What can go wrong with a boiler?

Boiler and hot water are the main heating systems in most homes. However, boilers are prone to malfunction, especially when they have not been in use for some time. Here is a list of some of the most common boiler problems and their solutions.

Ten common problems with boilers

Our central heating system is like hygiene – as long as it is okay we don’t notice it, but the minute there is a problem it becomes a real issue. No matter how well ordered our lives, a broken boiler and the accompanying lack of heating and hot water can plunge us into chaos, and quite often, misery.

A winter of misery

While a broken boiler in the summer can be a real inconvenience, the majority of boiler breakdowns will occur at the start of the winter. For a few months the boilers have been inactive, and then when the weather turns colder, they are forced back into life and this is when expensive and inconvenient problems can arise. And of course, that is the time when everyone is experiencing problems so it could be a few days before a technician can even get to see you.

Some common boiler problems can be solved without the need to call in a heating technician, while others will require the services of a qualified and experienced professional. If in doubt, it’s always best to seek professional help from a reputable HVAC technician. At least, using our guide, you will be able to identify many of the issues and then decide upon the best, and least expensive, course of action.

Here are the 10 most common problems you are likely to encounter:

  1. No heat or hot water – potential causes include too much air in the system and airlocks, failure of motorized valves, issues with the thermostat or low water levels.
  2. Leaking and dripping – a variety of issues could cause your boiler to leak water. It will depend on where the water is leaking from to determine the cause.
  3. Strange banging, whistling or gurgling noises – air in the system is a common cause, alternatively it could be that the water pressure is too low or it’s kettling.
  4. Pilot light goes out – could be a broken thermocouple which is removing the gas supply to the pilot light, a draft blowing the pilot light out or a deposit built up in the pilot light.
  5. Losing pressure – a water leak in the system is the most common reason for a loss of pressure. But it could also mean that the pressure relief valve needs replacing.
  6. Frozen condensate pipe – Thawing a frozen condensate pipe should ideally be done by a qualified technician.
  7. Thermostat issues – if the thermostat is losing accuracy or turning the heating on/off when its not supposed to it might be time to invest in a newer, more energy efficient one.
  8. Kettling – hearing a strange rumbling noise? When lime scale builds up on your boiler’s heat exchange the water flow is restricted. This water starts to heat and steam and the noise you get is referred to as kettling.
  9. Radiators not getting hot – corroded pipework can cause sludge to gather in the system, preventing the free flow of hot water to the radiators. Chemically cleaning or flushing the system will remove these deposits.
  10. Boiler keeps switching itself off – could be low water pressure, a problem with the thermostat or a lack of water flow due to a closed valve, air or the pump not circulating the water in the system properly.

Further reading:

What Can Cause a Furnace to Stop Working?

Should you repair or replace your furnace?

What is a heat pump and how does it work?

Is converting from oil to gas worth it?