Feed & Expansion Tank Overflowing

Postby Lionel » Wed Dec 30, 2009 1:34 am

I have an old Baxi boiler with a separate hote water cylinder installed in 1992. I presently have a situation where the expansion tank is over-flowing when the system is on & coming out from the overflow pipe.The system loses pressure so I have to adjust it (with a screw driver turning a valve to let in air-between Bar 1 & 2)Otherwise it loses pressure & needle falls to zero.
Last week I had a situation where Br Gas were called in with their one off charge to fix a problem which they said was due to a faulty alternator valve ie when the thermostat indicated the hot water was warm enough the central heating switched off- he said he replaced the valve)
Does anyone have an idea as to where the fault lies in the system?
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Postby Steve the gas » Wed Dec 30, 2009 11:42 am

Sounds like its over-pumping.
Find your pump, if it has speed settings - turn it down and observe any changes.
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Postby rosebery » Wed Dec 30, 2009 5:58 pm

I think some more details about how your system is put together would be a good idea please.

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Postby N Copeland » Thu Feb 18, 2010 10:18 pm

Hello, did you get this problem sorted and if so can you advise waht the cause was? I am having a similar issue, hence the cquestion. Thanks, Neil
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Postby gisago » Mon Feb 22, 2010 9:25 pm

Right, from what i can make out you have a sealed ch system on a standard cylinder (not unvented). I think the coil in the cylinder has a hole in it. Thats where your ch pressure is going. Its going into the cylinder up into your tank and making it overflow. So you need a new cylinder.
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