Thermostatic rad valve won't turn off/down

[patagonia]

We have Lifestyle thermo rad valves which keep sticking. A couple won't turn off or down so sometimes the rooms get too hot and we are wasting money on gas. What setting should the head be at when one takes it off? If the pin doesn't move with pressure and has to be hit, should that be sideways or on top? Does it matter which end of the rad the thermo valve is fixed to? Ours are on the flow.

Thanks in advance.

 

[motx]

When turning system on touch the pipes and which side get hot first is the side to be fitted.
Regarding the system if it keeps of sticking may be clean hole system due to slugg build up. Heating should be constant and not over heating if have controled valves.

 

[D_Hailsham]

1. Set the TRV to max when removing and replacing.

2. Never hit the pin. You can try tapping the side of the valve to see if that loosens the pin. If the pin is stuck down, use a pair of pliers to pull the pin up a few mm (you don't want to bend the pin). If it is stuck up, use something to press down on the pin. If it is sticking, a small amount of WD40 or similar light oil will free the pin. It should move down easily when pressed and spring back up when the pressure is removed.

3. If the body of the valve has a single arrow on it, the valve should be fitted so it points in the direction of flow: towards rad on the flow side (hotter pipe); away from rad on the return side (cooler pipe).

If the body has two arrows at right angles, the valve can go either end and any orientation.

 

[patagonia]

Thanks, but the rads do get hot all the way down and an inhibitor has been added so I don't think it can be sludge. The valves are on the flow so that's OK then, but am still waiting for an answer as to whether they should be set to high or off, if that matters, before removing the head and how to tap the pin.

 

[patagonia]

Thanks DH. I did spray with WD40 last night and although there was minimal movement of the pin, this morning it is only warm on No 1 setting whereas before it was very hot, so some success. Will have a go at the others now and check for arrows. I had read on here or another similar site that one could give the pin a light tap to free it but will do as you say.

 

[Nige F]

Try pushing down on the pin and releasing rapidly - I know it sounds pedantic but I don`t like tapping things- and I don`t like trying pulling the pins up either Open valve up before taking head off

 

[Meme21]

What Nige F says is what I have always been told and should be what is tried first. However, I find that from time to time the TVRs just 'go'. Don't really know the reason for this. I have a couple of radiators at the moment that are just blazing away because the TVRs won't turn down, but the pins are fine. Time to change them.

 

[patagonia]

Thanks, everyone. I think I may have sorted them all now. If not, what is the best make to replace with? And is it really necessary to drain the whole system down to do this as I read somewhere? Can't pipes be frozen? We have the very small bore type.

 

[D_Hailsham]

However, I find that from time to time the TVRs just 'go'. Don't really know the reason for this. I have a couple of radiators at the moment that are just blazing away because the TVRs won't turn down, but the pins are fine. Time to change them.

Changing the valves won't solve the problem, which is caused by incorrect balancing.


The best valves are Drayton and Honeywell.

If you have a combi or system boiler it is possible to change the valve by shutting of the other valve on the rad and the valves on the boiler. You will get a slight leakage from the rad when you undo the connection, so have some plastic sheeting to protect the carpet and rags to mop up the water.

If you have an open vented system you can get a Draineasy kit from B&Q etc. This consists of two plugs which are used to block up the flow and vent pipe in the F/E tank. The water then cannot escape and air can't get in as a vacuum is created. Same as with the system/combi.