One cold radiator

[Mark Allan]

All of a sudden one of my radiators (downstairs) has stopped working. Both pipes are totally cold when system is on but all other radiators work ok. Have tried bleeding but no air came out. Does anyone have any suggestions other than calling out a plumber?

 

[Rob]

Make sure it hasnt been turned off. Then turn all the working rads off. Should force air lock to clear.

 

[Mark Allan]

thanks for this. It's definitely turned on but I'll try your suggestion. If this doesn't work do you think it will be worth looking at the pin in the trv...seen this mentioned on the site but not too sure what to do !

 

[Slugbabydotcom]

1 Try what rob says

2 Could be the TRV pin. Take the TRV head off and slap the valve about a bit. Tap it gently with a small hammer or something to free the stuck inner valve. Sometimes you can grab the pin with some pliers but take care.

3 Perhaps it's the beginning of the end for your pump

4 Could be sludge or other blockage

 

[chrishutt]

Most likely the TRV sticking shut, especially if it's an old Danfoss one. See the FAQ topic or the Wiki for advice on how to free it. Do not pull the pin out.

 

[Softus]

Sometimes you can grab the pin with some pliers but take care.

Very VERY bad advice - never pull on the pin. If it won't move upwards without pulling it then the valve has had it.

 

[Slugbabydotcom]

Depends on the make of valve and thats why I said to take care. Every year I get work in a dentist surgery where there are danfoss RAVL TRVs fitted. With these I take the pin out completely, slap the valve about a bit grease the pin with silicone and put it in the other way round. If only they would set their TRVs to max during the summer then they would not stick at all.

 

[philgee]

What sort of pipework do you have? If it's microbore, could well be sludge in them.

One way to check (if you're feeling brave), is to turn the TRV off and very slightly and carefully loosen the nut between the TRV & the pipe leading to it (assuming the flow direction goes from the TRV into the rad, not the other way round). If you get quite a lot of water then the TRV is stuck. If not, then the blockage is most likely.