Jammed thermostatic radiator valve - how to free?

[zebedee]

I have some fairly old Honeywell thermostatic radiator valves. Some of them won't free up unless I hold a rope burner (basically a 1000 degree c cigarette lighter) onto the pipe to get the stone cold water under them (even though other rads are already by thennice and hot) and they they crack open with a loud crack. One in particular however oddly always has a very hot supply pipe but won't open anyway, or if it is it is only a tiny amount as the area next to the valve is warm but not the rest of the rad. That could just be conducting along the metal of the supply pipe, valve and radiator though. I have tried wiggling the control from off to full many many times in quick succession, trying to pull and push on it and all to no avail. Is there anything else I can do other than replace it (probably with a manual one to be honest!)

cheers

[netherfield]

Ferg could be along soon.

[Ledaig]

There's probably crap jamming the valve within the body - the following worked for one of mine........ If you remove the actual cap, you should see a plunger which controls the flow (its position in turn is controled by the cap you have removed). If you push this plunger up and down a few times with the system turned on so you have some flow, you may well dislodge the crud.

[Vee]

zebedee said:

One in particular however oddly always has a very hot supply pipe but won't open anyway, or if it is it is only a tiny amount as the area next to the valve is warm but not the rest of the rad. That could just be conducting along the metal of the supply pipe, valve and radiator though. I have tried wiggling the control from off to full many many times in quick succession, trying to pull and push on it and all to no avail. Is there anything else I can do other than replace it (probably with a manual one to be honest!)

cheers

Yes, check that the lockshield valve at the other end of the rad is open. If it isn't then there will not be any hot flowing through.

Edited by Vee on Tuesday 19th October 16:49

[Mister c]

Club hammer.....bang lightly on top of the valve with the plastic knob removed.
Works every time for me.
If it is thermostatic, remove the thermostat bit , push the pin in a few times and that sorts it normally, or revert to plan a, ie bang it a little on the valve body.
Normally happens the first time you turn it on in the winter.

[Ferg]

My personal version is to remove the head and push down very hard a few times to flex the rubber washer in the valve until it breaks off the seating. Pulling the pin rarely works as they are only bearing on the jumper.