In my ham-fisted efforts to fix a sticking TRV, I've gone & pulled the
pin out of the valve. It wouldn't push in, so I thought, "I'll give
it a light tap with a hammer"!
Does anyone know a quick way to replace a TRV without draining the
"You know, I'd rather see this on TV,
No help to you, but I just had the same problem (Mum-in-Law's house) but
didn't have a hammer to hand (fortunately).
TRV wouldn't open, I tried pushing the pin down, then lifting it with the
plier attachment on my Swiss Army Knife.
Pin freed off a treat and is now working fine.
I was just musing how much a plumber would have charged :-)
P.S. if you swich the wires over on the pump and run it backwards at full
speed it will suck the water back instead of pushing it out.
You will have to bleed the system afterwards to get the air out, though.
No - really - don't try this at home kiddies :-)
On Thu, 16 Oct 2003 19:32:20 +0100, email@example.com wrote:
I haven't had the courage to do it myself, but as I decorate each room,
I've been getting our village plumber to come and change the valves on
each rad. He does it live, drains the rad, spreads two or three towels
under the valves, releases the glands on the rad then the compresssion
nut, whips the old valve off, pops a new one on and does up the
compression nut. Takes him literally twqo or three minutes to do once
the rad is drained.
I reckon he loses about half a cup of water - as the room is cleared for
decorating at the time and no floor covering down it's not too much of a
problem. All you need to be certain of is that the new valve is closed
and that the old and new fittings are both 1/2" bsp thread for the
compression nut. I think some older fittings were different thread size.
Reminds me of the days - yup, I used to do it, prolly around the 60's, when
we changed tap washers without draining, just whipped off the top, muffled
the hole with rag or summat, bunged a new washer on the jumper thingy,
rammed it back.
Isolators everywhere - they dont know they're born.....
Had to replace my house's stop cock this way. Old one wouldn't turn off.
Couldn't find the street one. Thames Water would have taken a week to turn
off the street and informed all our neighbours that it was our fault.
You could turn the flow down a bit with the existing stop cock. I was
surprised how little water came out really, if you're really quick jamming
the new valve on. The old valve is still on the line. It opens fully OK,
just doesn't turn off. The kitchen was (still is) the process of refitting
and there were a few missing floorboards around the valve, so the water
everywhere wasn't as bad as it would have been in a bedroom with fitting
I'm missing something here I think. The valves are on the piping side
of the feed to the radiator, so taking a valve off means that you are
exposing the whole system to producing a flood.
Are you saying that he removes the valve from the pipe to do this job?
Sounds that way, but I just want to be sure before I give it a
Yes, it can be done. If you have everything prepared before you start the
job, then keeping pressure downward on the valve, against the pipe and
olive, while you undo the compression nut. Then you'll hardly spill a drop.
Once the nut is fully off the old valve, you quickly grab the new one, which
you've already removed the nut from, and replace it on top of the pipe. You
then keep the pressure downward on the new valve until you get the nut done
As Wanderer says though, it is better to have plenty towels around to catch
the drops that do escape.
It`s also useful to havea couple of old plastic 6 pint milk cartons laid on
their side with a large hole cut out.
They can then be pressed up against any leak and catch a lot of water.
As for working on a Live central heating system , I believe that Drayton ( who
make the TRVs) do a pair of rubber bungs which you put in your CH header tank
to prevent any leakage whist changing valves etc.( no good for combi systems
Giving things a Big Wallop with a hammer is my job. :-))
The only way I can think of, is for you to drain the system down and do it
safely. You might get away with replacing just the head containing the pin
(valve) assembly, but you'd have to be really quick at changing it over when
you see the water beginning to dribble out of the old valve.
If you have a feed/expansion tank, you can get large bungs to block up the
feed and expansion pipes. Then, if you are lucky, you can open the system at
one point and have little drainage. With a sealed pressurised system, you
might find that first draining off enough to empty the expansion tank is
enough to do the same trick.
Always have plan B available, which means you have the water shut off to the
tank and a hose ready attached to the drainage point, someone standing near
the drainage to turn it on when you scream and a bucket and rags near the
valve to be replaced.
Also, if you try doing two radiator valves at a time, there will be tears
before tea time.
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