I have done some re-piping of my radiators as part of moving to a combi
boiler. As the new stuff will be pressurized, is it a good idea to
subject the old, in *good* condition, radiators, old and new pipes, to a
mains water pressure test?
I will temporarily install a small stop valve in case of problems, which I
do not anticipate.
Dave Fawthrop <dave hyphenologist co uk>
"Intelligent Design?" my knees say *not*.
If your mains is like mine, it will be at about 4 bar. The normal operating
range of the system will be between 1 and 2 bar - and it's good to test at a
higher pressure (provided you don't overdo it!) to make sure you've got a
AIUI, many new radiators are factory tested at 10 bar - so they will
certainly stand 4 bar if they're ok. If they're not, 4 bar should show up
any rusty pinholes which may be developing. The pipework is presumably very
similar to that used for your domestic cold water water supply - which
clearly *has* to stand mains pressure.
In short, I don't see a problem with what you're proposing.
If you are replacing the boiler, it would be a good time to remove the
radiators, take them outside, and give them a really wash out with a
hosepipe. If I were doing it, I'd rig up a means of doing an initial
pressure test on each rad whilst it is outside before testing the whole
Neither do I, with the proviso that you completely bleed the system before
raising the pressure too high.
If you *do* have something fail at 4 bar, it would be a lot cleaner and
safer if you didn't have a load of compressed air in the system at the same
Hmm... I'm not sure I should admit to this but here goes...
NB - This was a long time ago when I was very young....
This is my one and only failure ever with DIY plumbing..
Mixer tap in kitchen was playing up on the hot water side.
I reseated, cleaned/greased all the bits to no avail. I came to the
conclusion that it was an air lock - there are some horrid flat runs
to the kitchen...
I decided to pressurise the hot side using the mains. Impossible at
the kitchen tap by virtue of the design of the mixer tap.
I went to the loft and 30mins later the hot water overflow to the header
tank had a gate valve on it, and the mains was temporarialy tapped into
the hot system behind a stop valve ...
With my wife in the kitchen I gently opened the stop valve...
"Coming through yet?" ... "No... Well... Err.. " (typical :-)
open the valve a little further... then a little further... hmmm...
why ain't this working ?
Then - slight creaking noise from the hot system... decide that's
enough and lets turn off the stop valve... too late! Boom! ......
in fact almighty BOOM !!!!!
Stop valve turned off - go to explore....
Turns out that the hot cylinder in the airing cupboard had decided
enough was enough... You may have noticed that the bottoms of
cylinders are concave... Not any more on this one... Convex. - not
only that but the cylinder had moved up by six inches... all the joints
to it were now at a slight angle !
Lucily there was not a single leak.... I spent the following day replacing
the cylinder... It did actually need replacing !!!
I realise your situation is a little different but BEWARE...
Oh - the tap... yes - fixed by replacing the tap... it was knackered...
Dare I ever post again to this NG.... :-(
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