I've got an old central heating radiator where the bottom has rusted out over the summer. As far as I can see the panel width is 50" and the pipe-centres 53.5"
Everything for sale is measured in metric (I blame the EU!)
Is the best thing to do, getting one that's slightly wider/narrower, and putting a wiggle in one of the pipes? They come up through holes in a traditional boarded floor, and I don't want to start fiddling around under the floor.
Screwfix are reticent about the dimensions of TRVs, in the sense of how much they add to the width of the panel itself.
Many "modern" radiator fittings don't use a union type connection, but a stubby tail of chromed 15mm pipe and an olive, you can get extension tails, so if you replaced with a smaller rad you should be able to fit it in without wiggly bits.
I think Myson still make imperial sized radiators, don't tell the weights and measures inspector ...
In message snipped-for-privacy@mid.individual.net>, at 12:49:06 on Sun, 3 Oct
2021, Andy Burns snipped-for-privacy@andyburns.uk remarked:
I'm likely to be buying this from one of the local sheds, of which Screwfix is the most obvious. Places like Plumbase and Wolsely appear to recruit staff on their ability to be so rude to walk-up customers they never come back.
In message <sjc7v7$4pa$ snipped-for-privacy@dont-email.me, at 13:33:42 on Sun, 3 Oct 2021, Harry Bloomfield <?.?@harrym1byt.plus.com.invalid> remarked:
Most of the valves I've seen screw into the body of the radiator. And then exit downwards. Hence the need for a wiggle.
I'm a few years retired and even in junior school I was taught SI units.
You can get adjustable length radiator tails.
Screwfix video
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For each radiator size SF do 3 variants
Single panel Double panel single convector Double panel double convector
On a, say 1000 x 600 radiator the Sible panel is rated at 0.948kW whereas the double panel double convector at 1.76kW. You need to size your radiator for heat output rating.
Thanks, that's the sort of thing I was hoping might come to the rescue after posting here.
The heights are pretty much standard, and the width needs to match the piping. The old one[s] - all throughout the house - are double panel single convector, so probably will replace like-for-like.
I've fitted several different brands/models and the distance between the radiator and pipe has always been the same within a mm or so. I find that wholly unsurprising as professionals aren't likely to carry spares which can't be subbed for Drayton and Drayton clones. That wd also explain why Screwfix don't bother with dimensions. But IMLE dimensions are availabl;e if you search for the maker's data.
Yup, traditional style ones where the tail is has a half in BSPT thread on the rad end and a 3/4" BSP male on the valve end are like that. For those you would need to offset the pipe:
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(Example made up with a pushfit on the bottom to make a quick "live" swap without draining down easy)
However many modern valves are no longer like that. They have the same BSPT thread at the rad end, but are unthreaded at the other end - just presenting 50mm or so of chromed 15mm copper pipe. The rad valve then have 15mm compression fittings on both its input and its rad tail connection. (and in fact most can be reversed so that you can orient the TRV head to be horizontal as well as the more traditional vertical.
And it also differs on the height so its not just the length of the tails that need to be taken into consideration but the length of the vertical pipe from the floor (if this is the way the pipe is routed)
The OP needs to go to the TRV manufactures site for the dimensions.
When I replaced old TRV on my system I found that I had to extend the length of the vertical pipe using a straight 15mm coupling and a new piece of pipe - actually shorted the existing pipe first to add a longer piece so the the coupling didn't foul the TRV nut. Water was removed from the pipe with a wet and dry vaccuum cleaner prior to soldering.
As the OP if fitting a new radiator the wall fixing brackets may be different so the new fixings could be slightly higher or lower to compensate for the new radiator and TVR connections being slightly higher or lower than the existing connection.
On the other hand to fit a new TVR and lockshield valve he may/will have to get the olives off the pipes because the nuts on the new TVR/lockshield may not be compatible with the old. Method 1 shown in
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be the practical way of removing an olive in this situation - perhaps using a hammer to hit the spanner.
It does rather depend on the age of the original. When I replaced very old TRVs the difference of the dimensions compared to the modern devices was enough to be a PITA.
I suspect the installation I'm replacing is 20yrs old.
Having gone round various other radiators today, it appears at least two others have seized thermostatic valves, so the scope of the project keeps growing...
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