Heating pressure problem

msgj · 3 Jan 2007

Hello, I have two problems with my heating system which have started recently. Not sure if they are related. My boiler is a Baxi Combi 105e.

Firstly the pressure seems to vary tremendously. When the system is cold the pressure often goes below the minimum 0.5 bar. Then the boiler and radiators make gurgling noises when starting up. However if I top up the pressure, when the system gets hot it is going above the maximum and trickling out of the overflow valve.

Secondly the overflow valve seems to be leaking as it is dripping from the boiler instead of going out of the overflow pipe.

By the way I have checked that every radiator is full of water.

Thanks for any advice you may have.

corgiman · 3 Jan 2007

need a new expansion vessel probably

is it the instant version?

msgj · 3 Jan 2007

Yes it is the version that stores some quantity of hot water. So this looks like a call-out job then?

baxpoti · 3 Jan 2007

Alternatively put in an external exp vessel
at least 10lt

Its normally a boiler off the wall job (unless you've got a vertical/side flue)

msgj · 4 Jan 2007

Thanks for your responses. A couple of further questions ...

I have read in other threads about a valve on the expansion vessel which you can use to check the pressure and inflate if necessary. However I cannot find such a thing on my boiler.

baxpoti, will adding an external expansion vessel work with my boiler? Does the hot water storage of this version affect things in any way?

Thanks again. I'm intrigued why this should have failed as my boiler is only three years old.

msgj · 5 Jan 2007

Any chance of a reply on this one?

Does anyone know if the expansion vessel on a 105e instant has a valve that
can be inflated (such as I have read about on other threads)?

And does anyone know if an external expansion vessel can be used with this boiler?

Thanks in advance!

baxpoti · 6 Jan 2007

The schreider valve on the expansion vessel is on the top of the boiler at the back

Remove the 4 screws and supporting bracket

With no system charge this should be around 1 bar

The rest of your questions have already been answered!

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Heating pressure problem

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