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Central Heating

Vessel repressuring


I've had a problem with my baxi combi 80e losing pressure so I called out a heating engineer and he said it was the expansion vessel

He pumped it up whilst the boiler was running and used a bike pump???

He also changed the prv

He said it was ok to do this but I'm sure it's wrong...boiler should be off with no pressure ?

Still getting problems ...prv passed again, when not in use the boiler holds its pressure, phoned him and he said i need a new vessel...he could change the internal one without taking it off the wall all he has to do is disconnect the flue

still waiting to hear from him...nearly two weeks later :(

3 Answers from MyBuilder Heating Engineers

Best Answer

Hi, You are correct, boiler should have been turned off, pressure reduced to zero then the expansion vessell repressurised to app 1 bar. To tell if expansion vessell is no good, pump it up with a foot pump and if you hear a gurgling noise then the air bag is split, if the air bag holds pressure the the expansion vessell is ok, i would then see if problem persists, if it does check pipework to vessel isnt blocked.
Hope this helps.


Answered 27th Dec 2012

You will need a new vessel and prv. the old vessel would have been filled with water as the unit would have been perished. He should have known this. Fit an external vessel and leave the old unit in place, it will be cheaper and better in the long run.
The reason you will need to replace the prv is because they only ever leak a bit once they have been set off.


Answered 27th Dec 2012

I would Ask him why did you pump it up running ? Boiler should be drained when you re-charge a expansion vessel


Answered 10th Feb 2013

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