Powermax Pressure

[briar]

Hi - I am having a nightmare! My Powermax 155x loses pressure all the time! Absolutely everything has been checked a million times - the boiler in working fine apparently and we have no leaks! Any ideas? Could this be anything to do with living in a flat?? i.e bad water pressure generally?
We regularly top it up to about 1.5-2.0 bar and then in gradually drops over a week or so to 0. We have to top it up about every 10 days.
So many people have looked at it and they all maintain it is fine. Is this just a feature that I am going to have to live with?

 

[gazthepottertonengineer]

is water going out the overflow at any time
have they checked the expansion vessell pressure
it has nothing to do with poor water mains pressure whatsoever
i have had a few of these recently where it has been down to a pin hole in the secondary hot water plate heat exchanger and what happens if it is that is when you run a bath for a long while you can actually see the pressure going down on the gauge

 

[briar]

Yes water does go out of the overflow - I am guessing this is the pipe that comes out of the wall outside the property. A potterton engineer told we this is normal though? Do you know different? Water appears to come out of other peoples on my apartment block too
The expansion vessell pressure has been checked like everything else a million times and was even replaced once just in case it was faulty.
The plate heat exchanger has also been replaced I am sure!

What basically happens is the pressure is say at 1.5 bar. Someone then has a shower and the boiler fires up however after the shower the pressure may only be at 1.4 bar. This continues until the pressure gets to about 0.8 and then drops to 0 and lockout.

 

[Baxi-Remeha]

when they changed the expansion vessel, did they replace the prv, as this will probably continue to leak once its been opened....

 

[gazthepottertonengineer]

if water is going out the overflow then theres your problem thats where the pressure is going Its not nornal and i cant believe an engineer told you it was as jase said get the pressure relief valve replaced and hte expansion vessel tested again as theres not alot else it can be