Swapping the TRV to the other side of the radiator

[Chasingsquirrels]

I want to swap the TRV to the other side of the radiator as ice got a new sofa which butt's up against it and I don't think it's a good idea in terms of lack of air flow around the TRV - basically the TRV is "trapped" between the radiator and the side/back of the sofa.

I know it's an either way TRV (proper name escapes me) as it was banging when it was fitted (it's in an extension) and they swapped the existing one for the new either way one. The whole heating system flow has since been reversed as the idiot who fitted our new boiler a few years later connected it the wrong way round! We didn't realise until winter came round and ended up having the TRV's on the non-either way flow radiators swapped round.

Anyway, what I need to know is whether the while system needs to be drained down to swap the TRV's round (my memory is that's what they had to do) or whether it is a DIY job?

whole system (not while system)

Ideally the sofa will be all the way back against the wall, which traps the TRV in totally, but I need to get the curtains shortened so at the moment it's pulled forward slightly so the curtains can hang behind it.

you probably can. It looks like a modern one, which will fit on either flow or return pipe.

to find out which is which, turn the heating off and let it go cold. Then turn it on and rush to this radiator, feel the pipes and see which heats up first. That is the "Flow" pipe. Write an F on it with permanent marker.

With luck the lockshield on the other end will be the same make and rage and will fit the existing nut and olive.

Look for the maker's name to you can identify the valve and look up the instructions. It might be on here
www.screwfix.com/c/heating-plumbing/thermostatic-radiator-valves/cat831012?cm_sp=managedredirect--plumbing--trv
I don't think it's a Danfoss

Thanks PigletJohn.
It is defiantly flow or return as it was fitted to replace the original one way one I'd had put on which was put on the wrong side.
My question is more whether the system needs draining down to do it (which I'd get a plumber in for) or doesn't and therefore could i atempt it myself it is it all too difficult and I might as well get a plumber anyway.

has your boiler got a pressure gauge on it?

Yes you do need to drain as the valve is the bit that could stop the water.
Although when I was at uni the landlord changed the valve on the radiator next to my bed (ground floor) without turning anything off. It was interesting carrying a radiator full of black water out to the front street, and then later watching a fountain of the same water briefly shoot up somewhere towards the ceiling as he switched it over frantically...

Yes it has a pressure gauge.
I did think it would need draining down. Pah.

And thanks

As it has a pressure gauge it is a sealed system. So once you have released the pressure it will not leak provided you only remove one valve at a time (because air cannot enter to displace the water).

It will be safest if you first buy a spare lockshield valve of the same brand as your TRV (so that it will be a direct swap and will fit).

You will need a large and a medium adjustable wrench. These are widely available in set of three in hardware shops. You don't need a good quality set for this job.

You will roll the carpet back so that it is at least six feet from the radiator and your buckets. You will throw down four old bath towels.

You will shut both valves tightly, and loosen the big nut that connects the radiator valve to the radiator tail. Some water will come out. Then it will stop. You will catch it in a large flat grill pan or similar container. You will then undo the nut some more. More water will glug out. Because you have shut the valves at each end, no more water can come out than is contained in the radiator. Maybe it will be a bucketful. When you grill pan is full you will slide it out and slide in another grill pan, while you empty the first one into a bucket. When water stops coming out you will fully undo the nut and wobble the corner of the radiator. You will then place your second pan under the other end, and loosen the big nut. When you have fully undone it and pulled it away from the valve, you can lift the radiator slightly at one side. Filthy black sludge will run out of the other end. Then settle it back.

The next episode will be loosening the compression nut under the TRV enough to turn it so it faces out. Are you ready for that?

btw if you ever take a radiator off, immediately turn it upside down. The openings will now both be at the top so it will not dribble water and sludge while you carry it around.

Right PJ - I'll get a plumber