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Replace external expansion vessel

Postby Kinstowan » Wed Aug 15, 2007 12:12 pm

My combination boiler drops pressure. I have been told that another expansion tank, fitted externally next to the boiler, will do the job. I am OK with the water side of plumbing but would like some advice on how to do this please.
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Simply Build It

Postby htg engineer » Wed Aug 15, 2007 7:33 pm

The new pressure vessel needs to be tee'd into the return pipe of the boiler with 22mm pipe. The tee has to be as close to the boiler as possible, hope this helps
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Postby AndyB » Wed Aug 15, 2007 10:31 pm

You could check first to see if internal expansion vessel has lost its charge.Recharging might solve the problem
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Postby johnb » Thu Aug 16, 2007 5:08 pm

hi kinstowan if you have pressure drop on boiler then you have a leak in the system or pressure vessel, adding another p/vessel in addition to existing should not be needed if the system has worked in the past.
check existing p/vessel is not full of water on the gas side it has schrader valve on gas side if you depress this and water comes out its knackered. if air comes out it may need recharging recharge to 1/2 bar all the best john
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