Boiler Repair

Common Boiler Problems

We rely on our boilers for heating our homes and providing a constant supply of hot water, so we certainly notice if the boiler’s not working as it should do. In today’s modern world, hot water is indispensable for a smooth running household.

To ensure that your boiler is functioning correctly it’s recommended that you get it serviced annually. However, there may be occasions between an engineer’s visit when problems occur. Here’s a troubleshooting guide to the most common boiler problems.

Boiler RepairIrregular Heat

If your radiators are cold at the top but hot at the bottom it usually means there’s an air block or rust build-up in the pipes. You can try and bleed the radiators yourself to fix the problem by releasing the trapped air. To bleed the radiators, turn off the heating and wait for it to cool down. Insert a radiator key into the valve. A hissing sound means the air is escaping. When water starts to drip out, close the valve. If this hasn’t fixed the problem you may need a power flush performed by a qualified engineer.

No Hot Water

There’s nothing worse than a cold shower! It could be a down to a broken airlock, a faulty valve or low water level.

Pilot Light Goes Out

This could be due to a deposit build-up in the pilot light mechanism or a broken thermocouple which will prevent the gas supply from reaching the pilot light.

Boiler Switches Off

If your boiler is constantly switching itself off it may have an air block or faulty pump. Also check for low water pressure and ensure the thermostat is working properly. You may need to invest in a new thermostat. Ask your boiler repair engineer for more efficient thermostat options.


Banging, gurgling, whistling: these are all noises that could indicate an air block, pump failure or kettling. Kettling is caused by limescale build-up, in which case your boiler will need power flushing.


Water dripping from your boiler can be caused by a loose connection or broken parts. This can cause the water pressure to drop. However, dripping water can also be a sign that the water pressure’s too high. Your pressure gauge should always be set between 1 and 1.5 bars. If the leaking persists you’ll need to call in professional help.


KMHGas provides a prompt, reliable and professional service in all aspects of boiler repairs. Whatever your boiler concerns, call us today for helpful information and advice.