Troubleshooting: When You Have A Cold Radiator

Step 1: All the radiators are cool or lukewarm

It might sound obvious but first check that you have turned your heating on. If everything's on but all of your radiators are still cold at the top, your heating system could be full of a sludge. Give the professionals a call to come round and desludge the system for you.

Step 2: One radiator stays cool

If all your radiators except one are working, there are a couple of things you can do to get the cold one playing ball. First check both valves on the the sides of the radiator are open, and if a thermostatic valve is fitted, remove the top and check the operating pin moves freely.

Then try turning off all other radiators and seeing if that one gets hot. If it does - turn the other radiators on one by one. If it still won't work then the valve might be damaged. "How to replace a damaged radiator valve" will show you how to swap it.

Step 3: Cold bottom section of radiator

This problem tends to be caused by sludge in the radiator. Take the radiator off, get it outside and hose it through. Watch "How to temporarily remove a radiator for decorating" to see how.

Step 4: Top section of the radiator is cold

If the bottom of your radiator is heating up but not the top half, it's most likely that air is trapped in the system. It's simple enough to sort this out yourself by bleeding the radiators. Our film "How to bleed a radiator" will show you how.

Step 5: Upstairs radiators are cold

If you live in a house with a conventional heating system you'll need to go into the loft to check out your header tank. Refil the tank so that there is just enough water to make the ball float. Don't fill it up completely, you don't want the tank to overflow! Now the upstairs radiators should start heating but will also need bleeding.

Step 6: Downstairs radiators are cold

This is definitly a job for us Homeserve experts. Give us a call and we'll soon get your home toasty warm again. Job done.