No heating, no hot water, or a boiler showing a fault code — we diagnose the actual cause before quoting any repair, and give honest advice on when repair still makes sense. Gas Safe registered engineers covering Farnham, Guildford, Godalming, Farnborough, Fleet and Camberley.
This page covers boiler and central heating faults — a system that was working and has stopped, or is not performing as it should. That includes the boiler itself, the pump, valves, radiators and controls it drives as one heating system, because in practice a fault in one rarely stays isolated from the rest.
This is for homeowners with a boiler or heating fault needing prompt, honest diagnosis, and for landlords and letting agents responding to a tenant repair report where a clear explanation is needed for the tenant and the property file. If you're planning ahead rather than dealing with a current fault, see Boiler Installation & Replacement for a new boiler, or Boiler Servicing for planned annual maintenance.
ComGas Services UK Ltd
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For when something has already gone wrong and you want an engineer to look at it.
The same symptom can have several different causes. We diagnose which one applies to your system before quoting any repair, so you know what you're paying for and why.
A fault code or symptom narrows down the likely cause, but it doesn't confirm it on its own — that takes a proper inspection.
We don't quote a repair from a description of symptoms alone. An engineer reads any fault code and error history, checks system pressure and pump operation, and inspects the components most likely to be responsible before confirming what's actually wrong.
Repair timescale depends heavily on whether the part is a common component readily sourced, or a model-specific part for an older or less common boiler. We check availability as soon as a fault is confirmed.
Some faults sit in the heating system rather than the boiler itself. We treat these as part of the same repair visit where they're the actual cause of a heating problem.
Not every fault is worth fixing on an older boiler. We'll tell you plainly when a repair is a reasonable fix and when it's a temporary one on a boiler approaching the end of its practical life.
The cause confirmed before a repair is quoted
We don't quote a repair from a description of symptoms alone, because the same symptom can have several different causes. An engineer attends, reads any fault code and error history the boiler has recorded, checks system pressure and pump operation, and physically inspects the components most likely to be responsible before confirming what's actually wrong.
Only then do we quote the repair, so you know what you're paying for and why, rather than paying for a guess. Repair timescale then depends heavily on whether the part needed is a common component readily sourced, or a model-specific part for an older or less common boiler — we check availability as soon as a fault is confirmed and give a realistic timescale rather than an optimistic one.
Reviews from real ComGas customers, shown as 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 boiler already has a fault, such as a lockout code, no heat or low pressure, it should be booked as a diagnostic repair visit.
Call 01252 214120Fault codes point towards the general area of the problem — ignition, water pressure, a sensor, or the fan, for example — but they don't confirm the exact cause on their own. We use the code as a starting point for diagnosis, not a substitute for it, and confirm the actual fault before quoting.
This pattern usually points to a diverter valve or a specific sensor fault rather than a boiler that's failed completely, since the boiler is clearly still firing and heating water. We diagnose which component is actually responsible before quoting a repair.
It's worth having checked. Kettling — a banging or rumbling sound — is commonly caused by limescale or sludge restricting flow through the heat exchanger, and left unaddressed it accelerates wear and can lead to a more expensive failure.
Repeated pressure loss almost always means there's a leak somewhere in the system, even a very small one, rather than a fault with the pressure gauge or the boiler needing repeated topping up as routine. We trace the source rather than just repressurising it each time.
It depends on the boiler's age, the part needed, and its recent fault history. We give an honest view during diagnosis — a young boiler with one fixable fault is usually worth repairing; an old boiler with a costly part and a history of breakdowns usually isn't. See Boiler Installation & Replacement if replacement looks like the better route.
We prioritise genuine no-heat and no-hot-water faults, particularly in cold weather, ahead of routine work. Exact attendance time depends on current workload and location, which we'll confirm when you call.
No. This page covers diagnosing and fixing an existing fault. Planned annual maintenance — checked and recorded before anything goes wrong — is covered on our Boiler Servicing page.
Turn off the gas supply and call the National Gas Emergency Service on 0800 111 999 before contacting us. We'll talk you through the necessary safety steps over the phone.
Three straightforward options for domestic gas boilers and heating systems. Every price includes VAT, and parts are charged separately on all three.
£99inc. VAT
For when something has already gone wrong and you want an engineer to look at it.
Parts, materials and any labour beyond the first hour are charged separately. We explain further chargeable work before going ahead wherever it is practical to do so.
Recommended
£11.95per month inc. VAT
12 monthly payments£143.40
Annual servicing and extra heating support in one simple monthly plan.
Parts and additional repair labour are charged separately. Out-of-hours attendance is not included. This is a service and maintenance plan, not breakdown insurance.
£109inc. VAT
One-off annual servicing for a single domestic gas boiler.
Servicing only. If we find a fault, we explain it and quote for the repair separately.
| What you get | Boiler & Heating Repair Visit | ComGas Heating Care | Annual Boiler Service |
|---|---|---|---|
| Attendance for a heating fault | Included | Included | Not included |
| Annual boiler service | Not included | Included | Included |
| Heating System Health Check | Not included | Included | Included |
| Written service record | Not included | Included | Included |
| One included repair visit each year | Not included | Included | Not included |
| Annual service reminder | Not included | Included | Not included |
| Replacement parts | Not included | Not included | Not included |
| Additional repair labour | Charged separately | Charged separately | Charged separately |
| Out-of-hours or 24/7 attendance | Not included | Not included | Not included |
| How you pay | Once, per visit | Monthly | Once a year |
All prices shown include VAT and apply to one domestic gas boiler. Replacement parts and materials are charged separately in every case.
Tell us what the boiler is doing — or not doing — and we'll get an engineer diagnosing the actual cause.
Current accreditations and registrations.
Message the ComGas office on 01252 214120.