Radiator valve size

[mahutchinson]

We had an installation by Glowarm two years ago (disappointing quality compared to a similar job on our previous house but that's another story). I now need to remove a TRV in the box room and replace it with a normal valve head as it is in the way of the large skirting board I am about to fit (reason for the large skirting is to accomodate electric sockets which have no slack in the wiring to place higher). However, I am puzzled by the size of the connection with the radiator as it appears to be 15mm, like the pipe size, but all the valves I can find for sale have a larger diameter. Are these some sort of non-standard radiators ? I believe that they were ordered from a local supplier especially for the job which is presumably the norm.

 

[Whitespirit66]

Are you talking about the connection between the rad and TRV. There are two types of connection between rad valves and the tail (the fitting that screws into the side of the rad. The larger ones are gland unions. It sounds like you have the 15mm compression fitting type.

Unscrew the nut securing the tail to the valve and slide it away from the valve a bit. If you can see a copper/brass olive on the end of the tail, then you have the 15mm compression type valves and TRVs.

A pic would help.

 

[Whitespirit66]

Re. the problem with your cable not being long enough for you to raise the sockets. Can't you join some extra cable on?

 

[mahutchinson]

They do appear to be 15mm connection - the problem is I can't see valves with 15mm connections to the radiator on any supplier site.

Regarding the cable slack, yes I could add an extension if it was for one socket but it is likely that every socket in the house has this problem and so I prefer to standardise them with similar high skirting and simply fix the sockets in the skirting as I don't think it would be advisable to put an extension on every single socket and I don't want to pay to have the whole house re-wired.

 

[TicklyT]

The tappings in the radiator are usually a standard 1/2" BSP female thread, but there are different types of insert that fit into the tappings to match different types of valves. these are usually supplied with the valves, not the radiator.

Some use a large union nut, and some use a 15mm compression fittings.

http://www.screwfix.com/prods/75592/Plumbing/Radiator-Valves/Terrier-Wheelhead-Valve-15mm-x

 

[Whitespirit66]

Most TRVs are 15mm compression fitting these days.

Eg.

http://www.screwfix.com/prods/25900...es/Drayton-RT212-White-Chrome-TRV-15mm-Angled

 

[JohnD]

if you can afford a Drayton TRV4, which is good quality but rather expensive thermostatic valve, you will find it does not have a great wide thermostatic head, and may fit with your new skirting. It will come with a new tail, and with a radiator wrench you can unscrew the old tail from the rad and fit the new one (using PTFE tape on the threads to seal it)

Get one with a 15mm to fit the copper pipe, and the tail will fit the screwed hole in the radiator. If you buy half a dozen or more you will get them cheaper from an online supplier.

http://www.screwfix.com/prods/26100...ves/Drayton-TRV4-White-Chrome-TRV-15mm-Angled

p.s. if you mention your Socket positioning problem on the UK Electrics forum here, there is a way it could be done - but to do it safely and reliably you need the correct tools and parts. It has long been considered unsafe to put electrical sockets on skirting boards as they are prone to damage from hoovers, furniture and feet. Modern standard is to put sockets at a height of 450mm to 1200mm above the finished floor.

 

[mahutchinson]

I understand the point about inserts to fit different fittings but surely this makes the vertical length too long to fit the radiator ? The Honeywell TRV supplied by Glowarm has an extremely short connector to the radiator and anything longer would require the connecting pipe to be moved outwards. I certainly don't want to do that as I have just completed a laminate floor. Whatever goes on there must have a siimilarly very short 15mm fitting.

 

[dextrous]

I find these references to "unions", "too short", "too long" and the implied male anf female fittings both mysogenist and homophobic, and as such, offensive.

 

[Whitespirit66]

I understand the point about inserts to fit different fittings but surely this makes the vertical length too long to fit the radiator ? The Honeywell TRV supplied by Glowarm has an extremely short connector to the radiator and anything longer would require the connecting pipe to be moved outwards. I certainly don't want to do that as I have just completed a laminate floor. Whatever goes on there must have a siimilarly very short 15mm fitting.

You don't need to move the copper pipe that comes through the floor. You can get adjustable radiator tails to replace yours. They slide in and out according to the distance between the copper pipe and the rad. They come in compression and union variants.

http://www.screwfix.com/search.do;j...ator+tails&searchbutton.x=10&searchbutton.y=3

 

[JohnD]

but if the pipes come up through a wooden floor (not cast into concrete) they probably have a bit of slack to move them around enough anyway. they are probably sitting in roomy notches in the joists.

 

[bengasman]

Re. the problem with your cable not being long enough for you to raise the sockets. Can't you join some extra cable on?

No you can not. Legally that is.

 

[JohnD]

p.s. if you mention your Socket positioning problem on the UK Electrics forum here, there is a way it could be done - but to do it safely and reliably you need the correct tools and parts. It has long been considered unsafe to put electrical sockets on skirting boards as they are prone to damage from hoovers, furniture and feet. Modern standard is to put sockets at a height of 450mm to 1200mm above the finished floor.

There is a way.

 

[mahutchinson]

but if the pipes come up through a wooden floor (not cast into concrete) they probably have a bit of slack to move them around enough anyway. they are probably sitting in roomy notches in the joists.

They would have if I had not just finished the aforementioned flooring !

Thinking the pipes are in notches is optimistic, unfortunately. The guy that owned the house previously had most of the pipes almost completely unsupported, in line with the quality of most of his work. His profession was.....property maintenance !

The adjustable tails I didn't know about but surely if Honeywell make a TRV with a very short 15mm connection, as I currently have, it must be possible to buy an equivalent standard valve with the same very short connection ?

 

[dextrous]

Re - cabling

Assuming all sockets are part of a ring circuit, think it would be ok to put a multiblock in the existing pattress and run the new, higher sockets as spurs from these. The existing pattress on the skirting needs to be covered with a blanking plate.