Our central heating system doesn't appear to have any drain points in it
apart from possibly on the boiler (which is about 6' off the floor). We've
a suspended ground floor with pipework running under the floorboards.
Without actually taking up all the floorboards around the 3 downstairs
radiators to check that someone installed one - I'm a little stuck.
So - assuming for now that there aren't any under the floorboards - what
should I do to drain the whole system?
I'm planning on adding TRVs sometime, so I'll just fit lockshields with
draincocks on when I do that. However I've found a leak on a solder joint
going to a radiator in a room we're decorating. It's been there since we
moved in, but we're going to put down a new carpet - and don't want to that
if I'm going to need to take it up again to lift the boards to repair the
pipe, let alone if its going to stain the carpet before I do that!
Depending on how I feel - I may well do all the jobs at the same time -
however I just need to get the water out the pipes first!
I know that trying to solder a joint which has any water in it may well
fail - however what about compression joints? Do these need to be
completely dry before making the joint?
To send email to me - remove references to NoSpam, and Spammer from my email
No, in fact you can fit them on pipes with water flowing out of them, which
I have taken advantage of several times recently. I'd put an isolating valve
on the wrong way round, so I closed it, closed the valves on the
radiator on the right hand side of it, and then undid the right side. Bit of
water came out. Undid left side, keeping it pressed left, then
swapped it quickly, and did it all back up. Caught all the water in a tray.
No, compression joints can be done whilst wet. Good job really when we added
a new working stopcock to my system that didn't have one...
Don't bother with jointing compounds or PTFE. Compression joints should be
made without either, so you rely on the metal to metal bond, rather than
some organic compound that might break down over the decades.
P.S. I have successfully soldered pipes (15mm, never tried 22mm) with
containing water. Drain off what you can (it wicks away nicely with lots of
bog roll). Then use lots of water soluble flux and a f*cking big torch. No
guarantees. I've never used the bread trick, but am told it can work.
If you want to get *all* the water out, you'll need a drainpoint at the
lowest point - under the floorboards. In my previous house, which had
suspended floors downstairs, I fitted a stop-tap under the floor (accessible
through a small flap in the floorboards) with the output pipe going out
through a vent brick - so that I could collect the water outside.
The pipes need to be completely dry to make soldered joints - but this
doesn't apply to compression fittings nor, I suspect, push-fits.
I recently did what you are trying to do by using one of those self
cutting taps used for the garden hose system. Stick a long washing
machine hose on it and i can drain it straight outside, no trays or
Hmmm.... very very neat idea!!! I like it! Easy enough to do under the
floor too at (pretty much) the lowest point!
Thanks for that.
As an aside - is there any problem with running a CH pump with no water in
it? Not that I've done it, but I just wondered.
Okay... any idea where I can get these cheaply? I've seen one at Screwfix
which appears to have a washing machine hose thread on it - are these the
same as outside tap threads? I doubt it. I've got garden hose fittings for
screw taps which would be nice and easy to reuse.
Outside tap fitting sets from Hozelock, Gardena etc. come with various
adaptors because there are various sizes used on outside taps.
However, the 3/4" washing machine size is one of them and quite
You can get washing machine taps and outside tap fitting kits using
this "tapping in" method from the DIY stores.
Thanks - that's good to know. I had (bizarre) visions of pumping the water
around to possibly drain it faster - however, I also realised that it was
likely to run dry quickly. Good to know that its not something I should
try. Not even sure if it would have done much benefit anyway - certainly
not going to experiment!
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