one radiator doesn't work

[Steve Joyce]

Al radiators except one work - why

[Lindy Loo]

If you mean all get hot except one, then it may be full of air. Try 'venting' the rad, if it is air it will 'hiss'. When water emerges it is air free. Keep a cloth handy and just slacken the valve or you'll get flooded!! Having said that I assume the radiator is on!! Done the same myself...it don't get hot, what silly ********turned this off? Oops 'twas me!!

[daddyg]

if you have a pressurised system remember to check the pressure after you have bled the radiator or you may find more of them get cooler. There is a top up valve on the tank if you do need to repressurise it. Just make sure the pressure is in the green on the gauge. Also check that the radiator valves are open at both sides not just the one that sets the temperature.

[sddsddean]

If you have thermostat valves on your rads, check the pin (this happens to mine every summer). Look at the thermostat valve (the usually white slotted thing on one end of the rad). At the bottom of the valve there is a knurled collar above the actual water pipe. Unscrew this and lift off the thermostat. You will now see a brass fitting with a little pin in the middle. Tap the pin with a hammer VERY gently. It should pop up. If it does, screw the thermostat back on. Job done.

[ianess]

Had this problem once on a twin-entry radiator [where the entry and exit pipes were both on the same side] and found that there is a tube inside to take the hot water to the far end. The tube had become detached resulting in the hot water being sucked out as soon as it reached the radiator so it would never get hot. Hope all that made some sort of sense. In my case I replaced the entire radiator and the problem was solved. Good luck.