Potterton Combi Boiler loosing preassure

[motogod]

I have a peculiar problem with my Potterton Combi Boiler (Potterton 28). The system looses preassure, when cold the gauge shows 0 Bar !! .. but when running it is about 2 - 2.5 Bar !!
The Boiler does not seem to cut off even at 0 Bar when it's cold !!
It did have a minor leak about 2 months ago which was fixed and there are no more leaks now.
The tempreature gauge (on the boiler) show that the water temp of 80 - 80+, I am not sure what is happenning. I called a local engineer he suggested a leak and injected Leak Sealer into the system but it still has the same problem.

 

[mrbriggs]

Sounds like you have the same problem as me, Expansion vessel. Press the "tyre like valve", if water comes out, u need a new one. in the process of sorting mine out too! What is happening, is the pressure is getting 2.5 bar and the pressure relief valve is opening (to stop the boiler over pressurising and going bang!) and that's where the water is leaking from (outside pipe)

Hope this helps!

 

[motogod]

thanks i shall have a look ...