Baxi Solo PFL sYSTEM 60 Expansion Tank - pressure?

[Swin]

Hi all,

I have a Baxi Solo PFL System 60 and I think I may have a problem with the Expansion Vessel. Reasons:

The system has several rads, one of which does not have a TRV and is permanently open, therefore there is always flow round the system. I also have a 'cool down' loop built in.
There is no air in the system.
I can find no leaks in the system.
With the start pressure set to 1 bar, on firing up, over 10 - 15 mins the system runs up to over 3 bar, ie into the red zone. The pressure relief valve then opens sending v hot water down the overflow pipe. It shuts off at around 3 bars and the system runs normally.
When the system cools down (ie overnight) the pressure runs down well below 1 bar - in fact the pressure gauge needle is on the low stop - ie 0 bar. I then re-pressurise to the specified 1 bar and the whole thing happens again.
As the experts will know, the boiler has a red expansion vessel built in at the back rhs. The manual says this should be pressurised to 1 bar. There is what I think is a pressure test tube below the expansion vessel running from Lt to Rt and ending in a car type valve. When I tried to connect a pressure tester to this water came out under pressure.
Questions:
1, obviously, do you think my analysis is correct?
2. Should there be water or air in the expansion vessel (if it should be water, I don't see how it can do anything).
3. If air, is it faulty, and if so what do I do, and
4 If it's not faulty how do I drain it and how do I re-pressurise?
4. If all the above is wrong, how should I proceed?
Thanks,
Swin.

 

[Agile]

I dont remember seeing a system version of the Solo.

However, the EXV should be pressurised with air and yours seems to have failed.

You need to replace it or fit another one elsewhere on the system.

Tony

 

[gas4you]

You are correct.

You need a new ev

 

[Swin]

Thanks both for your replies, and for taking the time to do so. Tony, when you say you don't remember seeing a System version of the Solo, I'm quoting the name of the boiler from the installation manual and casing - is this causing confusion? There's no header tank (fairly obvious I guess) and the EV is built in at the back, behind the combustion chamber. Replacement looks like a complicated job, and will certainly mean demounting the unit (small cupboard). Any guesses as to cost? The unit is seven years old - am I looking at replacement being more sensible, and if so, any recommendations, please?
Thanks again,
Swin.