Boiler losing pressure

[Gifford]

Hi, my grant vortex combi 36 has recently started losing pressure and needs topped up regularly.
After reading some forums I decided to check the PRV. so turned this and the pressure dropped to zero. I did notice that a small amount of water was coming from one of the AAV's.
The pressure still drops but not as fast, but still drops to under 0.5. I have now noticed that there is water coming out of the overflow pipe outside . . . Any suggestions? A colleague has mentioned possible fault expansion on PRV
THANKS IN ADVANCE!!

 

[Gifford]

I meant faulty expansion vessel or faulty PRV

 

[IDCHAPPY]

You've probably got grit stuck in the seat of the PRV when you opened it, the expansion vessel is easy to spot, if your system pressure rockets up to 3bar during the heating cycle and there is more water coming out the prv pipe outside then it's the expansion vessel.

 

[WHPES]

Can sometimes be a blockage in the pipe between the expansion vessel and the boiler. Best to call an expert.

 

[Bunker]

The AAVs always leak on Grants.
The PRV will be shot, either rusted up, grooved seat or rubber will be stiff.
The expansion vessel might not big enough for the house, the 36kw only has a 12l tin, thats good for 120l of water.
Get an OFTEC man out

 

[Gifford]

Thanks to all for help/advice

 

[Soggy]

Probably need a powerflush too, after the faults have been fixed.