CH Losing Pressure

My CH combi-boiler is constantly losing water pressure, at up to 1 bar every couple of hours.
I can't find any obvious leaks and there's nothing from the overflow/discharge pipe.
Would I notice a leak of this size as a damp patch on a floor or ceiling? Is there anywhere else it could be disappearing to? All pipework is above the ground floor.
Thanks,
--
Bartc


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every
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It could be leaking into the boiler itself. If any pipework is passing through a cavity wall or behind dry lining plasterboard, the leak may be running through to under the house.
Is there a lot of steam coming from the boiler when it starts?
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I haven't noticed any steam although I've only been next to it as I've been filling up when there would be signs of life.
Or do you mean from the exhaust pipe? I probably wouldn't be able to tell whether there was an unusual amount of steam.
The boiler is newish and is upstairs in a converted bungalow and from what I can see the pipes are mostly in the ground floor ceiling, and run down the nearest corner to each radiator downstairs.
(The house is rented and ultimately the boiler is not my responsibility, but it would be nice to pinpoint the problem first.)
--
Bartc


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If it's a condensing boiler and the heat exchanger is leaking, it could be running away unnoticed with the condensate down the drain. If it's not a condensing boiler, such a leak will normally end up running out of the boiler casing as their combustion chambers chambers are not normally sealed completely water-tight.
Does it only lose pressure when the system is operating and hot, or does it also lose pressure when the boiler is not being used? Does the pressure go right to zero if not repressurised, or does it just drop to a certain level and stay there?
--
Andrew Gabriel
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writes:

I'd have to do an overnight test to answer that. I'd say it loses pressure even when off, but:
I don't remember seeing the pressure guage below about 0.4bar, and as it happens the minimum operating pressure is 0.4bar, according to the manual I've just downloaded.
The boiler is an Optima 701 (a combi) and haven't noticed water anywhere nearby.
--
Bartc


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On Thu, 20 Nov 2008 22:25:42 +0000, Bartc wrote:

You should be able to find evidence -somewhere- for a leak of that size.
--
Ed Sirett - Property maintainer and registered gas fitter.
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