I’ve got a problem with one cold radiator downstairs in our house. I’ve done the usual checks; TRV pin, lockshield valve fully open, bleed etc. the incoming pipe and valve feels warm up to the point in enters the rad. the pipe and valve the other end aren’t! Any ideas?? Thanks.

Tap the pin on the valve that the TRV pushes against lightly with a hammer. Sometimes they get stuck :(. I have to do that every year in our office as winter comes (apologies if you have already done that)

TRVs can get stuck even if the pin is free – I had to replace one for exactly that reason recently.

Thanks for the replies. Yeah, the pin moves in and out freely so it might be a complete valve replacement job.

The pin might pull out freely but that doesn’t mean that it is free internally. You shouldn’t have to pull the pin out, it should just pop out. If it doesn’t then tap it with a hammer

Has it always been like that or has it just started?

Found on one of our rads that even with the lockshield open we had to tighten lockshields on other rads in the house to get any heat in the rad. Might try half closing all of them, seeing what’s hot and what’s not, then opening the ones that are still cold. Took a bit of fiddling to get ours all balanced.

Though most likely hitting the pin with a hammer will sort it 🙂

I had similar – BG wanted to charge me £££ for a power flush…nah

Solved it eventually by balancing the flow on all the radiators on the loop using the lockshield valve to throttle the temp drop between the inlet pipe and the outlet pipe to 10 degrees
bought a cheap IR thermometer from Maplin to take the measurements incase your wondering

will be worth trying the above if all else fails (personally I’d try the above before replacing valves)

Is air actually coming out ok when you try to bleed it? If not take the bleed valve out and stick a thin wire through the hole (quite often gets blocked thus you can’t bleed)

Is air actually coming out ok when you try to bleed it? If not take the bleed valve out and stick a thin wire through the hole (quite often gets blocked thus you can’t bleed)

Air lock, shut off all the thermostats in the rest of the house apart from the cold one for a few minutes. it will soon get hot again.