One radiator not working

[rubble2]

Hi, I know that there are a lot of threads about this type of problem, I have read them and tried most of the things suggested.

My problem is that I have one upstairs radiator that remains stone cold. I have removed the trv actuator and sure enough the pin was stuck in, I freed this off and then switched all the other radiators in the system off to try and force some flow through the problem one - no luck.

I then got brave (stupid) and unscrewed slightly the trv valve (the hex fitting with the pin passing through the centre) expecting to see water start to leak out, no water, fully unscrewed the valve but still no water???

If I try bleeding the radiator, I do not get any air out but water starts to flow straight away. Am I missing something simple? any assistance gratefully received.

Thanks

 

[nickso]

im assuming you have a danfoss rad valve. most other valves would have flooded your house when you took it apart. please say if thats wrong.

when you freed the pin did you check that it has a sprung resistance behind it. sometimes on danfoss valves you can free the pin but not the valve. if the pin moves easily but stays in and doesnt spring back out the valve is still stuck. best way to free it is to gently tap the pin until it moves the valve.

the other option is you may have a blocked pipe leading to the rad....whats yous water quality like?

 

[rubble2]

Thanks for the reply,

It is a Danfoss valve as you say, having read your advice I have checked the valve again, and it does not spring back when the pin is pushed in.
I took the valve off again, and all there is is the pin held in place with what look like a spring clip, I think that the pin has become detached from the valve seat and that the valve is still jammed shut, is that a possibility?

 

[nickso]

the pin and valve are two seperate pieces.

sounds like the valve is stuck on its seat. take the pin out of the brass nut its in and clean any debris from the pin and inside the brass nut.

put it all back together and use the flat end of the trv head to hit the pin quite sharply. it should free it but dont be too heavy when hitting it. using a hammer is sometimes too much and it breaks things hence the use of the trv head.

alternatively when the valve is dismantled stick a smallish screwdriver into the hole where the pin and nut go and wiggle it about...this should also free it but you may get varying amounts of water out of the hole.

do all of this with the pump off of course

 

[rubble2]

Thanks Nickso,

All sorted now - couldn't have done it without you