Thermostatic Radiator Valves

[alan13]

Hi everyone-@Happy New Year, if its not too late for that..!!..Its my first try at posting a question, so fingers crossed..
Moved to a house with TRV's fitted, 'Myson TRV 2 WAY' is on their tops. Do they wear out?..or break? My problem is several of the radiators will only heat up if I unscrew the top part of the valve from the bottom part, and then the rad.is full on.There is a 'plunging' bit that moves down out of the top part to connect with the pin in the lower part, and as you turn the control mechanism top around the lower part on the top housing, this can be seen to work. The pins poking up out of the part of the valve plumbed in to the radiators seem very stiff and so I have tried to loosen these a little, forcing them a few times in case the pins have just got stuck, and everything else I can think of (including WD40 !!)..but then put the valve back together, and it still just turns the radiator off.
I am kind-of angry with myself as I have not yet cracked this, as (usually..) I'm pretty good at stuff like this..
..Help, anyone, please..

 

[D_Hailsham]

The pins poking up out of the part of the valve plumbed in to the radiators seem very stiff and so I have tried to loosen these a little, forcing them a few times

The pin should move down easily, with a bit of pressure and then spring back up. If they do not do this, try hitting the side of the valve with a hammer - but not too hard. If that does not loosen them you may need to use a pair of pliers move the pin up and down - but take care not to bend the pin. The valve will not work properly if the pin is stiff.

If no joy, you will have to replace the complete TRV - Drayton TRV4 are very good.

When replacing the head, make sure that it is set to the highest setting; this makes it easier to do up the knurled nut.

PS the valve may be sticking because there is a lot of crud in the system - it may need flushing.