What do you do when one radiator is cold?

There’s a few possibilities as to why your radiator isn’t heating up. Firstly, it’s important to ascertain whether it’s just one radiator that is the problem or whether all of them are cold.

If they are all cold you will need to confirm that the boiler is working correctly.

If it is just the one rad that’s not working then firstly make sure the valve is open. Most modern radiators have thermostatic valves fitted which display a 0 - 5 reading, 0 being off completely and 5 being fully open at at its hottest.

Thermostatic valve open and still no heat?

It could be that the thermostatic valve’s pin has got stuck in the closed position. You will need to remove the thermostat and check to see if the pin will move up and down. If it is stuck in the closed position a gentle tap on the pin a few times should free it back up.

Still nothing happening?

Have you bled the radiator?

View our tutorial here to learn how to do this.

If it’s not a thermostatic valve issue and you’ve bled the radiator, its time to call in the cavalry!

It may be that the valves are blocked. Magnetite is black sludgy stuff that builds up inside radiators. A system Powerflush will soon help get rid of this issue and restore your central heating system back to full efficiency.

These issues are all relatively easy to sort out and shouldn’t be too costly but always ensure that you use a Gas Safe Registered plumber to carry out any works on your central heating system.