Central Heating Not Working London — Causes, Signs & Fixes

Boiler fault or lockout

The boiler has locked out due to a fault code. Check the display for an error code — note it down and call us. Most lockouts are resolved within the first visit.

Programmer or thermostat not calling for heat

Check your programmer is set to 'heating on' and your room thermostat is set above the current room temperature. TRVs on all radiators stuck closed is another overlooked cause.

Motorised zone valve failure

On a Y-plan or S-plan system, the heating zone valve opens to allow flow to radiators. A failed valve or motor means the heating circuit gets no hot water.

Pump failure

If the pump fails, the boiler fires but heat cannot circulate. The boiler overheats and cuts out shortly after starting.

No gas supply

Check other gas appliances (hob, oven). If nothing works, call your gas supplier. If other appliances work, the problem is the boiler's gas valve or ignition system.

Frozen condensate pipe

In cold weather, the white plastic condensate pipe (runs outside) freezes and causes the boiler to lock out. Defrost with warm water.

My heating stopped working overnight — what should I check first?

1) Is the programmer set correctly? 2) Is the room thermostat set above room temperature? 3) Is the boiler pressure above 1 bar? 4) Is there a fault code on the boiler display? If all check out and still no heat, call us.

How quickly can you restore central heating?

RARE targets 2-hour response for heating emergencies. Most faults are resolved on the same visit. We stock common replacement parts for Vaillant, Worcester Bosch, Viessmann and ATAG.

Will my boiler need replacing if the heating is not working?

Most heating failures are component faults rather than end-of-life boiler failures. We will always advise repair vs replacement honestly based on the boiler's age, condition and repair cost.

What is a 'zone valve' and how do I know if mine has failed?

A zone valve is an electrically operated valve that opens to allow hot water to flow to your radiators or cylinder. If it fails open, heating runs continuously. If it fails closed, the heating zone gets no heat. Our engineer tests it with a multimeter and wiring check.