Commercial Combi Boilers – 4 kW to 100 kW Output – Gas Fired

 

Commercial combi boilers or commercial combination boilers, whichever you want to call them, are generally considered to be the United Kingdom’s most popular type of boiler. A commercial combi boiler, or combination commercial boiler, is a very compact and highly efficient commercial boiler that not only supplies all the central heating requirements but also the hot water for sanitary use, such as bathing or showering, washing up, food preparation, hand washing, etc., for many applications, such as larger households to commercial applications / commercial premises / commercial property.

They ensure not only significant savings on installation costs but also guarantee lower running costs too, making them the best choice for many larger domestic properties or commercial heating requirements where heating and hot water are required. These boilers are either wall hung- or floor-standing condensing combi boilers (with a freestanding frame kit) that can be fired with either natural gas or LPG (propane). This full range of condensing boilers provides high-efficiency energy generation with their “Premix Technology” and “Condensing Technology” for heating and hot water production for commercial buildings.

COMBINATION COMMERCIAL BOILERS

A combination boiler combines a water heater and central heating boiler in a compact unit and usually uses a plate heat exchanger to produce the domestic hot water. When a hot water tap is turned on, the boiler sends the heat produced from the heating side of the boiler, via a control valve, to the plate heat exchanger, which then heats up the domestic hot water until the hot water tap is turned off.

These combi boilers can use the heat they produce for either the central heating system or the domestic hot water system for your commercial premises.

One potential issue with a commercial combi boiler is that it requires sufficient mains water pressure to achieve adequate hot water flow rates and a sufficiently large plate heat exchanger to do so. We classify these units as “a true commercial combination boiler”

If you have a low mains water pressure and flow rate, then it can result in your hot water flowing out at merely a trickle, meaning showering becomes a poor experience or filling a bath literally takes forever.

So, you need to ensure you have an adequate cold water mains flow rate to meet your hot water requirements.

We at Flexiheat UK have overcome these potential problems by producing a combi boiler for commercial use, which can be supplied with cold water from either the mains supply or a cold water storage tank, provided you have the adequate head/pressure available – the minimum should be at least 1 bar or 10 metres of head, but we recommend 2 to 3 bar for useful water pressure.

Commercial Gas Combi Boiler -Features and Benefits

1. Compact size – A commercial combination boiler is very compact (wall hung or floor mounted), having a small footprint when compared to the older traditional boiler and indirect cylinder setup found in commercial heating and hot water applications.
2. Reduced installation time and cost – Also because they are mains water-fed, there is no need for a cold water storage tank in the roof or loft space, which benefits with lower installation costs, as less pipework and labour time are required to fit one of these boilers whilst removing the potential of these pipes or water tank freezing in the British winter period – another benefit.
3. Excellent efficiency – These commercial combi boilers are up to 109% efficient when working on a 30% heating load at 30 degrees C (typically an underfloor heating system) and up to 98% efficient at the minimum load when used on an 80/60 degrees C heating system (typically an older radiator-designed system). Heating a larger home or commercial building with a commercial boiler with condensing technology is, therefore, more affordable and has low emissions when compared to conventional non-condensing boilers.
4. Adjustable kW output – You can set the commercial boilers to have a maximum power output, for example. Then the unit will modulate up and down its output range to your specified maximum kW output.

The 50kW commercial combi boiler can be set up to any figure up to 53kW of heat output for the central heating (on a 50/30°C flow and return system); thus, it can be a 40kW combi boiler, a 42kW combi boiler, a 50kW or even a 52kW, etc., whatever your requirements are for these condensing boilers, as they can be down-rated to suit your requirements. This 50 kW combi boiler has its own dedicated webpage – see here for more information – 50kW gas fired combi boiler

The 60 kW Commercial combi boiler – can be set up to any figure up to 62.84 kW of heat output for the central heating (on a 50/30°C flow and return system); thus, it can be a 60 kW combi Boiler, a 55 kw combi boiler, etc.

The 70 kW Commercial combi boiler – can be set up to any figure up to 79.35 kW of heat output for the central heating (on a 50/30°C flow and return system); thus, it can be a 60 kW combi boiler, a 55 kw combi boiler etc.

The 100kW model has an output anywhere from 5.29 to 106.80 kW heat output at 50/30°C flow and return for the central heating.

This feature gives you maximum flexibility and can also future-proof your combination commercial boiler should you wish to add to your property or premises in the future and require more heating power output for your project requirements.

Commercial gas-fired combination boilers

A commercial combination boiler utilises a P.H.E. to produce domestic hot water, meaning it has no water storage element; these boilers can be wall-hung or floor-standing for commercial premises.

This commercial boiler range is designated the “RK range” and is available in either natural gas or LPG. These are available in the following sizes

A) A 50kW version – whereby the plate heat exchanger is integral to the boiler casing – This boiler is a modulating boiler with a power range of 5.29 to 53.40kW output at 50/30°C flow and return or 4.83 to 49.19kW at 80/60°C with 20.30 litres/min of domestic hot water with a temperature rise of 35 degrees Celsius.

This 50 kW combi boiler has its own dedicated webpage here – 50 kW combi boiler 

B) Alternatively, a 60 kW, 75 kW, or 100 kW output option is available; in these models, the plate DHW heat exchanger is mounted directly underneath the boiler, above the low-loss header (see picture below).

 

The 70kW model is a modulating commercial boiler with a heating output range of 3.87 to 79.35 kW  at 50/30°C flow and return, or 3.5 to 72.83 kW at 80/60°C, providing 30 litres/min of domestic hot water with a temperature rise of 35 degrees C. These can be either wall-hung or floor-standing boilers when using our frame-mounting kit, as shown in the picture above.

or the 100kW model – again, this commercial boiler is a modulating boiler with a heating output range of 5.29 to 106.80 kW at 50/30°C flow and return or 4.83 to 98.37 kW at 80/60°C with 40 litres/min of domestic hot water with a temperature rise of 35 degrees C. These can either be wall-hung boilers or floor-standing boilers when using our frame-mounting kit

Both of these gas commercial combi boilers mentioned above have a modulation ratio of 1:20 for greater efficiency and reduced consumption both in heating and in DHW production. These units have stainless steel heat exchangers as standard, and they have two heat exchangers or boilers within one casing, so if one fails, you still have 50% of your duty available. Another benefit is that you can service one boiler while the other is working, so there will never be any “downtime” for your heating or hot water system, which is a great feature!

Commercial Gas Combi Boiler Range

Heating and domestic hot water thermal capacity of  50 kW to 100 kW central heating outputs – wall-hung or floor-standing boilers with the use of the free-standing boiler kit

Environmentally friendly with low emissions – Class “6 NOx” and CO emission rates for these condensing commercial boilers.

Prolonged high performance and high thermal efficiency with condensing technology, as the boiler features a stainless-steel heat exchanger with enlarged pipe diameters of 28 mm.

The comfort and usability of rapid hot water generation via our highly efficient plate heat exchanger these floor-standing boilers

A high modulation ratio of up to 20:1 means these commercial combination boilers adapt to the heat output required to suit the site conditions and elements.

Low operational noise levels and heat losses thanks to its configuration with high heat and sound insulation.

The ability to operate with Natural Gas or LPG (Propane Gas)

High-efficiency circulation pump with automatic air purge, controlled via a PWM driver.

Simple control with an easy-to-use illuminated LCD panel; you can view error codes and boiler information on this panel.

The ideal boiler with superior safety features, such as
Flame safety control: ionisation.
Flue gas temperature control.
Heating circuit overheating safety.
Frost protection.
Low water pressure safety system

Optional room thermostat connection.
Optional remote control.

Hot Water Performance

Our commercial combination boiler uses a plate heat exchanger that is located just above the low-loss central heating header, as demonstrated by the picture below.

 

 

Alternatively, we do larger heat exchangers that must be mounted separately to the commercial boiler on the floor, normally for increased DHW performance.

Below is the hot water performance: our 75 kW boiler, with a flow and return temperature of 80/60°C on the primary side, will produce 2,100 litres of DHW when the temperature is raised from 15°C to 45°C per hour, which equates to 35 litres per minute.

 

which is very impressive domestic hot water performance indeed, as these combi boilers have a hot water priority system.

Flue options for these combination boilers

The full range of these commercial boilers can be flued in various ways. The most common is a coaxial flue system, which makes these combi boilers for commercial buildings room-sealed appliances, meaning that the combustion air (the air feeding the burner on the boiler) is brought in from the outside environment to the boiler.

These combi boilers can be flued in a co-axial system –

Horizontally- up to 10 metres in total length, with our 80/125 mm coaxial flue – the use of each 90° elbow reducing this length by 0.8 metres and the use of each 45° elbow reducing it by 0.5 metres.

or

Vertically – up to 10 metres in total length, with our 80/125 mm coaxial flue – the use of each 90° elbow reducing this length by 0.8 metres and the use of each 45° elbow reducing it by 0.5 metres.

Or these commercial combi boilers can also be flued in a “B23” configuration, whereby the waste flue gas discharge is ensured by a flue system terminating externally from the location of the commercial boiler, while the combustion air is absorbed from the location of the boiler. This is sometimes referred to as a conventual flue’d system.

In a single-wall flue system, these commercial combi boilers can be flued –

Horizontally – up to 30 metres in total length, with the use of 100mm diameter flue, each 90 ° elbow reducing this length by 1.5 metre, and the use of each 45 ° elbow reducing it by 0.8 metres

or

Vertically – up to 25 metres in total length, with the use of 100mm diameter flue – with the use of each 90 ° elbow reducing this length by 1.5 metres and the use of each 45 ° elbow reducing it by 0.8 metres

Combination Boiler Controls

These commercial combi boilers have an easy-to-operate control panel, which is an “OpenTherm Plus” protocol control panel, which basically means you can control these commercial combi boilers via the use of an OpenTherm controller, such as a “Nest” or “Hive” type or similar. We do our own version called the “Cloudwarm”, which is an OpenTherm controller.

This means you can make your life simpler and control these commercial combination boilers from either your mobile phone (Android or Apple) or your PC or tablet, from anywhere in the world as long as you have internet access. The control panel also has numerous built-in features such as

• Full protection against freezing of the heating and domestic hot water in low ambient temperatures
• Ability to operate according to different heat demands with the variable flow pump control
• Anti-blockage System – The circulation pump is activated automatically once every 24 hours and prevent any blockage
• 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
• Ability to control these commercial combi boilers by Android and IOS operating systems
• Can be controlled by a BMS system using a 0-10 volt signal via an interface card within the boiler.

 

Gas-Fired Combi Boiler – Heavy Domestic or Commercial

We often get asked when the classification of a commercial combination boiler starts. Well, there is no hard and fast rule. We look at this way –
A standard new build house in the UK will use a combination boiler that at most is 30 kW these days
However, a domestic gas engineer registered with Gas Safe can work on appliances up to 70 kW net, provided the gas system has a gas volume of less than 0.035 m³, a flow rate of up to 6 m³ per hour, and pipework with a diameter of 35 mm or less.

Therefore, it is almost better to classify these boilers’ suitability / applications by description –

Heavy domestic houses / larger properties

These would typically be the following: –

For 2 or 3 bathrooms, our 50kW combination boiler will typically suffice.
3 or more bathrooms – or a large hot water usage property / lifestyle – then you’re looking at the 100 kW combination boiler, as normally the central heating requirement for the property would be larger. So, these would typically be larger detached properties, such as mansions or large country houses.

On the Commercial property applications

You would be look at –

Doctors’ and dental surgeries’
Schools and colleges
Retail / shop outlets
Commercial and smaller industrial units
Bed and breakfasts establishments / Even smaller hotels

Anywhere there is high demands for central heating boiler

They can be used in any commercial heating application with a radiator or underfloor heating system or with warm air hot water unit heaters, which we supply for the commercial heating of small business units or warehouses.

Commercial boiler – Natural gas or LPG (propane) 

So if you require the best commercial combi boiler for sale on the UK market that can be used in either commercial premises / applications or even large properties for commercial heating, 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. Please follow us on social media for all our latest offers.