vaillant turbomax plus 824e expansion vessel replacement?

[Hackett123]

Good evening, looking for some advise please. My parents have trouble with their boiler leaking out of the PRV due to excessive pressure build up. I have checked the expansion vessel at the rear and sure enough water comes out of the valve when you press it. My guess is this need replacing? can the rear mounted ones be changed or does the whole unit need to come off the wall? Don't wanted my parents being misled if this is a simple job. Thanks in advance

 

[Harry Bloomfield]

My guess is this need replacing? can the rear mounted ones be changed or does the whole unit need to come off the wall?

You could fit an alternative EV, somewhere else in the system, instead.

 

[ianmcd]

Try re-charging the vessel first

 

[Hackett123]

I could but was wondering if the original one could be replaced just for tidiness. I wondered if it was just the main nut and then pull out the top, obviously need to move the flue out of the way first. parents are getting old and one company have already told them £82 just to come out and take a look , plus said probably need to come off, then tried to sell a new one. just looking out for them as was hoping to get it fixed for a couple of hundred pounds not thousands.

 

[Hackett123]

Try re-charging the vessel first

would water come out if it was ok then?

 

[ianmcd]

would water come out if it was ok then?

yep the water coming out means nothing

 

[Hackett123]

You could fit an alternative EV, somewhere else in the system, instead.

I could but was wondering if the original one could be replaced just for tidiness. I wondered if it was just the main nut and then pull out the top, obviously need to move the flue out of the way first. parents are getting old and one company have already told them £82 just to come out and take a look , plus said probably need to come off, then tried to sell a new one. just looking out for them as was hoping to get it fixed for a couple of hundred pounds not thousands.

 

[Hackett123]

yep the water coming out means nothing

that's good news then as i didn't try topping it up thinking it was shot. what is a rough guide for the pressure please and should the boiler be hot or cold. should i make sure the system pressure is 1bar before pumping away? thank you for your help so far.

 

[Johntheo5]

You might consider to keep releasing water via the schrader valve, if diaphragm OK then the water will stop eventually, if not then new EV required IMO. keep a eye on the boiler pressure when bleeding off the water.

 

[Hackett123]

You might consider to keep releasing water via the schrader valve, if diaphragm OK then the water will stop eventually, if not then new EV required IMO. keep a eye on the boiler pressure when bleeding off the water.

okay that's great. I'll give both these a go first and report back.

 

[Hackett123]

You might consider to keep releasing water via the schrader valve, if diaphragm OK then the water will stop eventually, if not then new EV required IMO. keep a eye on the boiler pressure when bleeding off the water.

Hi everyone and thank you for your help so far. Quick update. I drained the boiler down, pumped up the expansion vessel to fully clear the boiler before closing the bleed valve and pressurising to 1 bar. refilled and all looked good. 2 days later parents calle dto say pressure still going up on its own over a 1 day period. Suspected faulty loop fill topping it up as braided pipe is still in situ. Unscrewed the braided pipe and it was leaking from both the tap side and the non return valve end. Replaced the loopfill tap, hose and non return valve. Expansion vessel still ok now and holding 1 bar.
Today, some weeks later, my parent have said it still has the original fault. pressure raising over a 24hour period. only think i'm thinking now is could it be letting by the diverter valve and is there a way of checking this please. can't see how else the boiler can be topping its self up? open to any ideas and thank you in advance.

 

[Johntheo5]

I think the diverter valve only diverts the primary water into the DHW PHE (plate heat exchanger) so its possible that the PHE is leaking water between the primary and secondary sides and pressurising the primary side?.
Maybe worth disconnecting the filling loop at one end to absolutely rule out any leak past.

 

[Johntheo5]

Good evening, looking for some advise please. My parents have trouble with their boiler leaking out of the PRV due to excessive pressure build up. I have checked the expansion vessel at the rear and sure enough water comes out of the valve when you press it. My guess is this need replacing? can the rear mounted ones be changed or does the whole unit need to come off the wall? Don't wanted my parents being misled if this is a simple job. Thanks in advance

Are you sure that you you checked that the EV diaphragm is OK by keeping the schrader valve opened and ensuring ~ 1 bar on the boiler (water) side to push the diaphragm righ up against the schrader valve, if no water then eissues then a reasonable indication the the diaphragm is OK but not foolproof as the diaphragm could be pinholed but as its now sealed against the schrader valve then no water might leak out. I am very skeptical that any water in the air end is simply condensation.

 

[Hackett123]

I think the diverter valve only diverts the primary water into the DHW PHE (plate heat exchanger) so its possible that the PHE is leaking water between the primary and secondary sides and pressurising the primary side?.
Maybe worth disconnecting the filling loop at one end to absolutely rule out any leak past.

Ok thank you. i'll have to pop over there tomorrow and disconnect to check the loop but pretty certain it will be ok. have you ever heard of a PHE leaking across to the other side?

 

[Hackett123]

Are you sure that you you checked that the EV diaphragm is OK by keeping the schrader valve opened and ensuring ~ 1 bar on the boiler (water) side to push the diaphragm righ up against the schrader valve, if no water then eissues then a reasonable indication the the diaphragm is OK but not foolproof as the diaphragm could be pinholed but as its now sealed against the schrader valve then no water might leak out. I am very skeptical that any water in the air end is simply condensation.

No haven't checked the EV like this yet but I will. just wondered if like Johntheo5 said above if it could be the PHE leaking across? obviously the EV needs to be ruled out first.