REPLACING A VERY OLD TRV

lohr500

As @molerat states, it is important to make sure the pin in the metal part of the valve assembly is moving freely. 

I thought a couple of our TRV heads had failed, but it was actually a problem with the valve pins sticking on both radiators.

I was able to coax both valves back into life by carefully rotating the pins with the end of a pair of pliers to free them off and then push them in and out a dozen or so times to free them off..

Once free, the pins should travel outwards on their own as they are spring loaded and it should be possible to push them inwards with a light amount of force. 

I sprayed each pin with a little GT85 lubricant and they have worked fine now for the past two or three years. The old heads also worked OK. I presume the head must have some spring loaded overload protection built in so that if the valve jams open, it doesn't damage the head mechanism. That being said, once you have checked the pins and they move freely, then probably best to replace the heads anyway. They look quite old. 

sandramcl

Thank you to all who responded.  I will check Amazon and the Danfoss website.

sandramcl

Last question I think.  I would like to replace the really old Danfoss TRV head with the newer Screw on type. Is there an adaptor I can use to do this.  I saw this on Amazon but don't know if it would be suitable

molerat

IMHO that just adds another complication / moving part (and cost) into the system, just get a replacement correct head.

lohr500

molerat said:

IMHO that just adds another complication / moving part (and cost) into the system, just get a replacement correct head.

Agree. It's over complicating the set up if direct replacements are available. 

Lorian

Three votes for not doing that

sandramcl

Thank you.  I really appreciate everyone's input.