Ferroli Domina 80E Safety Valve

Hi

I am having a problem with my boiler in that although the filler loop has been disconnected from the cold water, the overflow pipe is letting out water everytime the heating or hot water come on. The pressure gauge is set to 1 bar when cold and hot around 2 bar.

The expansion vessel has been checked and there is no problem there. My engineer is stumped saying it is something to do with the heat exchanger being dual action and insists that if the boiler is letting water out of the system through the overflow pipe it must be getting in somewhere.

I have spoken to a colleague who has suggested it is the safety valve as the same fault occured with his Ferroli. Has anyone had a similar problem?

Thanks for reading.

if you leave the boiler off what does the pressure rise to ?

When the heating and hot water are off the boiler stays at around 1.25 bar.

Thanks.

It isn't an overflow it's a pressure releif valve which shouldn't open below 3 bar. Get a new one fitted. If it gets to 3 bar then you have mains water getting in to the system somehow. Seems unlikely that it should be throughthe heat exchanger as you have only the main one, but...

If I got that far I'dcall ferroli