What to do if your boiler breaks down

A boiler breakdown can be a miserable ordeal. Especially if it happens during the winter! But whilst it’s advisable to have a professional take care of most boiler repairs, not all problems need an engineer’s expertise. So before you arrange a call-out here are five common boiler issues, along with their tell-tale signs and the simple fixes you can try yourself.

Low pressure

Low pressure

  • Your boiler switches itself off
  • Your central heating makes banging sounds
  • Your upstairs radiators, or those furthest from the boiler, stop heating

Fixing this usually takes little more than a tweak of the filling loop on your boiler. So if the pressure gauge on your boiler control panel reads less than 1 bar, carefully use your valve to increase it to between 1 and 1.5. We have a handy guide to fixing boiler pressure issues here.

Just bear in mind that you might have to reset your boiler once you’ve re-pressurised the system, so check your manufacturer’s guide for details on how to do this. And if your boiler keeps losing pressure it might indicate a pipe leak in the system. An engineer will need to check this for you.

A frozen condensate pipe

A frozen condensate pipe

  • The boiler makes gurgling sounds when you try to use it
  • Your boiler won’t fire up
  • The temperature outside has been particularly cold

Cold weather can be a boiler’s worst nightmare, and a frozen condensate pipe is one of the biggest causes of winter boiler breakdowns. So try thawing it yourself by applying hot (but not boiling) water and a warm compress – like a hot water bottle – directly to the pipe. We have a detailed guide for dealing with frozen pipes here.

A problem with your boiler or thermostat settings

  • Your boiler doesn’t come on when it should, or comes on erratically
  • The boiler doesn’t fire up
  • You have an error displaying (or a blank panel) on your thermostat

 

Your timer settings may have changed if you’ve had a power cut, or someone’s accidentally knocked the panel. So double check and adjust them if you need to, using your boiler manual if you’re unsure. Check that the central heating dial on the boiler control panel is turned up too.

Next, check the thermostat settings. If the temperature is set below 21℃ your boiler might not fire up, so increase the temperature to see if this helps. If there’s nothing displayed on the thermostat panel you might need to replace the batteries.

The pilot light has gone out

The pilot light has gone out

  • There’s no visible pilot light on your boiler
  • Your boiler won’t fire up

A pilot light can blow out for a number of reasons, but you should be able to reignite it by following the instructions on your boiler. If, however, you smell gas or notice any other signs, such as a change in the flame colour or sooty marks on (or around) the boiler, don’t try to reignite it. Turn the boiler off and call the emergency gas line on 0800 111 999. And if your pilot light persistently blows out, have a Gas Safe engineer take a look at it.

The boiler locks out and needs resetting

The boiler locks out and needs resetting

  • The lock-out (red) light on your boiler keeps coming on
  • Your boiler control panel displays an error code
  • The boiler won’t fire up

Sometimes a simple reset is all that’s needed. You should find your boiler reset button somewhere on the front control panel. If you can’t locate it, take a look at your boiler manual then follow the instructions on how to reset the system. If this doesn’t work you could try switching the boiler off and then on again. And if you keep having to reset it, have it checked by an engineer. It could be a sign of a bigger problem.

Remember, it’s only safe to perform the most minor boiler repairs yourself. So, if you’re in doubt about any of the above, leave the job to a professional.


Once your boiler is up and running again, a regular check-up should keep everything in order. So have it serviced annually by a registered engineer. HomeCare, or an alternative boiler cover policy, includes a boiler service each contract year. Or you can arrange a one-off boiler repair with a reputable Gas Safe professional.  

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