7 most common boiler issues and causes


Boiler breakdown is perhaps the number one nightmare keeping us up at night when we think about what can go wrong in the home. Whilst you can’t always prevent the bad luck of a boiler breakdown, knowing some of the most common boiler issues and causes can help you know what to look out for.

Here are some common boiler problems and causes with advice on finding a solution.

1. Pilot light going out
If your pilot light has gone out this may be the result of your gas supply not being able to flow properly due to a broken or worn thermocouple. It may also be that an obstructive deposit of some kind has built up around the pilot assembly preventing the thermocouple from sensing the flame.  Check for any build-up, then also check your gas supply, as if there is work being done in your area your utility provider may have temporarily isolated the supply.

2. Dripping or leakage
This is a surefire sign of boiler breakdown. There may be a damaged pressure valve or pump seal. If the leak is coming from the seal around the pump of your heating system, it may be that it is broken or natural wear and tear has occurred and it needs to be replaced. A trained installer will be able to help you figure out the source of the leaks.

3. No heating or hot water
This can be caused by anything from faulty motorised valves, broken system diaphragms and airlocks, to low pressure or a broken thermostat. You can identify if low pressure is the culprit by checking the pressure gauge to see if it is below 1. If it is, then it may need repressurising. If your thermostat is broken there may be a possible solution in the device’s manufacturer guide.

4. Frozen condensate pipe
A condensate pipe is responsible for transporting the condensate from your boiler to your outside drain. In colder weather, the condensate can freeze and cause a blockage. Left unchecked, this issue can cause the condensate to revert back up into the boiler potentially resulting in a breakdown. Luckily this is a problem that can be fixed quickly and easily by defrosting the pipe.

5. Whistling and gurgling noises
You usually listen out for noises that tell you the boiler has been switched on, but be aware of when those noises sound strange. Unusual boiler noise can be caused by air in the system, a faulty pump, low water pressure or even a build-up of limescale known as “kettling.”

6. Boiler not responding to thermostat
If your boiler is completely failing to respond to your thermostat, the controls may be broken or old. Try replacing the batteries or position the device closer to the boiler and check for any interference that could be causing an issue. If the problem with your thermostat persists, take a look at the instructions booklet for advice or contact the manufacturer for help.

7. Boiler turning on and off
If your boiler keeps turning on and off, the pressure could be low or there could be a blockage that is inhibiting the system. Check your system’s pressure gauge and repressurise the boiler if it is set below 1. Alternatively, contact a Gas Safe registered engineer.

Each of these common boiler problems highlights the importance of boiler service maintenance. One of the many reasons consistent maintenance of your boiler is essential is because it can help to stop the above issues in their tracks and save you both money and peace of mind.

Plumr pride themselves on offering expert plumbing solutions across South London. If you’re having boiler problems or would like your boiler serviced and the system checked please contact our team today.


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