceiling or wall mounted, allowing you to expel the warm air either vertically or horizontally to suite your site requirements

Some of our industrial unit heater range can be supplied with drip pan and drain which means they can be used not only for heating, but also for cooling applications, when supplied with a chilled water supply.

For full information on the range of water fed industrial unit heaters , please see this page of our website –

Industrial electric unit heaters

We do two ranges of industrial electric unit heaters, the first range which in reality is also suitable for commercial applications, is available with outputs from 6 kW to 15 kW. The 6 kW unit is available in either single phase or a three-phase powered model. The electric unit heaters that have a 9 kW, 12 kW or 15 kW output can only be powered by a three-phase electrical supply. This range of commercial and industrial electric unit heaters is controlled by a wireless controller, which can control any number of our electric unit heaters, up to 100 metres away from the controller location. This saves on the associated wiring and installation costs of these unit heaters.

More information and detail on this particular range of electric unit heaters can be found here –

The second range of our industrial electric unit heaters are ideally suited to industrial premises, and are not wireless controlled. They should be used to electrically heat industrial areas with relative humidity of no more than 95% and an air dust concentration of up to 3mg/m3. They come with either a slot air diffuser as standard or can be fitted with a cone air diffuser which increases the range of the warm air stream. This range of electrically powered industrial unit heaters can be installed in either a horizontal position as a ceiling mounted unit heater or in a vertical position as a wall mounted electric industrial unit heater.

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Industrial electric unit heaters from Flexiheat UK

This range has of industrial electric unit heaters, has a large range of accessories, such as roof or wall air intakes and air mixing boxes that allow the unit heater to be supplied with a mixture of fresh and recirculating air to these industrial units. They also have a range of temperature controllers that automatically changes the heat output depending on the temperature in the room and a time programmer for control of unit’s operation in a weekly mode.

For more information and detail on this particular range of electric unit heaters can be found here –

Unit Heater Types – Gas,Oil, Diesel, LPG and Propane Fired Heaters

These differ from the unit heaters mentioned previously as all of these industrial unit heaters have a combustion chamber within the heater, where the fuel is burnt and thus the heat is generated within the heater itself. They are designed for horizontal wall mounting or in vertical suspended configuration, which is useful if you are short of floor space to install a heater, or should you just want the heater up and out of the way. They have as standard an axial fan for free blowing heating applications or can be fitted with a centrifugal fan, that allows duct work to be attached to the heater, and this duct work channels the heat to the desired areas with the building.

Industrial gas unit heaters;industrial gas fired unit heaters

Industrial gas unit heaters, available in either natural gas or LPG/ propane fired from Flexiheat UK

The gas powered unit heaters , (be it natural gas or LPG / Propane) details and further information can be found here-

industrial oil unit heaters

Industrial oil unit heaters

And for the oil / diesel fired unit heaters – pictured above , the full information is here –

Industrial steam unit heaters

Steam as a medium is often seen as an old type of heating system, as it is often associated with the industrial past , but with many industrial factories using steam as part of their process – this steam is a great way of heating an industrial building , as it is exceptionally good at transferring the heat from the steam into warm air and with exceptionally fast warm up times to. Industrial steam unit heaters are very similar to water fed unit heaters, in that they have a heat exchanger coil , casing and fan assembly, but in the instance of a steam powered unit , the heat exchanger or coil itself is designed to changed the steam vapour into usable warm air energy , in in this process the steam often condenses as it transfers it energy into the air. The coils or heat exchangers used in industrial steam unit heaters must therefore be manufactured from steel with a bi-metal fin assembly to accommodate the higher pressures and temperatures associated with steam. We do a full range of steam unit heaters that have an output from 14.6 kW to 459 kW in output, depending on your steam pressure available and the entering air temperature. full detail on the range is here –

Industrial steam unit heaters

Industrial Steam Unit Heaters from Flexiheat UK

Requiring little maintenance, these steam powered industrial unit heaters are extremely tough and highly efficient, and are often wall mounted

Flexiheat UK – Your Unit Heater experts 

As you can see, we do a full range of industrial unit heaters, powered by various fuel sources, so if you have a requirement for heating an industrial or commercial building, then we will have a unit heater option to suit, so please don’t hesitate to contact us at Flexiheat UK