It's important to check that your boiler is fully functional to keep you and your home warm. A faulty or badly maintained boiler can be Extremely Dangerous and can even kill.
A boiler problem is an inconvenience and while some boiler issues can be addressed without the need to call a professional, sometimes an experienced heating engineer will be required. Even if you do take care of your boiler, problems can occur despite your efforts.
We’ve listed some of the most common boiler problems:
Boiler Turns Off
Cause:
This can happen for a number of different reasons, including low water pressure, thermostat issues, or if you have a frozen condensate pipe, air in the system or a faulty pump.
Pilot Light Keeps Going Out
Cause:
The most common reason for this happening is a faulty thermocouple, although it can also be caused by damaged seals.
Noisy Boiler or Noisy Central Heating
Cause:
A noisy boiler is often caused by “Kettling”, which is a build up of limescale in the heat exchanger. Banging, gurgling, rumbling or whistling pipes can be caused by a build up of limescale or air in the system.
Thermostat Doesn’t Work Correctly
Cause:
This could be caused by a faulty thermostat. Older thermostats tend to deteriorate over time, and can cause issues for your central heating system.
Boiler is Leaking or Dripping
Cause:
There are a number of reasons why this may happen, from loose connections inside the boiler, to broken parts.
Boiler is Losing Pressure
Cause:
If you have a pressurized system, you may notice that it keeps losing pressure. This could be caused by a water leak, or a problem with the expansion vessel.
A boiler is one of the most important appliances in the home, which is why you should keep an eye out for any of these common boiler problems.
Approximate boiler and central heating engineer prices and completion times:
| Job | Details | Price range | Typical time to comlete job |
| Power flush standard gas central heating system | Based on a three-bed semi-detached house with 10 radiators. Includes labour and all chemicals and equipment needed. | £330-£450 | 1 day |
| Carry out an annual service on a standard combi gas boiler | n/a | £53-£72 | 1–1.5 hours |
| Carry out an annual service on a living room gas fire | n/a | £50-£68 | 1–1.5 hours |
| Fit new TRVs – small two-bed house | Supply and fit new thermostatic radiator valves (TRVs) in a small two-bed terraced house with eight radiators. | £220-£330 | 4-6 hours |
| Fit new TRVs – medium three-bed house | Supply and fit new thermostatic radiator valves (TRVs) in a medium three-bed semi-detached house with 10 radiators. | £269-£400 | 5-8 hours |
| Fit new TRVs – large four-bed house | Supply and fit new thermostatic radiator valves in a large four-bed detached house with 14 radiators. | £350-£520 | 6–10 hours |
| Install a replacement fan for standard combi gas boiler | Supply and fit a replacement fan for a standard combi gas boiler. | £200-£270 | 1–2 hours |
| Install magnetic filters on a standard combi gas boiler | n/a | £158-£240 | 2–3 hours |
| Supply and fit new room thermostat | Supply and fit a new wireless room thermostat. | £125-£190 | 1–2 hours |
| Supply and fit one radiator | Remove existing radiator. Supply and fit a new radiator – 600mm x 1000mm double panel. Assuming all pipework is the correct size and in the right place. | £150-£228 | 1.5–3 hours |
| Supply and fit new boiler | Supply and fit a new boiler (Which? Best Buy Vaillant ecoTEC plus 831 or similar) with new timer and regulator. Assuming that the gas pipe is of adequate size and boiler flue in same place. | £1,600-£2,008 | 1-2 days |
| Supply and fit a new central heating pump | Trader to recommend a standard pump of a reliable brand. Assuming that replacement is like for like and no modifications are needed. | £130-£165 | 1-2 hours |
