baxi 105e 3 bar pressure problem

[seanmfc]

hi all

i was told i would be back with a problem

about a month ago i was advised the ex vessel (which is charged to 1 bar) was knackered so fitted an external one t into the return pipe everything was running fine until i checked the pressure level then i topped it up to 1 bar then ran the ch watched the needle within 5 mins it was at 3 bar so i presume the prv kicked in looked outside confirmed this anyone any ideas

thanks

 

[oldplumber]

check the new expn vessel is charged to .75 bar when the system pressure is zero first.

 

[Billy Bob Bob]

yep sounds like the new ones flat

 

[Toddyplumb]

Did you top the expansion vessel to 1 bar or the heating system ?
Is your filling loop closed and disconnected ?

 

[ferret]

the vessel should be at the same pressure as you are intending to run the system at ie 1bar system pressure = 1bar vessel pressure ,you need to check it with 0 pressure in system then top up and as toddyplumb says disconnect the fill loop in case its letting by

 

[seanmfc]

sorry for the delay in getting back been away for a week

when fitting the new ev it was pre charged to 1 bar pressure then the water was pressurised to 1 bar also

i have now noticed that the needle does not go past 3 bar pressure when hot and also when cooled down the system stays at just over half bar pressure there are no leaks and the filling loop is not passing water more importantly there is no water comming out of the prv
shall i just leave it alone seeing as there is no leaks and no more loss of pressure

 

[Toddyplumb]

How many rads on the system ? What size exp vessel did you end up getting ?

 

[diesel_ltd]

very good point toddyplumb......

 

[seanmfc]

hi all

a 12l ev and there are 6 rads on the system

 

[Toddyplumb]

Are you sure that expansion vessel is charged . Just run through with us how you checked it