10 Common Boiler Problems and How to Fix Them (Before Calling a Plumber)

1. No Heat or Hot Water

This is often caused by broken diaphragms, airlocks, or thermostat issues. Start by checking your thermostat settings and boiler pressure. If that doesn’t help, it might be time to call a professional.

2. Leaking and Dripping

Leaks usually result from broken components like internal seals or the pressure valve. If you see water around your boiler, shut it down and contact a Gas Safe registered engineer.

3. Strange Banging or Whistling Noises

These sounds are typically caused by kettling, which happens due to limescale buildup or trapped air in the system. Flushing the system or bleeding your radiators often resolves it.

4. Low Boiler Pressure

If the pressure gauge reads below 1, your boiler won’t work efficiently. You can repressurize it using the filling loop, but follow your boiler manual carefully.

5. Frozen Condensate Pipe

During colder months, this pipe can freeze, causing your boiler to shut down. Pour warm (not boiling) water over it to thaw and restore function.

6. Radiators Not Heating Up

Trapped air prevents radiators from heating evenly. Bleeding your radiators should help restore proper heating.

7. Pilot Light Keeps Going Out

A faulty thermocouple or a draught could be the cause. Make sure nothing is disrupting the gas flow and have the thermocouple checked if the issue continues.

8. Boiler Keeps Switching Off

Low water pressure or a faulty thermostat may cause frequent shutdowns. Reset the system and inspect the water levels and temperature controls.

9. Thermostat Problems

Outdated or broken thermostats lead to incorrect temperature readings. Consider upgrading to a smart thermostat for better energy efficiency and accuracy.

10. Unresponsive Controls

If your boiler isn’t responding, check the batteries in the controls, power supply, and fuse box. Sometimes a simple system reset can fix it.