DIY Doctor UK DIY Forums

I have in the past installed Drayton TRV4s on a number of radiators on the 1st floor of my house, which has a suspended chipboard floor. My previous TRVs (not Drayton) had bodies which screwed into the bottom of the radiator using a large allen key, whereas the TRV4 has external flats onto which an adjustable spanner can be used. This meant that the TRV4 body is longer than that on my previous TRVs, resulting in the two copper water supply and return pipes having to be moved apart to some extent before connection. This didn't present a problem upstairs, since there is a considerable amount of lateral movement on these pipes under the floor boarding.

However, we have concrete floor downstairs and I am facing the same problem but in different circumstances. Of course the copper supply pipes have very little movement in the concrete and I'm finding with the Drayton TRV4 that the distance between the centre lines of the TRV4 and the lockshield valve at the other end of the radiator is greater than the distance between the centre lines of the two supply pipes!

The copper supply pipes only protrude from the concrete some 6 - 8 inches, so have little or no flexibility in them. I could insert a pair of soldered obtuse elbows into the pipe to offset it, but the offset may then be too large.

Must I face the fact that I cannot use the Drayton TRV4 under these circumstances and look for an alternative that has the allen key body fitting?

that would be the easiest option and would look better, to get valves the same size as the existing.

If the pipes are not visible you could cut the pipes and solder new fittings and bend offsets in the pipes, or solder on 15mm-10mm reducers and use 10mm pipe which has more flexibility.


Hope this helps

Would it not be possible to cut the copper back,solder a straight socket on with a new piece of copper bent to fit the new trv

Thanks for the replies guys.

I do normally shorten the supply pipes, fit straight soldered connectors with short extension lengths of pipe to connect to the valves so that, should there be a need to replace a valve, the olive can be tightened onto a new piece of pipe each time to ensure a watertight fit.

The offset we are talking about is probably not more than 8mm. It's too much for the existing pipes. I've not tried bending copper pipe before (and wouldn't try) but I'm wondering whether it would even be possible to bend 15mm pipe first one way then the other in such a short distance. Seems doubtful.

htg engineer - you say "if the pipes are not visible" - well indeed they are but I don't understand why this is relevant. Perhaps you are concerned from an aesthetic viewpoint. I'm not. Your reduction proposal is one I hadn't considered or even realised was possible. Still not sure there is enough ground height (6 - 8 inches) in which to bend even the smaller pipe, let alone achieve the relatively small offset involved.

May just have to resign myself to changing the Drayton valves for ones designed with the allen key screw in body. Can anyone recommend quality valves other than Drayton?

Yes I was meaning how the pipework may look if it was visible. Pegler are a good make, all i use are pegler terriers. The pegler Belmonts I think would work for your situation.

hope this helps