Survey, design, temporary heating, installation, commissioning and handover records for schools, care homes and commercial buildings across Surrey and the surrounding counties. One team from Farnham runs the whole replacement.
Replacing commercial boiler plant means taking the heating out of service, removing the old plant, installing the new plant and bringing it all back into use, cleansed and commissioned, before the building needs it. In a school the calendar sets that window. In a care home or a theatre the heating may have to keep running throughout.
We plan the whole replacement as one continuous programme: survey, design, temporary heating, strip-out, installation, commissioning and handover. The same team handles the gas service alterations, flue, controls and builders work, so one contractor is accountable from the first visit to the handover file. If the boilers are one part of a wider plant room or multi-discipline project, see our mechanical services page.
Gas work is carried out under our Gas Safe registration, number 629080. If you smell gas, turn off the supply if it is safe to do so and call the National Gas Emergency Service on 0800 111 999 before contacting us.
ComGas Services UK Ltd
Gas Safe · OFTEC · REFCOM F-Gas · CHAS · Constructionline
Each stage is part of the same programme. We confirm the scope of every stage in writing before work starts.
We survey the plant room, gas supply, flue route, controls and access before anything is specified. That includes how the old plant comes out, how the new plant gets in and what the building needs to keep running during the works.
Condensing boilers run at lower flue-gas temperatures and produce condensate, so an old flue is rarely suitable to carry over. We design the flue and the controls with the boilers, so the new plant is commissioned as one system rather than left working against controls inherited from the old one.
If a building cannot go without heat, we arrange temporary boiler plant for the works. At New Wimbledon Theatre a 500 kW temporary boiler ran in the car park while the permanent plant was replaced. At Hatch Mill Care Home the works were phased so heating and hot water ran throughout.
We strip out and dispose of the old plant, alter the gas service and install the new boilers, flue, pumps, pipework and controls. Builders work and making good the roof around the flue are part of the same package, not left to a following trade.
The system is cleansed before commissioning. Then the boilers, pumps, valves and controls are tested and commissioned. At New Wimbledon Theatre, manual, automatic and fault conditions were checked before handover.
Each replacement is handed over with record documentation for your building file. For gas boiler plant, that includes a CP15 record for the new boilers and a CP16 record for the testing and purging of the gas pipework.
A cascade is several smaller boilers working together as one heat source. It matches output to demand, so the plant is not running one large boiler at low load on a mild afternoon.
It also builds in redundancy. If one boiler is out of service, the others keep the building warm. That is why the new plant at Hatch Mill Care Home was configured as a cascade: in a care home, keeping heating and hot water running while a fault is fixed is a resilience requirement.
Education
The school’s main plant room replaced within a three-week programme: gas service alterations, new condensing boilers, a designed flue and new controls.
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Education
A six-week plant room rebuild, with the room’s air supply and electrical distribution renewed alongside new condensing boilers, flue and controls.
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Care & Healthcare
Boiler plant replaced with a new cascade arrangement in one week, with heating and hot water kept running in an occupied care home.
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Leisure & Hospitality
Three Hamworthy Purewell commercial boilers with new flues, pumps, gas safety systems and controls, and 500 kW of temporary heating during the works.
View projectGenuine reviews from ComGas customers, submitted through Google.
Rated 5.0 out of 5 from 75 Google reviews.
"Really happy with the service! Matt came out to carry out our boiler service and was friendly, professional and did a great job."
Kerryann, Google review, September 2026
"First time we've used this company and it won't be the last. Very professional and efficient in everything they do…"
Ian, Google review, June 2026
"…ended up coming to my place of work and sorting an old heating system that hadn't worked for years in a car showroom & workshop. Great team of guys"
James, Google review, October 2025
If your boilers are due for replacement or have failed, call us or send the details and we’ll advise on the next step.
Call 01252 214120It depends on the plant and what else the plant room needs. Recent ComGas replacements took one week at Hatch Mill Care Home, three weeks at Send CofE Junior School and six weeks at Our Lady of the Rosary School, where the air supply and electrical distribution were renewed too. You get a programme after the survey.
Yes. School replacements are planned for the holidays where possible, so the heating is out of service only while the building is empty, and the new plant is cleansed and commissioned before pupils return. If the work cannot wait for a holiday, the sequence, isolation and access are agreed with the school before work starts.
If it needs it, yes. We can install temporary boiler plant, as at New Wimbledon Theatre, where a 500 kW temporary boiler ran in the car park. In occupied buildings we can also phase the works so heating and hot water keep running, as at Hatch Mill Care Home.
We strip out and dispose of the existing plant as part of the job. Redundant items such as old feed and expansion tanks, flue headers and pipework can come out at the same time, so they are not left in the building.
Record documentation for your building file. For gas boiler plant, that includes a CP15 record for the new boilers and a CP16 record for the testing and purging of the gas pipework.
Turn off the supply if it is safe to do so and call the National Gas Emergency Service on 0800 111 999 before contacting us.
Send the details of the building, the plant and when the work needs to happen. We’ll arrange a survey and recommend the next step.
Current accreditations and registrations.
Message the ComGas office on 01252 214120.