commercial gas boilers; commercial lpg boiler; wall hung gas commercial boilers; commercial boilers in cascade; Worcester; price; vat; job;Flexiheat UK

Commercial gas boiler range – 50kW to 960kW heat output

commercial gas boilers; commercial lpg boiler; wall hung gas commercial boilers; commercial boilers in cascade; Worcester; price; vat; job;

Commercial gas boiler range – Condensing from Flexiheat UK


Commercial Gas Boilers – Available from 50kW to 120kW as single Boilers or up to 960kW in a cascade configuration for heating or and hot water heating via indirect cylinders. Commercial boilers work in exactly the same way as domestic boilers, but are designed and manufactured to efficiently cope with the higher hot water and heating demands of a commercial premises or business.

Our commercial boiler range all benefit from a stainless steel heat exchanger and condensing technology to maximise the efficiency of the central heating or heating and hot water, for your commercial heating applications. With stainless steel heat exchangers as standard, which carry a 5 year warranty ( terms apply) your heating, be it radiators or an underfloor heating system and your hot water production is in safe hands with our commercial boiler range.

This gas condensing boiler range can also be floor standing boilers, when using our frame kits or more commonly are installed as  wall hung boilers – the choice is yours to suite your site requirements.

Gas condensing boiler

These highly efficient commercial boilers are available in both a natural gas boiler and LPG for the full range, with various commercial boiler models with an output range from 50 kW to 120 kW, in a wall hung or floor mounted when mounted on our free standing or floor standing frame kits configuration. Making them the ideal boilers for commercial heating in any commercial premises or commercial business.

These wall hung boilers work in a fully modulating range, which provides energy saving through 1:10 modulating operation for 50kW and 60kW products commercial boilers.

50kw and 60kw gas commercial boilers from Flexiheat UK

50kw and 60kw gas commercial boilers from Flexiheat UK


and 1:20 for models 75kW, 100kW and 120kW wall hung boilers. As the larger units have 2 heat exchangers within the one casing, should one unit fail, you have 50% of your heating requirement still operational. You can also service one of the units when the other is still operational- so your heating system is never down .This is an important feature and benefit for this boiler range.

75kw to 120kw output gas fired wall hung boilers or floor standing boilers when a frame kit is used Flexiheat UK

75kw to 120kw Output gas fired wall hung boilers or floor standing boilers when a frame kit is used


These gas condensing boilers can be installed directly on the wall thanks to their reduced size and low weight, freeing up valuable space inside the boiler house of your commercial property or business.

These are modular boilers with condensing technology , and can be coupled together in a commercial gas boiler modular configuration which you can think of as multiple boilers within “One Total Boiler” as such, this give this range of commercial boilers , a few distinct advantages when compared to others, in that – If one system boiler goes down or malfunctions, you still having the remaining modules to provide you with heat, thus increasing reliability , which can be vital in applications like nursing homes, hospitals or any other commercial applications where your require constant heating and hot water.

Furthermore, multiple boilers, when in a cascaded configuration have power control boards that communicate between them and handle the power output of every module in a uniform and coordinated way in order to guarantee the maximum heating efficiency, matched to the water heating requirement of the installation.

The performance of this commercial boiler range with a wide range of power outputs makes it one of the best gas condensing boilers to use in any commercial boiler installations, be it feeding radiators, radiant panels, fan-coils, underfloor heating etc and to install in any boiler house, in either new or when replacing existing units in any buildings, houses, hotels, schools, factories, or any other industry etc.

With low class leading NOx Class 6 levels for all these commercial wall hung boilers ensuring maximum BREEAM points, which is important for any UK business interest, and something to be expected from leading manufacturers at this date

Gas Commercial Boilers – Compare the Range & Benefits

  • INNOVATIVE DESIGN, COMPACT, POWERFUL, & LIGHTWEIGHT – The devices have been developed and manufactured to be “space-saving”; thanks to their vertical structure they allow space savings in both new installs and to upgrade or replace older failed units or replacing an oil fired system boiler ( or even steam). Due to their light weight they are easy to carry , place and mount. Thus easy to install.
  • Stainless Steel condensing boilers that optimizes the output according to real thermal needs of the installation and business, ensuring maximum efficiency with a working pressure of up to 3 Bar
  • WIDE MODULATION OR TURN DOWN RATIO -wide modulation or turn-down ratio of 1:10 for the 50kW and 60kW and 1:20 for the 75kW, 100kW and 120kW units and up to an incredible 1:160 in cascaded configuration installation of 960 kW for example.
  • STAINLESS STEEL HEAT EXCHANGERS -Each heat exchanger is made without welded joints and is 28mm diameter in size with a industry standard working pressure of 3 bar.
  • ECOLOGIC PREMIX BURNER -The full range of boilers is equipped with ecologic premix burners made of Fecralloy metal fibre.
  • This range of condensing commercial boilers are suitable for use on sealed systems that fill from a mains water supply and open vented installations ( with a minimum of 0.3 Bar Head) and perfect for both new and retrofit installations.
  • Standard spares consent – all leading brands i.e. Wilo pumps, Honeywell gas valves etc
  • Suitable for radiators or under floor heating systems
  • Domestic hot water can be generated via an indirect hot water cylinder, all controlled via the boiler or via heat interface units (heat interface units are very common in blocks of flats – with a communal commercial boiler in a plant room)
  • These commercial boilers work in a similar way to domestic boilers – so proven reliability and performance.
  • We also do a combination version, which is listed here on our website here-

Commercial combi boilers up to 100kW or a dedicated webpage for our most popular 50kW combi boiler that we supply.

Why choose our Commercial Natural Gas Boilers –

High efficiency and fuel savings at the right price solution for your business

Condensing Boiler Technology

Total flame modulation

Certified efficiency up to 109%

Cascaded sequence control and heat exchangers in rotation – a solution for industrial applications


Quiet in operation

Easy installation and maintenance – in the rare occurrence of a breakdown – access to all essential system components

Reduced size and weight

Construction Quality

Modern, innovative and attractive design to keep your customers happy

large water ways the range benefit from a stainless steel heat exchanger, with industry leading dimensions

Turn down ratio up to 1:20

Ecology / Ecological

Fecralloy fibre premix burner

Reduced gas emissions in the atmosphere

Low CO and NOx levels – Class 6 -industry leading

Wall Hung Gas Boilers – for commercial applications or industrial

The 50kw to 120kW output commercial boilers. The R1K range of commercial boilers , which benefit from high efficiency with premix condensing technology. The technical details of these units are –

50 to 75kW Boiler models – commercial

50kw 60kw and 75kW gas boiler technical data for wall hung boilers – Flexiheat UK

50kW,60kW and 75kW Gas boilers technical information continued


50kw to 75kW gas fired boiler technical data from Flexiheat UK; job;

100 & 120kW Boiler models  – commercial

100kw and 120kw gas boilers technical data from Flexiheat UK

100kW and 120kW gas boilers technical information continued

100kw and 120kw gas boilers technical output information from Flexiheat UK:gas condensing commercial boiler;high efficiency boilers

Gas supply requirements and Flue system details for 100kwe and 120kW Gas Boilers



For the complete technical data on our boiler commercial range to suit your site services, be it Natural Gas or LPG , Please click on the following –

Download Flexiheat R1K Internal 50-120kw gas fired condensing commercial boiler manual

Boiler Control Options

All units can be controlled by an “OpenTherm” compatible controller ,with options for mobile phone control or we can supply a 0-10 Volt connection kit suitable for BMS connection, that is often required in commercial heating and plumbing applications or industrial premises.

Commercial boiler installations in cascade natural gas or LPG

This commercial gas boiler range can be used in a cascade configuration of up to 8 boilers , with the potential of 960 kW of heat output, making them the perfect boilers for Schools , Hospitals , Hotels, or any commercial or industrial site that requires heating via a hot water system. With a turn-down ratio of up to 1:160, these commercial boilers are the ideal boilers when you want to match your heating load, at the very best efficiency levels , giving you the lowest gas costs / gas usage for your commercial heating.

commercial and industrial gas boiler; commercial boiler in a cascade;commercial boiler installations

Commercial gas fired boilers from Flexiheat UK up to 960kW of output – free standing floor standing boilers in natural gas or propane

Easy to assemble pipe work kit for fast install on site for this commercial boiler range to make a floor standing commercial boiler set up.

Commercial Boilers for sale UK and Ireland

To ensure you get the correct commercial gas boiler in either natural gas or LPG, that is right for your water heating requirements, our sales team are here to provide information and advice to help you make an informed decision for your project requirements . With high operational reliability that you would expect from a leading brand that you as a customer can rely on, please call 01202 822221 to connect to our sales team or use our website contact form, to get the latest offers and price.