Central Heating

[IBAR]

I seem to have a problem with a single radiator not working upstairs.  There are only 2 rads upstairs, of which one works and the other is completely cold (it used to work a few weeks ago..).  I have bled all the radiators, with particular attention to the one that preceeds it in the circuit, and it is still cold.

Any ideas how to fix it? could there be an air lock on the pipe?

[woofgang]

might be that the valve is stuck shut or there is sediment in the pipe. To sort out sediment,try draining out that radiator from the bottom with the system hot. If a load of gronk comes out with the water, drain out your system, stck in some fernox or equivalent, run hot for a few days then drain and repeat.

[sddsddean]

Have you get thermostat valves on the rads? They usually look like upside down plastic cups with a load of slots in them and a number ring at the bottom. If so, the pin could be stuck. (This happens to at least one of my rads every year). Look at the base of the plastic fitting above the metal pipe it is sitting on, and you will see a knurled collar. Unscrew this and lift the valve off. You will now see a little pin in the middle of the brass fitting. Tap this very gently with a hammer. You might see it spring up. Screw the valve back on and hopefully the rad now works

[richfo]

I agree with the previous two postings, especially about the gunk in the system or a sticky valve. One other thing to try is to turn off all of the other rads by the valves leaving just that one on. If it is a small blockage or air block it may move then.

[Octavius]

Make sure both valves are fully open