Boiler not working?

No heating or hot water

The boiler is dead or not firing at all. Start with the simple things.

Try these first

1. 1Is there power? Check the boiler display, the fused spur next to it and your fuse box.
2. 2Look at the pressure gauge. Below about 1 bar on a combi or system boiler and it may refuse to fire.
3. 3Check the timer and thermostat. A power cut can reset them, and a thermostat set below room temperature will not call for heat.
4. 4On an oil boiler, check the tank has oil in it. On LPG, check the tank or bottles.
5. 5In a freeze, a fault plus a gurgling noise usually means a frozen condensate pipe outside.
6. 6Press reset once. If it locks out again, leave it.

Never open the boiler’s case or touch the gas supply. Smell gas? Ring 0800 111 999.

Hot water but no heating

The boiler is working, so the problem is usually in the controls or the system.

Try these first

1. 1Turn the thermostat up a few degrees above the room temperature and wait a few minutes.
2. 2Check the timer or programmer is set to heating on, not hot water only.
3. 3Replace the batteries in a wireless thermostat.
4. 4Check the radiator valves are open.

Never open the boiler’s case or touch the gas supply. Smell gas? Ring 0800 111 999.

Pressure is low or keeps dropping

You can usually top it back up yourself in a few minutes.

Try these first

1. 1With the heating off and the system cold, the gauge should read about 1 to 1.5 bar.
2. 2Top it up using the filling loop under the boiler, slowly, then close both valves.
3. 3Reset the boiler.
4. 4Look for drips at radiator valves and a dripping copper pipe outside, which is the pressure relief valve.

Never open the boiler’s case or touch the gas supply. Smell gas? Ring 0800 111 999.

It’s showing a fault code

The code tells you what the boiler has detected, not always why.

Try these first

1. 1Note the code exactly, including any letters, and the boiler make and model on the front.
2. 2Look it up in the manual or on the manufacturer’s website.
3. 3Codes for low pressure or ignition lockout are often something you can fix: see the pressure and frozen pipe checks.
4. 4Press reset once.

Never open the boiler’s case or touch the gas supply. Smell gas? Ring 0800 111 999.

It stopped in the freeze

Almost always the condensate pipe outside. You can usually thaw it yourself.

Try these first

1. 1Find the white or grey plastic pipe that leaves the boiler and runs outside to a drain.
2. 2Pour warm water, not boiling, slowly along the outside section, especially bends and the open end.
3. 3Or hold a hot water bottle against it.
4. 4Reset the boiler once the ice has cleared.

Never open the boiler’s case or touch the gas supply. Smell gas? Ring 0800 111 999.

It’s leaking or dripping

Contain it, then work out where it is coming from.

Try these first

1. 1Put a bowl or towel under it and keep electrics dry.
2. 2If water is coming from inside the boiler case, switch the boiler off at the spur.
3. 3A drip outside from a copper pipe is the pressure relief valve: note it and check the pressure gauge.
4. 4A slow weep at a radiator valve can sometimes be stopped by gently tightening the nut a quarter turn.

Never open the boiler’s case or touch the gas supply. Smell gas? Ring 0800 111 999.

It’s banging or noisy

In West Norfolk’s hard water, the usual cause is limescale or sludge.

Try these first

1. 1Kettling, a rumble like a kettle boiling, usually means limescale or sludge in the heat exchanger.
2. 2Gurgling can be air in the system: bleed the radiators, then check the pressure.
3. 3Banging when the hot tap shuts off is often the pipes, not the boiler.

Never open the boiler’s case or touch the gas supply. Smell gas? Ring 0800 111 999.