Draining Combi boiler .. not CH

I am removing the kitchen units and have to move two pipes which are
in the wrong position.
One of the pipes comes fom the boiler.
If I drain the combi, will it fill up again without airlocks or
something, after I have replumbed the pipes ?

Mike P
Reply to
Mike P
On Sun, 21 Oct 2007 22:48:19 +0100 someone who may be Mike P wrote this:-
No idea.
Hint - it depends on how you do the plumbing and how then person who did the plumbing before you did the plumbing. If both things are done properly then there should be no airlocks, which are a sign of poor design. Pipes should slope gently upwards to somewhere where any trapped air can be released.
Reply to
David Hansen
.. >On Sun, 21 Oct 2007 22:48:19 +0100 someone who may be Mike P .. > wrote this:- .. > .. >>I am removing the kitchen units and have to move two pipes which are .. >>in the wrong position. .. >>One of the pipes comes fom the boiler. .. >>If I drain the combi, will it fill up again without airlocks or .. >>something, after I have replumbed the pipes ? .. > .. >No idea. .. > .. >Hint - it depends on how you do the plumbing and how then person who .. >did the plumbing before you did the plumbing. If both things are .. >done properly then there should be no airlocks, which are a sign of .. >poor design. Pipes should slope gently upwards to somewhere where .. >any trapped air can be released.
I suppose what I mean is ..... will the boiler fill up again without problems before I switch it back on. I am moving the suppply only 30cm to accomodate the new position of the cooker.
Mike P
Reply to
Mike P
Are you talking about the cold water pipe feeding it from the main to produce hot water or the one coming from it carrying the hot water used at the taps? If you are, then the water pressure when you run the taps should clear it. Obviously do that before turning on th boiler
If you mean the pipes that are part of the heating circuit for the radiators then you don't have this. In that case you would have to drain the system and the procedure can be more complicated if the pipe runs are not well organised
Reply to
Andy Hall
On Mon, 22 Oct 2007 08:07:00 +0100 someone who may be Mike P wrote this:-
No idea.
Does the pipe go to the boiler from above or below?
If it goes from above, provided you ensure it slopes gently towards the boiler from its old position any air should escape back into the old pipework and presumably it will be able to escape somewhere else.
If it goes from below, provided it slopes gently up towards the boiler any air in the pipe will escape upwards towards the boiler. What happens next depends on the existing pipework. Is there an air vent anywhere?
A gentle slope means that, the slope should hardly be visible to the naked eye. Vertical runs are not a problem provided they are in the right place.
The aim is to give air somewhere to escape and avoid features where there is nowhere for the air to escape like au upside down U. The "escape place" may be a new air bottle and vent, or back into the existing pipework where it will escape via existing fittings.
Mains pressure pipework has the advantage that the water may force air along to somewhere where it can escape. However, this is not a reason for poor pipework design.
Reply to
David Hansen
On Mon, 22 Oct 2007 08:30:54 +0100, Andy Hall wrote:
.. > .. >> On Mon, 22 Oct 2007 06:13:19 +0100, David Hansen .. >> .. >> .. >On Sun, 21 Oct 2007 22:48:19 +0100 someone who may be Mike P .. >> .. > wrote this:- .. >> .. > .. >> .. >>I am removing the kitchen units and have to move two pipes which are .. >> .. >>in the wrong position. .. >> .. >>One of the pipes comes fom the boiler. .. >> .. >>If I drain the combi, will it fill up again without airlocks or .. >> .. >>something, after I have replumbed the pipes ? .. >> .. > .. >> .. >No idea. .. >> .. > .. >> .. >Hint - it depends on how you do the plumbing and how then person who .. >> .. >did the plumbing before you did the plumbing. If both things are .. >> .. >done properly then there should be no airlocks, which are a sign of .. >> .. >poor design. Pipes should slope gently upwards to somewhere where .. >> .. >any trapped air can be released. .. >> .. >> .. >> I suppose what I mean is ..... will the boiler fill up again without .. >> problems before I switch it back on. .. >> I am moving the suppply only 30cm to accomodate the new position of .. >> the cooker. .. >> .. >> Mike P .. > .. >Are you talking about the cold water pipe feeding it from the main to .. >produce hot water or the one coming from it carrying the hot water used .. >at the taps? If you are, then the water pressure when you run the .. >taps should clear it. .. >Obviously do that before turning on th boiler .. > .. > .. >If you mean the pipes that are part of the heating circuit for the .. >radiators then you don't have this. In that case you would have to .. >drain the system and the procedure can be more complicated if the pipe .. >runs are not well organised
One is the hot domestic water from the combi boiler to the taps and the other is the cold water from the main to the combi boiler. Both have to be moved.
Mike P
Reply to
Mike P
On Mon, 22 Oct 2007 08:30:54 +0100, Andy Hall wrote:
.. > .. >> On Mon, 22 Oct 2007 06:13:19 +0100, David Hansen .. >> .. >> .. >On Sun, 21 Oct 2007 22:48:19 +0100 someone who may be Mike P .. >> .. > wrote this:- .. >> .. > .. >> .. >>I am removing the kitchen units and have to move two pipes which are .. >> .. >>in the wrong position. .. >> .. >>One of the pipes comes fom the boiler. .. >> .. >>If I drain the combi, will it fill up again without airlocks or .. >> .. >>something, after I have replumbed the pipes ? .. >> .. > .. >> .. >No idea. .. >> .. > .. >> .. >Hint - it depends on how you do the plumbing and how then person who .. >> .. >did the plumbing before you did the plumbing. If both things are .. >> .. >done properly then there should be no airlocks, which are a sign of .. >> .. >poor design. Pipes should slope gently upwards to somewhere where .. >> .. >any trapped air can be released. .. >> .. >> .. >> I suppose what I mean is ..... will the boiler fill up again without .. >> problems before I switch it back on. .. >> I am moving the suppply only 30cm to accomodate the new position of .. >> the cooker. .. >> .. >> Mike P .. > .. >Are you talking about the cold water pipe feeding it from the main to .. >produce hot water or the one coming from it carrying the hot water used .. >at the taps? If you are, then the water pressure when you run the .. >taps should clear it. .. >Obviously do that before turning on th boiler .. > .. > .. >If you mean the pipes that are part of the heating circuit for the .. >radiators then you don't have this. In that case you would have to .. >drain the system and the procedure can be more complicated if the pipe .. >runs are not well organised
Not central heating circuit.
Combi boiler. Two pipes.. hot domestic water to the taps and cold water input to the boiler... to move approx 15cm. ..... so no distinctive change of layout.
Then there is the woodworm problem... but that is another thread :-)
Mike P
Reply to
Mike P
Before moving pipe(s) from a boiler it is a very good idea to know exactly what those pipe(s) do.
If you are 100% sure the pipe is a flow or return pipe then SealedCH FAQ should help you a lot.
Reply to
Ed Sirett

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