Alpha cd 24 c pressure rising

[rab250]

just want to pick your brains about this boiler.
when the boiler is not in operation the pressure rises i have disconnected the filling loop. the only other things i can think of that connects the mains inlet to the central heating are the diverter valve and the plate 2 plate but i am thinking that you would have to run the combi for the pressure to rise if the plate to plate is fractured. does anyone agree or do they have another solution i would like to fix this 1st time without throwing parts at it. any suggestions would be really appreciated.

 

[spikewt]

Probably secondary heat exchanger without looking? dont hold me to it tho!

 

[rab250]

yes that was my original thought but i seem to have talked myself out of it.

 

[spikewt]

Could be ya diverter valve tho. how olds the boiler? does you heating and hotwater work ok?

 

[rab250]

she had boiler fit about 4 yrs ago, everything works fine. i went out to it earlier this week because they complained about high pressure on the gauge. i checked the expansion vessel which was ok and just left it in dhw mode asked them to keep an eye on it and see what was happening as the pressure needle was slightly wobbling when running the dhw ( which made me think the plate 2 plate was at fault). today i called them to see how it was going and they told me they drained it off back to the normal pressure this morning and when they got back from work it had risen upto to about 2 1/2 bar

 

[Puddle]

If it was the seal on the diverter valve,it would be visibly leaking underneath between heating side and mains there are two seals with open /unsealed area in between,it does point to plate heat exchanger

imho

 

[rab250]

cheers puddle , could you just put it straight in my mind how the pressure would rise even when the boiler hasnt been in operation all day . this is the thing that made me change my original diagnosis

 

[Puddle]

It does matter if boiler on or not,cold mains is always connected and present in the plate heat exchanger then on to the hot taps,as is the heating system side always present in the plate,so the one with the higher pressure will always be able to leak through to the other,boiler on or not

 

[rab250]

Thankyou very much that makes perfect sense. I do seem to overthink things and question myself .

 

[Billy Bob Bob]

It does matter if boiler on or not,cold mains is always connected and present in the plate heat exchanger then on to the hot taps,as is the heating system side always present in the plate,so the one with the higher pressure will always be able to leak through to the other,boiler on or not

ditto my sentiments exactly puddle has a knack of getting there first its a mod thing

 

[Puddle]

ditto my sentiments exactly puddle has a knack of getting there first its a mod thing

Sorry

Seem to remember you posted a day before me in the jokes thread but being only a day behind is usually good for me

 

[Billy Bob Bob]

Sorry

Seem to remember you posted a day before me in the jokes thread but being only a day behind is usually good for me

you know i am just kidding great advice as usual puddle