The pressure in the combi boiler steadily rises, over about 8 hrs, to 3.0 bar. I've had to keep on bleeding to bring the pressure back down. This happens even with the CH function switched off. I've checked that the filler loop is completely disconnected. I've also switched off, reduced the pressure right down and tried to repressurise the expansion vessel (this seems to slow it down but after a while it starts again). I can only get about 0.75 ish bar in the expansion vessel. Why is this happening with the CH switched off? It's been recommended that the expansion vessel is kaput. Any ideas on what else I can try?
vokera linea 28 pressure rising
- Thread starter DCMc
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if it does it with the heating switched off then its the plate heat exchanger passing mains water to the heating side.
not difficult to change, drain down both sides, two screws to remove and 4 o-rings to change when the new one is screwed on.
also, are you filling the expansion vessel properly? check the FAQ's for the correct way to do it.
not difficult to change, drain down both sides, two screws to remove and 4 o-rings to change when the new one is screwed on.
also, are you filling the expansion vessel properly? check the FAQ's for the correct way to do it.
nothing wrong with it
as above try the h ex
put pressure to 1.5
turn off cold main to boiler
does it stop rising
heat ex
turn off cold main to boiler
does it stop rising
heat ex
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Tried a few of your tips and looked at the FAQs from the site. Released the pressure using the PRV to 1.5 bar, the pressure didn't rise. Tried hot water only, then central heating and everything seemed to work ok and has been since Friday (stays at 1.5 - 2 bar). Could the PRV have been sticking and letting the pressure build up? There was an occasional weep from the overflow outside but that's stopped. I don't want to muck around anymore if it's working. Thanks for your help.
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prv is supposed to stay closed. it should only open at around 3 bar. if it opens at any other time its faulty.
you seem to have given us poor info by saying that that pressure rose when the heating was off, this led us (well me anyway) into suggesting the PHE was passing.
leave it be and see how it goes. if the pressure continues to rise when heating check the vessel pressure. if it does it when the boiler is off then the PHE is the only culprit.
the PRV may or may not be ok, sometimes reseating it will clear the crud off the seat and allow it to keep a seal, other times not.
you seem to have given us poor info by saying that that pressure rose when the heating was off, this led us (well me anyway) into suggesting the PHE was passing.
leave it be and see how it goes. if the pressure continues to rise when heating check the vessel pressure. if it does it when the boiler is off then the PHE is the only culprit.
the PRV may or may not be ok, sometimes reseating it will clear the crud off the seat and allow it to keep a seal, other times not.
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