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Central Heating

Combi boiler keeps losing pressure on boiler

Hi, can anyone tell me why my combo boiler loses pressure when it's been turned off ? When I go to turn it back on in the morning the needle is back to zero. I keep filling it up but the same happens again. I have noticed water drippiing from the overflow pipe outside. Thanks

3 Answers from MyBuilder Heating Engineers

Best Answer

The prv is letting by, you need to call an engineer to take a look


Answered 25th Feb 2015

There is probably a fault with the expansion vessel it has either lost its charged pressure or the internals have perished and it has filled with water. Once that is sorted it may be worth putting on a new pressure relief vave as well as if any debris is imbedded in the rubber of the valve it will not close properly.


Answered 25th Feb 2015

The pressure relief valve is leaking , this is spring loaded and can sometimes be stopped by turning the coloured knob on top until water runs and letting it close violently/fast. You will need boiler off and then re-pressurise system on completion.


Answered 1st Mar 2015

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