I need to remove my old kitchen sink and move some of the pipe work.
Will I have to drain the hole system to do this ? (I think I have a Y
Plan system) If not what do I need to do to stop the water?

I will also a some point soon need to move a rad and pipework will I
have to drain down for this?

Have not done much work on CH so easy to follow instructions would be great.

Thanks

Paul

In an earlier contribution to this discussion,
Paul wrote:

I need to remove my old kitchen sink and move some of the pipe work.
Will I have to drain the hole system to do this ? (I think I have a Y
Plan system) If not what do I need to do to stop the water?

The water which comes out of the hot tap of your kitchen sink is (or should
be!) entirely separate from the water in your heating system. The closest
they get to each other is inside the hot water cylinder - where hot water
from the boiler flows through an internal coil/heat exchanger, and heats the
domestic hot water without the two lots mixing. So, to work on your sink,
you *won't* have to drain the heating system. But you *will* have to stop
the hot and cold water flowing to the taps.

The cold tap is probably straight off the mains - in which case you simply
need to find the main stop-cock and turn it off. Water may still come out of
the tap for a bit after turning off the stop-cock, because it will be
draining back from the pipes which go upstairs. So give it time to stop
before disconnecting the pipework.

When you open a hot tap, water flows from a cold header tank (probably in
the attic) into the *bottom* of the hot water cylinder, pushing water out of
the *top* connection of the cylinder - which feeds the taps. So, to turn off
the hot water, you need to stop water flowing from the header into the
bottom of the cylinder. Hopefully there is a tap or gate valve in the feed
pipe which goes to the bottom of the cylinder. If so, turn it off. If not,
you'll either have to tie up the ball valve on the header, and let all the
hot water run away until it empties the header and stops running - or you'll
have to interrupt the flow in some other way. One possibility is a cork in
the outlet fitting at the botton of the header tank. Use a tapered one,
which leaves enough to get of hold of to remove it when you've finished.


I will also a some point soon need to move a rad and pipework will I
have to drain down for this?

You will have to partially drain the heating system for this. After turning
off the whole system at the FCU, drain the radiator, as follows:
Turn of both radiator valves. [If one is a thermostatic valve, remove the
head and fit a positive stop cap which holds the pin firmly down at all
temperatures]. Partially undo one of the union nuts which joins its valve to
the tail (the bit screwed into the radiator). Catch the water which comes
out. You will need to have handy a bowl or bucket big enough to hold the
entire radiator contents - but you'll need smaller containers which will
slide under the valve to actually catch the water - I find aluminium
take-away food containers good for this. You'll also need to protect carpets
etc. with plastic sheeting and old towels - black stains from central
heating water are almost impossible to remove! Work on both sides of the rad
(one side at a time) until no more water comes out, then disconnect the
union nuts completely. You can then lift the radiator off its brackets.

You still have to drain the pipework before you can work on it!

Besides the large cold water header tank, you will have a smaller fill and
expansion tank which feeds the primary circuit - that's the bit you want to
work on. Put corks in the outlet connector at the bottom of this tank, *and*
in the end of the vent pipe (the pipe which curves over the top of the
tank). Close both valves on all other radiators in the house, to keep the
water in. [If the system has ever been balanced, count and record how many
turns it takes to close each lockshield valve so that you can put them all
back to the same position]. Then go to the removed radiator position, and
open each valve in turn - catching the water which comes out in a container.
When no more water comes out, you can disconnect/modify the pipework.

If your system has inhibitor in it (which it should!) save the water you
drained out, and pour it back into the F&E tank before allowing water to
flow into your neaw pipework/radiator. But let it stand for a while first,
so that any black gunge collects at the bottom - and stop pouring just
before you get to the black stuff.

HTH.
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What a great idoits guide you have done for me

Thanks

Paul

Sorry to butt in on this one but one thing the helpful poster didn't mention was how to bleed the system when the sink is replaced?? Chances are on this system water will not flow from the hot tap when it iaa
s all connected back up because of airlocks.
Ideally if you are fitting a monobloc tap then just hold your hand over the spout and turn on hot and cold taps until the flow reaches back to the header tank.Don't hold on too long to prevent blowing the cylinder.
There is maybe a safer way of doing this but i have never had any problem this way.

If you have a conventional system with header tank and intend to perform short duration work moving your rad it is possible to perform the task live using BUNGS,,They cost £15 at the plumbing store and have instructions in the pack...

at a wee bit more expence you could buy a freeze kit at again do the job live.

a full drain down could result in air locks

if in doubt get a nice quote from BGAS

In an earlier contribution to this discussion,
gastec wrote:


if in doubt get a nice quote from BGAS


But only if you've got more money than sense!
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