Central heating: one radiator stays stone-cold but pipe feeding it is really hot. WTH :( <New thermo

KatanaDV20 · 3 Oct 2012 at 23:40

OcUk GD - can any central-heating nerds help

I've just had a new thermostat fitted to the boiler. The controller is a wireless affair fixed to the wall in the living room. It works brilliantly.

I dont think the new thermo has ANYTHING to do with my problem but I thought Id mention it.

When I tested the new thermo all the radiators in the house blasted out heat. Except one in the kitchen.

This radiator stays stone cold - but the pipe leading INTO it is really hot. What should I do?

Thanks for any ideas

KatanaDV20 · 3 Oct 2012 at 23:49

Ahh sorry I forgot to mention an important point: the dial mounted on the pipe is turned to #6 (max setting). Radiator still stays cold.

Edit: bleeding! Hmm that maybe it. Bummer.... I dont have the special key thingy to turn the bleeders.

KatanaDV20 · 4 Oct 2012 at 00:37

aln said:
A flat head screwdriver should do the trick. Best done when the radiators are turned off, you'll probably need to let some more water into the system when you're done. Consult your manual for boiler pressure, yadda, yadda, yadda.

Thanks , i will try that. So kill the boiler (turn of heating) wait a bit and then do the bleed?

KatanaDV20 · 5 Oct 2012 at 21:54

Skii said:
Sounds like a similar issue to what we have every year You need to take the Thermostatic valve off the end of the radiator - usually they just twist off (you have to hold the end of the assembly and twist the collar that holds it on to the pipe)

This will reveal a small pin that should be spring loaded, if you are in a hard water area like me these seize up after not being used for 6 months so a gentle tap or two with the end of a hammer or screwdriver should get it moving again.

Replace the plastic valve assembly and you should be good to go

I did this completely by accident - and you are right it worked brilliantly

About 2 hrs ago I was getting annoyed and twisted the valve kinda hard because I was ____d-off with it..and it came away in my hand (just like in the diagram you posted). I was in a panic for a few seconds but when no geyeser of water appeared I calmed down. Thats when I noticed that pin. I gave it a whack with a shoe and in under 10 secs the radiator was/is burning hot!! Thanks for replying!! :cool: