baxi 105e dropping pressure fault when cold

[seanmfc]

hi to anyone that can help
the above boiler has had over the last 2 years every part changed and i even have a boiler for spares my wifes dad is a plumber but old school so he dont know a lot about combis
over the summer everythings been good hardly any pressure drop now the winters here and the ch is on im having to top the pressure back up everytime its been used its reaching 3 bar and kicking the prv in

has anyone any ideas or is there a plumber that lives near the dartford area to have a look

cheers

 

[45yearsagasman]

Expansion vessel fault, either no pre charge, diaphragm split or communication pipe blocked. Plenty of posts on this, and good advice in the FAQ's.

 

[hertsboilers]

Agree with 45yearsagasman view. Nine out of ten just need to re-pressure the expansion vessel.

 

[seanmfc]

hi
i have done that the baxi book says minimun pressure should be 0.5 bar mine is 0.55 is this ok

thanks

 

[xr4x4]

Afaik you can't top it up with pressure in the heating system, as this will give a false reading.

Did any water come out the valve when you depressed it?

 

[seanmfc]

hi
no water came out of the tyre type valve and the system was drained down prior to checking the ev

 

[xr4x4]

Tried this?

//www.diynot.com/forums/viewtopic.php?p=251090#251090

 

[seanmfc]

its still the same

 

[xr4x4]

Does it only rise when the system is on?

What are you setting the cold static pressure to?

Is this the first time you have had this problem?

Is the filling loop off? Have you disconnected it to confirm this?

 

[seanmfc]

the system works as it should i set the pressure when cold to 0.8 it reaches 3 bar when hot kicks the prv in when the ch goes off the pressure when cold gets to 0.5 bar the filling loop is dissconected and no water passing this has possibly been the problem for at least a year but it was ok on hw only in the summer

 

[hertsboilers]

Don’t need waste any more time on asking I am very positive you need to re-pressure the expansion vessel by a boiler repair man.

 

[xr4x4]

Try turning off the mains stop cock, or better the mains supply to the boiler.

 

[seanmfc]

turning the mains supply off to the boiler did not make any difference will try the ev thing again folling it step by step will report back when i have tried it

 

[xr4x4]

I'd try more pressure in the ev, more like 0.75 bar.

 

[Gees]

When my boiler packed in with this it was the little tube clogged up ( as mentioned in earlier post) A bit of wire unplugged it and no bother since then.I did have a problem getting the EV pumped up but eventually used a foot pump with a long extension tube on it. Worked a treat.