5 common boiler problems – and simple fixes to solve them

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. Here’s how to tackle five of the most common boiler issues, so you can keep your home warm and cosy.

1. Low pressure


  • Boiler switches itself off
  • Central heating makes banging sounds
  • Radiators furthest from the boiler stop heating up


Tweaking the filling loop on your boiler should take care of this. 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.

You might need 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.

Low pressure on your home boiler.

2. Frozen condensate pipe


  • Gurgling sounds from the boiler when you try to use it
  • Boiler won’t fire up
  • Outside temperature is particularly low


Cold weather can be a boiler’s worst nightmare, and a frozen condensate pipe is one of the biggest causes of winter boiler breakdowns. 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.

Frozen pipes.

3. Boiler or thermostat settings issues


  • Boiler doesn’t come on when it should, or comes on erratically
  • Boiler doesn’t fire up
  • Error message (or a blank panel) displaying on your thermostat


Your timer settings may have changed if you’ve had a power cut, or someone’s accidentally knocked the panel. 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.

Set your thermostat to 21℃.

4. The pilot light has gone out


  • No visible pilot light on your boiler
  • Boiler won’t fire up


A pilot light can blow out for several 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.

Your boiler won’t fire up.

5. Boiler locks out and needs resetting


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


Sometimes a simple reset is all that’s needed - the boiler reset button should be somewhere on the front control panel. If you can’t find it, check your boiler manual and 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.

A simple reset may help your boiler.

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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