Boiler works but radiators stay cold

If your boiler works but the radiators are not heating up, the likely cause could be a faulty boiler pump or your central heating controls.

If your boiler works but the radiators are not heating up, then the likely cause is a faulty boiler pump or your central heating controls.

If your boiler works but the radiators are cold, check that the thermostat or timer is working correctly. If they need replacing you'll need a registered heating professional to carry out the work.

The thermostat or timer is faulty

Double check that the thermostat or timer is working correctly. If you find a fault, contact your local heating engineer to arrange for a replacement to be installed.

There are air pockets in the system

You may have air in your system if your radiators are staying cold. You can tell when this is happening because your radiators will go cold alternately as the air pockets move around the heating system. See our article on how to bleed a radiator first, before getting in professional help.

Blockages and debris within system

Your heating may also be contaminated with debris or sludge, this can inhibit circulation and cause radiators to not heat up correctly. If you're not confident that you'll be able to resolve this, it might be time to call in a Gas Safe Registered Engineer.

The pump is faulty

If you have tried all of the above and our guide to diagnosing central heating problems hasn't helped, it might be that your circulation pump is faulty. If this is the case, you'll need to call a registered heating professional to repair or replace it.

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