Thermostatic rad valve

G20

On one of my upstairs rads, the thermostat is obviously jammed since the rad continues to pump out heat no matter how low I set the thermostat.
My main question is, if I bought a new TRV would I be able to fit it myself or would I be in danger of flooding the place?

My secondary question is, would it be possible for me to remove the plastic cover to get a look at the needle and see if it is jammed? There is no end screw that I could simply unscrew to take off the cover.

Pete67

You need to drain the system below the level of the radiator to change the TRV, however there is a good chance that the valve is fine, and the thermostatic head has failed. You can replace the head without draining, it is usually held in place from below by a large diameter threaded collar. With the head removed the valve should be fully open, you can close it by gently pushing the pin downwards about 5 or 6 mm. It should spring back up immediately.

G20

Thanks, Pete67,
Yes, it has that large diametre collar you mentioned.
I think I'm going to find your advice helpful.

Cheers.

kay 9

Try pushing the pin first mate, they can get stuck over time and are usually easy enough to free up. If not then it's no big job to change the rad valve. And if required its no more than a 30 min job for a plumber.

aujopimur

Drain,replace valve, refill 30mins you must be joking.

kay 9

Ah my bad, forgot the valve had to be changed possibly:D Need my sleep:rolleyes:
Excuse my hast.:) Thought it was changing rad, crossed my wires mate.

DublinDilbert

First you need to figure out which bit is faulty. It could even be that the two halves of the valve aren't assembled correctly.

The "TRV" can be spit into its two halves. One half controls the water the other half is the adjustment/stat part. They are joined together by an M30 thread/nut.

If you put the TRV to the coolest setting / off, you should be able to unscrew the M30 nut that holds the two halves together. Then you'll be able to check the valve half that controls the water.

If you get it into its two halves poeple here will be able to advise on how to test the valve.

The top half might just be faulty and need to be replaced with a similar one. If your any way handy you should be able to sort this out...

Jediknight

Remove head, should only be on hand tight. If pin is stuck in extended position try forcing it down with pliers etc, if trv head is seazed open replace head with simalier size and threads.
If entire valve needs replaced ...do not waste time draining system, go up into the loft, plug vent pipe hanging over F&E tank, plug feed connection out of F&E tank, go back down to radiator and close opposite lockshield valve. Open vent screw into a cloth or basin untill pressure eases off, close vent screw then easily remove problem TRV while entire system water is held safely in a vacum.. once trv is replaced, go back into loft and remove vent and cold-feed plugs, open up lockshield valve of radiator and bleed off any air that has entered rad, check valve for leaks.......approx time of repair = 10 minutes !