I've got one more plumbing question that I'm sure I'll get an instant answer
to on here :-) - I've look through the archives and can't really find much
on the subject.
In the process of installing a new bathroom, from scratch, I need to take a
feed for the hot and cold water from some existing pipes under the floor
(which used to lead to the old kitchen taps). The trouble is I'm in an
upstairs flat so can't afford to risk water spillage when I cut into these
I could attach a hose to the lowest tap in the house, stick it out the
window and attempt to siphon the water out the system, but I really can't
see this working. I haven't heard great things about pipe freezing kits,
and even then I still need an area of dry pipe to solder the new connections
Any tips for a task like this?
Drain what water you can from the system by conventional means, then arm
yourself with lots of old towels and some small shallow trays if you can
find any that fit (foil food trays can be good) and a bucket. Line area
under pipe with old towel to catch drips, and place tray under pipe.
Make a small nick through the pipe with a hacksaw. That way you can
control water egress by sticking your thumb over the hole (if you dive
straight in with a pipe cutter you may end up with more than you
bargained for)! Then just fill a tray, stop the flow of water, empty and
replace. Keep going until the pipe is empty. Remember you may get a
little extra out of the pipe when you finally cut through.
Cheers John - I was afraid that might be the case :-). Think I'll put some
plastic sheeting under the towels too - just to be on the safe side. I've
got approx 4" between the pipes and downstairs' laths so should have enough
room for the trays.
Just thinking, I've capped off the old kitchen tap pipes which are in the
same room (kitchen becoming bathroom) - these need to come out 'cause
they're in the wrong place but I've just put compression fit end-caps where
the taps used to be for now. I wonder if I turned the water off, opened the
current bath taps (bathroom becoming kitchen) and removed the end caps from
the old kitchen taps whether I could blow some water out the system? The
pipe run between the two points is probably about 15m. Or is this a silly
It is unlikely to get all the water out, although it may shift a bit
more... Oh, and you will probably need to use a compressor to supply the
air! (using for example, a air duster nozzle and a cloth round the pipe
to create a airtight (ish) seal)
As far as cold is concerned, turn off the water at the main stopcock
(probably under the kitchen sink) and open a downstairs *and* an upstairs
tap. The pipework will drain through the downstairs tap, with air being
admitted through the upstairs tap.
With the hot system, you have to remove the pressure by stopping cold water
getting from the header tank into the hot cylinder. Hopefully there will be
a tap or gatevalve in the cold feed to the cylinder (the one which comes
down from above and goes into the *bottom* of the cylinder. If so, turn that
off and then open an up and a down hot tap - as for cold - to drain the
pipework. If there *isn't* a valve in the cold feed, you'll need to reach
down into the header tank and stuff a tapered cork into the outlet pipe.
[Choose one of a size which leaves enough to catch hold of to pull it out
again when you've finished!]
Sorry, I missed the 'flat' bit - and assumed you had access to downstairs.
Do these pipes feed anything below, or not. If so, what I said is ok - if
you negotiate with the person below.
If not, and if the pipes you are breaking into are at the lowest point,
you'll have to use towels and trays as suggested by someone else to collect
the water in the pipes having first turned everything off.
We're on a separate water supply to downstairs. :-)
To be fair that's a recent development - it was shared with downstairs -
what a nightmare that was by the way... we actually have water pressure
now - woohoo!
i was soldering a hot water pipe and couldnt stop the trickle of water
from the pipe, i did exactly as you suggest,blew down the pipe, it
worked. Any water left in the pipe will make a good soldered joint very
difficult if not impossible to make, you might consider a push fit
fitting for your final connection.
A little wetness is usually ok, it will soon boil off. A continuous
trickle however is likely to mess it up.
In those situations the old trick of stuffing a ball of fresh bread up
the end of the pipe will usually halt the trickle for long enough to
solder it. It will wash out the pipe next time you turn a tap on.
With it being a flat, I'm slightly nervous about having compression or push
fit joints under the floor, especially since it will be tiled upon and a
right b*****d to lift at a later date. I was planning on having pretty much
all the plumbing boxed in above the tiles (so my task with these water pipes
is to get them popping through the floor at a convenient point, from which
point I can feed them 'round to the shower, bath etc.). Hence wanting to
make it a solder connection if possible, although know what you mean - might
be difficult to get a dry piece of pipe to start on - here's hoping! :-)
Some people would suggest the "bread" technique. This basically means shove
a bit of bread up the pipe to dry the pipe out. Then solder. The bread
quickly degrades and is "potable".
In my case, however, I've had perfectly acceptable results without
bothering. I use a good proper sized torch, though. Not a little taymar
intended for paint stripping. Obviously, get as much water out as possible
I've just had another thought!
If you're inserting tee's into the existing pipes, you'll have to cut a
short section of pipe out. Suppose you get a couple of those self-piercing
washing machine taps (can you get them for 22mm pipe if necessary?) and
install them temporarily where the tee's will go.
You can then use the taps to drain the pipes - under controlled conditions -
into shallow trays. Finally, when no more water comes out, remove the taps
and cut out the pierced section of pipe.
How does that grab you?
And resolve never to throw away the foil trays that
some frozen food is sold in. They come in very handy for such jobs
including, but not limited to draining washing machines
-when the pump fails even if it's only fluff. Because such
foil-trays tend to be shallow -and awkward to handle / lift
when half-full; it's useful to have several so one can be
receiving drainage while the other is being emptied.
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