baxi 105e rising pressure

[seanmfc]

hi to all that can help on this problem

i have the above boiler and the pvr keeps rising every now and then the dial reads (when cold) to 2-2.5 bar when releasing and putting it back to normal the next day the dial reads empty when looking outside there seems to be a very slow trickle of water from the overflow
my wifes dad was a plumber but in the 70s so he is old skool and not very clued up on combi boilers and in the past we have changed most parts apart from the ev i have done 2 air tests with a tyre guage and the left one as you face it red 0.75 the right one 0.65 and both seemed to be wet

any ideas please

thanks

 

[Rodreguez]

when you say overflow do you mean condensate drain or PRV? also if pressure rises when cold there's got to be something filling the system. if pressure rises a lot wen hot then it could be the expansion vessel is faulty

 

[seanmfc]

thanks for the quick reply the prv drain i mean and nothing is filling the system the filling loop is fine

thanks

 

[Toddyplumb]

Expansion vessel has lost its charge or its diaphragm has split/perished

 

[aggis]

If water trickling out of pr pipe, you need a new prv
Drain down thro' old prv
Pump ex vessel to @ 10-14 psi leaving prv open [ water may come out of pipe]
When at right pressure, fit new prv & fill system to 1.25 bar.

 

[ferret]

if the pressure is rising when cold it must be filling somehow! , if you do chek the expansion vessel it should be pumped to the same pressure as cold fill ie 1bar cold fill pressure 1bar air pressure in vessel.

 

[Rodreguez]

yea defo if filling when cold something has to be filling it. if expansion vessel gone would over pressure with expansion so only wen hot

 

[diesel_ltd]

pressurise your system to between 1-1.5 bar, disconnect and cap your fill loop simples! then you can rule out your fill loop passing ps sometimes you can flick the PRV head a few times to clear a bit of dirt if its still passing and your expansion vessel is holding charge get a new PRV only a few quid

 

[seanmfc]

pressurise your system to between 1-1.5 bar, disconnect and cap your fill loop simples! then you can rule out your fill loop passing ps sometimes you can flick the PRV head a few times to clear a bit of dirt if its still passing and your expansion vessel is holding charge get a new PRV only a few quid

hi

i tried this and no water is passing done the prv and no joy either got to try the ev next

 

[seanmfc]

right just fired the ch up in anger everything topped up & no air in the system after about 10 mins the pressure dropped down to 0 and the bathroom rad was gurgling
any other ideas

thanks

 

[Rodreguez]

try again if keeps dropping u got a leak!

 

[seanmfc]

hi

i cant find any leaks no sign of water anywhere but it is still trickling out of the prv overflow very slowly
when i had the ch on today for 15mins the dial went no further than 2 and after cooling went down to nearly 0

thanks

 

[diesel_ltd]

then you are loosing pressure from prv, the pressure will always rise as your system get warmer you only get a true reading of system pressure when the system is cold

 

[Toddyplumb]

Top it up . Turn on Htg . Sit in front of it . Watch pressure . Do not go anywhere for 10 mins and report back .

 

[tackleburger]

He said in the original post the EV valve was wet. Sounds like new vessel and PRV.