How to troubleshoot a cold radiator

Watch this video tutorial on how to troubleshoot a cold radiator.

Step 1:
Check that you have turned your heating on. If it's on and your radiators are still cold, your heating system could be full of a sludge stopping the circulation of hot water. To sort it out, your heating system needs to be thoroughly cleaned with heating sludge remover. Add some of this according to the manufacturer's instructions into the feed and expansion cistern, and then a few days later, the system will need to be emptied and refilled. If you haven't cleared out a heating system before it might be worth getting the professionals in.

Step 2:
If all your radiators except one are working, check that both valves on the sides of the radiator are open. If this doesn't work, the valves may be blocked because of limescale. If this is the case, the radiator may need to be flushed out.

Step 3:
This problem can also be caused by sludge in the system. Again, add some sludge remover and give the whole system a refill.

Step 4:
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.

Step 5:
So the upstairs is cold as none of the radiators are working. This usually means that the feed and expansion cistern is empty. The cistern is usually found in the loft. Refill the cistern so that there is just enough water to make the ball float. Don't fill it up completely as there must be enough room for the water to expand. You don't want the cistern to overflow! With a full cistern, the upstairs radiators should start heating but it is a good idea to get a professional plumber in to work out why the cistern ran dry in the first place.

Step 6:
If it's chilly in the lounge and the rest of the downstairs, then it is a sign that your pump is broken or at least on its way out. Not a nice prospect and you definitely need a professional to help you sort it out.