Gas Water Heaters

26th August 2022/in News /by flexiheat

Gas Water Heaters

A gas water heater or gas fired water heater is used to produce domestic hot water for your domestic properties e.g. flat, house or commercial property. This hot water is of sanitary quality and is used to feed showers, baths, and hot water taps or faucets. They can be mains gas (natural gas) or LPG gas fired.

Water heater gas fired

One of the many benefits of a gas water heater is the energy delivery that it can dissipate into the water and thus the good flow rates they can achieve when compared to instantaneous electric water heaters, which require a lot of Amps for heating water and normally a three-phase electric supply to achieve similar flow rates.

Gas fired water heaters

Our entire range of our gas water heaters can be powered by either mains gas (also known as natural gas) or LPG (propane gas), which is your liquid gas. It is easy to convert our high energy efficiency gas fired water heaters from one type of gas to another via a simple-to-fit gas conversion kit.

Hot Water Heaters

Gas fired water heaters can be split into two main categories:

On demand water heaters

On-demand, tankless water heaters or instantaneous water heaters will use less energy than storage water heaters and are the most energy-efficient method for heating water, with high performance mains pressure to all warm water outlets. However, the instant hot water flow rate demand and the usage of the hot water outlets by the customer installation must be considered to ensure they’ll work correctly. These gas water heaters are low NOx and cost effective and available in natural gas or LPG. We go into more depth on this range here – instantaneous gas water heater

Storage hot water heaters

Alternatively, we do a range of low NOx storage gas water heaters, which are condensing water heaters with high energy efficiency; the two stock units have a water storage quantity of 150 litres, which is ideal for customers with a larger demand for domestic hot water, such as having a periodic requirement for high volumes of water in a short period of time or intermittent times, that an instant hot water heater couldn’t service with its flow rates. You simply need to store water / storage systems for certain customers’ requirements in the most cost effective manner.

Storage gas fired water heaters with an inbuilt 150 lire stainless steel hot water tank energy efficient hot water heater from Flexiheat UK

Storage option – 28kW or 34KW output options

The “SFKA” range, as they are designated, is available in natural mains gas or as LPG as their fuel source and is available with an output of either 28kW or alternatively a 34kw output model.

They come complete with a 150 litre stainless steel storage tank, which has a long warranty, and all the associated plumbing pipework and a pump local within the casing.

internal picture of our hot water heater with storage tank which is gas fired from Flexiheat UK

SFKA 28 or 34 KW Output models – Natural gas or LPG powered

They also have easy access for service or to maintain this reliable water heater unit as the panels are removable-with loads of room to get at and checkout the plumbing components that connect the heat exchanger of the gas water heater to the storage tank. These gas water heaters are sometimes referred to as a gas hot water tank or cylinder, and are detailed on this webpage – gas hot water tank or cylinder in full detail.

Thermal efficiency

In any domestic or commercial hot water heating system, any gas fired water heaters used these days must not only be a reliable appliance but also as efficient as possible.

This is where condensing water heaters come in as a solution with regards to gas fired water heaters, as you can recover the latent heat from the heater’s flue gases and recover that energy via a heat exchanger back into the hot water temperature-and not lost to the flue gases and the environment whilst saving the customer money.

Gas fired water heaters in condensing mode as it extracts all the energy from the fuel

Gas fired water heaters – Because the flue gases leaving the water heater are cool, they form a visible mist or plume of water vapour whilst leaving the flue terminal point or location

Because of this condensing process, our condensing gas water heater range are at least 15% to 20% more efficient than non-condensing systems. With the current high cost of energy, any customer may save significantly on their water heating costs by the installation of a water heater that will condense, whether in a domestic or commercial application.

ErP A rated gas fired hot water heaters - contact Flexiheat - picture shows energy efficiency sign so the customer can make an informed decision

Thermal efficiency or energy efficient ErP rating – “A”

This type of water heater is ErP “A” rated-and due to recent legislation changes, you must now fit condensing gas fired water heaters in all new and retrofit commercial water heating systems. Please visit this location on our site for more in-depth information on this- Water heater legislation changes-Part L Building Regulations-June 2022

Gas water heater controls

You can use the thermostat built into the control panel on the gas water heater to set the hot water temperature output required, or alternatively, we do a remote temperature controller option too.

If you require any more suitable support, solution advice, check stock, delivery times or require a price on our gas water heaters from Flexiheat UK, then please use the contact us form page on the website, or alternatively feel free to give us a call on 01202 822221, as we sell direct to the trade and public customer base. Connect with us on Facebook or Twitter so you can contact us at any time.

Commercial Hot Water Cylinders or Calorifiers

16th August 2022/in News /by flexiheat

Commercial Hot Water Cylinders or Calorifiers

Commercial hot water cylinders or cylinder unvented or vented indirect water heaters 200 to 6000 Litres Flexiheat UK

Commercial domestic hot water cylinders or calorifiers from 200 to 6,000 Litres

Commercial hot water cylinders are designed to satisfy substantial or continuous domestic hot water demands such as hotels, care homes, schools, hospitals, camp sites, sports centres, leisure centres, residential or office blocks, when there’s a frequent requirement for large quantities of domestic hot water, in a short period of time, without any performance losses, when staff, residents or visitors create demand for warm water in commercial properties or commercial buildings.

Our commercial cylinders, tanks or commercial calorifiers as they are also known, provide a solution for large scale commercial domestic hot water capacity, with fast flow rates that satisfy even the toughest of demand requirements.

Commercial cylinders for commercial water heating

Commercial cylinders come in various options and can use various technology, such as solar (renewable heat energy), electricity, heat pumps or warm water thermal systems (again a renewable heat energy source) to power the domestic hot water cylinder. The two leading hot water cylinder water heating solutions or commercial cylinder options are:

Indirect – indirect commercial cylinders / calorifiers

Indirect commercial cylinders showing the coil which is used to heat up the DHW via a boiler, heat pump or solar heating system which transfers the heat to the water heating system

Indirect commercial cylinders – Showing the internal hot water heating coil

These are a storage commercial hot water cylinder, that are often powered by a traditional heating boiler that supplies the system, via a coil (which can be a single or double coil) or even a plate-to-plate heat exchanger for high warm water capacity solutions.

The cylinders, tanks or vessels stored hot water capacity can be from 200 litres up to 6,000 litres in system capacity, (any cylinders under 200 litres of stored hot water we classify as domestic sizes – but there is no hard and fast rule on this) although bespoke designed models can be produced to support any specific requirements your commercial project may have.

Factors such as available installation space, may come into consideration and it is possible to link up several smaller cylinders or buffer vessels to meet the required storage capacity for commercial buildings.

Our indirect commercial hot water cylinder range can be fitted with an electrical immersion heater or heaters, as a back up to your primary heating energy source such as a boiler, thus direct heating of the water in the commercial cylinder.

Direct – Direct commercial cylinders or Calorifiers

A direct commercial hot water cylinder is a unit that uses a heat or energy source that is physically located within the cylinder, normally this is an electric immersion heater or multiple immersion heaters, to warm the water – thus the term “direct water cylinder”. Normally the require three phase electric power rather than single phase supply service, as any immersion heater over 3kW requires a three-phase power supply. The immersion heaters have a control thermostat, that allows you to set your desired temperature.

Often used in commercial properties or a commercial project where there is no access to gas or oil, or more commonly with businesses or individuals who are using a renewable electric supply or buying electric that is produced by certified renewable sources – enabling them to have a carbon neutral domestic hot water system.

We have a dedicated webpage on our direct commercial cylinders, which are stainless steel cylinders on our website here –

Commercial Direct Electric Water Heaters

Materials of construction of hot water commercial cylinders

There are two main options for the construction of the vessels themselves – being

Vitreous enamelled coated mild steel vessels

Vitreous enamel protects the mild steel from corrosion. Due to its ability to interact molecularly with the mild steel surface of the tank, it can store domestic hot water at the highest temperature of 95 ºC without breaking down or coming off from the steel surface of the tank. All internal linings in domestic hot water commercial cylinders must, by law, be “food grade” (EC Regulation 1935/2004). Our vitreous enamel has food grade certification at the specified test temperature according to current regulations at 120ºC, which guarantees its maximum quality at extreme working temperatures, and is suitable and approved for potable water use.

Ultimately vitreous enamelling is a food-grade, impermeable coating with a porcelain appearance that protects the storage tank’s metal surface when it comes into contact with the stored hot water.

The range has evolved to the point that enamelled lined commercial cylinders now have the same working pressure of 8 Bar for the domestic hot water or even 10 Bar pressure (at special request) as their suitable stainless steel equivalents, but at reduced costs.

The other benefits are that they are more cost effective than a stainless steel vessels / stainless steel cylinders or buffer vessels range. The warranty period on this range is 5 years.

high performance indirect hot water heaters calorifiers 200 to 1000 Litres

high performance indirect domestic hot water calorifiers / cylinders 200 to 1,000 Litres

Technical details of the domestic hot water heaters

High performance hot water calorifiers or water heaters cylinder that come with a warranty details - Flexiheat UK

200 – 1000 Litre Calorifiers – The HLB option have a 400mm inspection and clean out manhole on the 800 litre and 1,000 Litre hot water storage models

commercial cylinders water heating performance from Flexiheat UK trading in England UK

Based on a primary inlet heating temperature of 85C

Continuous hot water flow rates at various input temperatures for 10C to 45C

Continuous hot water flow rates at various input temperatures from 10C to 60C

Cathodic protection should be installed in all DHW tanks composed of carbon steel with an inner lining to DIN 4753. A cathodic protection system consisting of sacrificial magnesium anodes and an anode charge metre is included as standard with this tank series.

Cathodic protection systems with sacrificial anodes must be monitored for wear on a regular basis and replaced, if necessary. You can upgrade to the special electrically powered titanium anodes that emit the necessary current for protection of the tank lining which means that, unlike sacrificial anodes, there is no wear and the anodes do not need to be replaced.

Industrial Hot Water cylinders – from 1,500 to 6,000 Litres

Details on the 1,500 litre to 6,000 Litre Industrial hot water cylinders / Water heaters

Industrial hot water cylinders water heaters from Flexiheat UK – 1,500 Litres to 6,000 Litres

Technical details

Download the Domestic hot water cylinders and storage vitreous enamelled units brochure from Flexiheat UK

We do a full range of commercial gas boilers to power this commercial hot water cylinder range – these are detailed here – Commercial gas boilers – floor standing, or wall hung.

Stainless steel cylinders

Stainless steel cylinders – This material has become popular over the years, as stainless steel has a much higher resistance to all forms of corrosion, including stress and crevice, making it highly durable and promising a longer working lifespan of the commercial cylinder.

Stainless Steel also can withstand extremely high pressure, which has paved the way for the unvented hot water cylinders that we see today. Unvented commercial cylinders have grown in demand due to their delivery of mains pressure hot water services.

These two factors have made this high-quality material the perfect solution for pressurised domestic water heating services.

Stainless steel commercial indirect hot water calorifiers from Flexiheat UK

Stainless steel commercial hot water cylinder range from 200 to 1000 Litres.

For full output data on our s/s commercial cylinders – please see pages 30 & 31 of the following brochure –

Download the Stainless Steel cylinders for domestic hot water production and storage brochure – Flexiheat UK

We also do a range of stainless steel buffer vessels too- Buffer vessels are used to store hot water either hot water for heating or how water for domestic hot water use -these are detailed on our dedicated buffer vessel webpage – look for the stainless steel options

Commercial unvented hot water cylinders

Unvented cylinders – provide mains pressure water directly from the cold-water mains. The cold water is directly drawn from the mains water supply, then heated by the relevant heat source that you supply to the coil of the commercial cylinders.

When using electric as your fuel to power the water cylinder they are referred to as – direct commercial cylinders unvented.

Or when powered by boilers which can be either gas or oil boilers, or even heat pumps these days for reduced running costs – they are referred to as an indirect commercial cylinders unvented.

Benefits of an unvented hot water system for commercial premises

• Maintain strong pressure thanks to direct mains supply – in that direct mains supply can have a pressure up to 10 Bar

• No cold-water feed and expansion tank (also referred to as the header tank) at high level – that would give the system pressure, is required

• Thus, an unvented cylinder doesn’t rely on gravity fill and be fitted in any location

• Enhanced hygiene quality and safety – a sealed system not only eliminates the risk of leaks or freezing of the header tank in colder conditions, also contamination of the tank is also removed.

Fast recovery commercial hot water cylinder?

We often get asked what are the fastest recovering commercial cylinders – and the answer is – This commercial cylinder range is -which are ideal for commercial properties or premises with high demands.

Commercial calorifiers

We have some of the best commercial hot water cylinder’s on the market, all designed to the highest quality standards, and with all the relevant safety features. All of our commercial cylinders are approved to the PED (Pressure Equipment Directive) and the approved Energy Related Products (ERP) Directive 2009/125/CE, where applicable.

Should you interest and require any more support, free design or selection advice or costs/ get a quote on our commercial hot water cylinder range then please use the contact us form page on the website, or feel free to give us a call on 01202 822221,to talk to our experts today as we sell direct to the trade and public.

Commercial Boilers

3rd August 2022/in News /by flexiheat

Commercial Boilers

Gas condensing boilers for commercial boiler installations

Commercial boilers are manufactured to fulfil the special needs of commercial premises or businesses or for heating apartment buildings with heat interface units, via a local heating network. Commercial boilers work similarly to domestic boilers, but they generate a larger heat output, making them suitable for commercial boiler installations.

Whether you are a professional heating engineer or a business owner looking to upgrade your boiler, this introduction about boilers with high energy-efficiency for commercial or even industrial heating will show you your options.

Our commercial boiler range has been designed and developed to meet a wide range of applications and project requirements from heating commercial stores, factories, schools, hotels, pubs, and leisure industry – just to name a few commercial heating applications with condensing technology to achieve the energy savings.

Commercial boiler systems

They are ideal boilers or perfect solution for producing domestic hot water as well as doing the heating system in a commercial property. This is achieved by using a boiler or even boilers in conjunction with suitable indirect hot water heaters or heat interface units. Making them a system boiler in this case.

Wall hung boilers

commercial gas boilers that are wall hung condensing devices from Flexiheat UK

Gas boilers – wall hung boilers with condensing technology for commercial heating

Wall hung gas condensing boilers are the most popular units these days for commercial buildings – especially in reference to commercial gas boilers, as they are the ideal boilers to fit in relatively small boiler houses and are easy to cascade to suit any project.

Commercial gas boilers in cascade offer higher modulation ratios, and when you bear in mind that commercial boilers spend 70% of their time at 30% of heat output, and the other 30% of their time at full output range, commercial gas boilers that have a high modulation ratio support these demand cycles.

The result is longer run times with lower cycle rates as the boiler controller operates the required number of commercial boilers or boiler to meet the heating demand of the system, which also reduces the wear and tear on boiler installation as continually cycling on and off can result in early failure of gas valves, fans and pumps fitted to the boiler or heating system.

We supply a full range of high efficiency commercial gas boilers, with modulation figures for single piece boilers of 1:20 and when used in cascade, with a maximum kW output of 960kW, so we can cover or fill any industrial or industry heating requirement as well as commercial applications.

Commercial floor standing boilers are still a very popular installation in the UK, floor mounted boilers are available as gas fired either natural gas or as an LPG condensing boiler , electric or oil fired condensing boiler ranges with some very large outputs.

Commercial floor standing boilers

Commercial floor standing boilers or free standing boilers are still a very popular installation in the UK for commercial applications, floor standing boilers are available as gas fired either natural gas or LPG, electric or oil-fired ranges with some very large outputs. There are various subject options –

Gas-fired floor mounted boiler range

industrial gas boilers for heating Flexiheat UK

Gas condensing commercial and industrial range – stainless steel heat exchangers

Our gas fired floor mounted commercial gas boiler range is detailed more on the following webpages – Commercial gas boilers – floor standing, or wall hung up to 960kW of output power or our commercial and industrial gas fired floor mounted boilers – which you can install up to 12,160 kW of heating power – which is a large amount of heat ! and enough to cover any installation requirements from one of the leading brands of gas condensing boilers for industry or commercial applications.

Oil fired floor standing commercial / industrial heating boilers

commercial and industrial floor standing condensing oil boiler also available as a dual fuel commercial boiler - oil and gas

Also available as a dual fuel commercial boiler – oil and gas fired

Commercial oil fired boilers, that are floor standing start at 70kW and go all the way up to 1,550 kW in condensing oil fired boilers – the UK and European legislation states that all boilers from 70kW to 400kW must be condensing to meet the Energy Related Products Directive requirements for heating systems for commercial premises. See this webpage for more information on our commercial floor mounted oil boiler range.

But it would be foolish not to use condensing technology above the stipulated 400kW, as condensing condensing technology is 20% more efficient than a non-condensing boiler, and benefit from low emissions. Again, they can produce domestic hot water through our commercial hot water indirect cylinders or heat interface units.

Frequently asked questions

Here’s some frequent questions we get

What are commercial boilers?

Commercial boilers are widely used to heat structures such as offices, schools, blocks of flats, and local surgeries or hospitals etc. They typically create hot water using either gas, electricity, or oil as a fuel source. This heated water is used to power the heat emitters in the building, such as underfloor heating, radiators, or fan coil units.

What size is a commercial boiler?

Gas and oil-fired commercial boiler range in size from 70kW to 2,000 kW plus. This wide range of output capacities helps to guarantee that businesses may select products that fit their individual heating and hot water requirements.

Commercial boiler prices UK

If you require any further support, advice, latest offers of our commercial boilers range, be they floor standing or wall hung models then, please contact us via our email contact form above on the website or call our business sales services team direct on 01202 822221 and deal with your commercial project interest. Sign up and follow us on Facebook and twitter for our latest news.