Installing TRV's

[Jupiter01]

I've previously installed TRV's and lock shields on new radiators but I am now attempting to do this on old rads. I assumed it would be the same process until a plumber was suggesting that the "tail pipes may need to be soldered". I think he was suggesting that the old copper pipe may not be the right size (certainly looks 15mm to me!) or perhaps he meant that its been tightened and hence, a new piece needs to be soldered on in order to make a clean fit. Sorry for the rambling.

Can anyone relate to this or give me a heads-up on what may await?

 

[Hot&Cold]

a plumber was suggesting that the "tail pipes may need to be soldered

Has the plumber seen the radiators or was it internet advice ?

Decent plumbers are quiet busy at this time of year,maybe get the work done in the summer. There will be some plumbers working in the summer but many take the summer off and enjoy a relax on their sunseeker

 

[Jupiter01]

It was internet advice after I told him that I may attempt it myself. I explained that I set-up approximately 10 radiators in my own house (fitted trv and lock shield and the the flow and return before hanging on the wall) and perhaps I can do this myself. He was adamant that this wouldn't be the same as they are old/existing radiators. It was at this part of the conversation that he suggested that the pipes sometime have to be soldered...

I would like to do myself if that seems sensible?

 

[fixitflav]

It was internet advice after I told him that I may attempt it myself. I explained that I set-up approximately 10 radiators in my own house (fitted trv and lock shield and the the flow and return before hanging on the wall) and perhaps I can do this myself. He was adamant that this wouldn't be the same as they are old/existing radiators. It was at this part of the conversation that he suggested that the pipes sometime have to be soldered...

I would like to do myself if that seems sensible?

The bare rad will have holes threaded 1/2"BSPF (maybe not if it's very old). All the TRVs I've seen have 1/2"BSPM tails so will go straight in. If the rad has an existing fitting, remove it, but that might be easier said than done, a whiff of heat would help if it's reluctant.

 

[Jupiter01]

Thanks. so you don't see any need to solder as part of this?

 

[ollski]

Sometimes microbore straight out of the wall needs to be lengthened as the ends will be crushed by the olive...guaranteed. My personal preference on these is to drop the rad slightly....unless someone knows of a deeper brand valve?

 

[fixitflav]

Thanks. so you don't see any need to solder as part of this?

The fitted TRV might not marry up to the existing pipework. If not the pipe needs modifying, probably involving soldering.

 

[Jupiter01]

Perhaps I've missed something in my earlier post.
I currently have radiators connected and working. They have been in place for at least 15 years (when I purchased property). All these rads have copper tails fed from the bottom. I am assuming that this is 15mm copper as its definitely not 10 or 22mm.
If I want to replace the current lock shields with TRV's, why may this require soldering?

Thanks for your help.

 

[fixitflav]

Perhaps I've missed something in my earlier post.
I currently have radiators connected and working. They have been in place for at least 15 years (when I purchased property). All these rads have copper tails fed from the bottom. I am assuming that this is 15mm copper as its definitely not 10 or 22mm.
If I want to replace the current lock shields with TRV's, why may this require soldering?

Thanks for your help.

The dimensions of the TRVs may not be identical to the existing iso valves. My rads are probably about 30 years old, most with TRVs, and iso valve on the other end is different. The iso has a shorter tail into the rad, with an internal hexagon, 13mm if I remember right, to turn it into the rad. The TRV tail is longer with spanner flats. On the iso valve end the c/l of the pipe coming up from the floor is 38mm from the end of the rad, on the TRV end it's 45mm. I believe modern iso valves have similar tails to TRVs, so the distance 45mm is probably the same, but I haven't got any so I can't measure it. If you have that type of iso valve the TRV should go straight on. If it's the older type you'll likely need to do some mods. That's my take on it anyway.

 

[oldbuffer]

This is my opinion, not a guarantee, and assumes you have standard 15 mm copper pipework to the radiators:

1. The chances are the TRVs and new lock shields will fit on where the old valves were without modification, although you'll probably have to change the tails (which will come with the valves).
2. There is a risk that your pipes are imperial 1/2" rather than metric, but you can check that in advance. If so you will need to modify the pipes and soldering will be required.
3. If your current valves have union nuts (not compression) to connect them to the tails, the pipes coming up from the floor may be too close together. With care, and not overdoing it, you can shorten the tails for the new valves with a hacksaw. If you do, clean up the cut edges with a file.

 

[Jupiter01]

Thanks. a couple of follow-up's please:
- how do I check if I have 15mm or imperial pipes?
- if they are imperial, is there a solder fitting which converts from imperial to metric?

 

[oldbuffer]

1. Measure the diameter (you'll need a vernier caliper). 15 mm IS 15 mm outside diameter, 1/2" is a fraction over. You can often get 1/2" pipe into 15mm fittings, but you may have to file it / sand it slightly to reduce the diameter without making it out of round. Alternatively, try and fit a 15 mm solder fitting to the pipe. If it is very tight / won't quite go on, the pipe is imperial.
2. Yes, look at Screwfix 69948

 

[fixitflav]

Thanks. a couple of follow-up's please:
- how do I check if I have 15mm or imperial pipes?
- if they are imperial, is there a solder fitting which converts from imperial to metric?

Couple more queries
Can you confirm it's an existing installed rad and you just want to add a TRV?
You haven't mentioned renewing the other iso valve, I assume you want to leave that as is.
Can you measure the dimension I referred to earlier, and compare with the TRV?
If the dimensions are OK, the TRV might go straight on, but that assumes the compression fittings on the existing pipe match the TRV. Modern 15mm compression always uses 1/2"BSP, but older ones were sometimes finer thread. I have some of each.
If the threads are right, you should be OK even if the pipe is imperial 1/2", as it should go into the compression fitting. But worth checking first - measure the pipe OD and if it's 1/2", the valve ID.

 

[Harry Bloomfield]

My rads were all installed in around 1983. Last March, as a new boiler was to be fitted and I had bought the Drayton TRV4's years before, I decided it was time to fit them. They just went straight on directly in place of the ISO's, size and threads were identical, I even left the tail undisturbed, rather fit the supplied chrome tails.