Retro fitting TRV's - new valve fitting type

[Tony Collins]

OK, I've just bought some TRV's for the upstairs, but they have different fittings from the valves currently fitted.

New valves have 15mm compression fittings and tails for fitting to raditor.

Rads/old valves have union fittings.

Before I drain down and find out I can't fit the new valves easily - what should I expect. Will the old union fittings remove easily from the rads, and what tool is needed?

Will the new 15mm tails have the same screw fitting (into the rad) as the old union types.

Thanks for your help.

[Set Square]

They're probably designed like that so that they can be used either vertically or horizontally - having compression fittings in both directions.

You will probably need an Allen key of the appropriate size for radiator valves. You will need to apply quite a lot of torque if the old tails have been in the rads for a long time. I have a length of steel tube which I slide over the Allen key to increase leverage.

Yes, they will be 1/2" BSP - whose OD is actually nearer three quarters of an inch.

[Ed Sirett]

Yes the old tails will have to come out.

A tool like Screwfix #11467 is needed. However since you are only going to chuck the valve you could simply use Footprints or Stillsons on the old tail. The key however will allow you to get a good positive grip to which you may apply further torque as needed. They maybe a 'little' stiff, heat will help to get the tails out but do nothing for the paint job on the radiator.

At the left hand side you will need to push the wrench toward the wall or get someone to half sit on the rad whilst you pull the wrench up. Even if you have the room don't pull the wrench forward or you may get more than you were hoping for.

[Tony Collins]

Ed, Set?

Thanks for the help - all questions answered.

[John Rumm]

That sounds like the voice of experiance ;-)

[Set Square]

But why do it in situ, anyway? To change the valve, you will have to drain the rad. So why not take the opportunity to remove it and give it a good wash out. Then, lay it flat on a Workmate to change the tail. That way, there's no danger of pulling the brackets off the wall.

[IMM]

This is the safest method.

This still may bend the rad bracket.