We have some decorators in, doing a few rooms. They want the radiators off the walls.
When I've removed rads before, I've always replaces them fairly soon afterwards, so the 'down time' is minimal.
Here, I'm expecting a few days. So I don't want to be without heating or HW for that time.
Will TRVs close sufficiently to form a proper seal allowing me to re-pressurise the primary loop with the radiators off? I'm fairly confident the lockshields will.
Another possibility for some of the rads is to loosen the valve-to-tail nut, and swivel the rad down onto the floor and nip it back up again.
If you have a decorating cap for them, then take the head off the valve and fit that. If not, take the head off, insert 5p, and replace the head. That will ensure the pin remains depressed and no water can leak.
Yup that can work, although you risk pipe damage if they step on a rad.
Don't rely on it. Use the caps supplied with each TRV for this purpose rather than the normal heads.
If you drain each rad individually - with both valves turned off - you won't need to de-pressurise the system. You can safely run the system in that condition, with one or more radiators removed. If you're worried about the valves seeping a bit - and if the valve to tail connections are of the compression type - you can make up blanking pieces with short bits of pipe, each with a compression nut and olive and with a blanking cap on the end. [I've had some for years, with ship halfpennies - remember them? - brazed onto the ends of short bits of copper tube - but copper push-fit end caps are fine.]
If your bleed screws are part of a 1/2" BSP removable assembly, you may be able to get the original water back into the radiator after decorating, so as not to lose the inhibitor or the oxygen-free status. [I always save the water from my radiators (vented system) and pour it back into the F&E tank immediately before re-filling/bleeding them.]
I've never fancied that! If you have an 'accident' while doing it, you could end up spilling a great deal of nasty black sludge!
Last time I relied on a TRV I was sanding off the walls and opened a window to let the dust out, next thing I was standing in a puddle of water! It was that cold weather just before Christmas and opening the window had allowed the room temp to drop sufficiently for the TRV to open.
Clamped hands around the TRV to warm it up, and it closed again.
Use a cap, or coin under the TRV as has been suggested.
I could remove the TRV totally, and use the existing nut and (probably ) non-removable olive on the pipe stub onto a brass cap, assuming the cap has the same thread as the old captive nut.
I've had bad luck with differing threads in the past. Some compression fittings have a coarser thread than others. Probably an age thing. ( the fittings, not me! )
OK, good idea. Thx. Better than loads of wraps of leccy tape holding in the pin.
If the pin is indeed fully depressed, ( with a terrible pain in all the diodes down it's left side ) is that meant to create a pressure-tight seal ( as opposed to a minimal-flow closed-enough seal )?
As others have said, no. Need to replace with the decorator's cap.
I did this for my brother a couple of weeks ago. I found both valves started wobbling on the pipes, and leaking at the joints. Emergency drain down required, and then remake the valve joints, sigh...
IME it does shut it off completely - however that may have been luck[1]. However that is not to say it always does. Having a couple of appropriate sized BSP connectors on capped off stubs of pipe will deal with any that don't
[1] I normally get the reverse problem - ones that shut off and then refuse to open again!
Neighbours of ours went away for a weekend in January the year before last, while they were part-way through a redecorating project in one of the upstairs rooms.
Radiator had been removed and, during a particularly cold night, the TRV (which was thought to be turned off) opened and, ... well, you can imagine the rest.
If you're lucky! The shim will offset the temperature at which the TRV opens by a few degrees - so it will need to be *really* cold to open. But I still cap them off to be safe.
You fit them on the thread which points towards the radiator, onto which the nut on the tail normally screws.
Don't do that - you'd have to drain the system, which is otherwise unnecessary.
Most are either standard 1/2" or 3/4" BSP - although I have come across
*finer* ones on old radiator valves (but not TRVs). All the TRVs I've seen recently use compression fittings between tail and valve, and the threads are standard 1/2" BSP.
But that's *not* the same as saying that all valves necessarily have
3/4" BSP threads. Most, with compression-type connections have 1/2" BSP.
The type of valve which has a conical tail to valve connection has a larger size. Some of these *are* 3/4"BSP but some are the same sort of size but with a finer thread. [The ones with finer threads *also* have finer (than 1/2" BSP) threads on the compression joints to the pipes - which is a right pain when replacing the valve because you can't leave the old compression nut on the pipe. BTDTGTTS!
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