Faulty PRV? (wb 37cdi combi)

[lasors]

Hello all,
My in-laws boiler shut down today, no hot water from taps or CH, error code E9 which is overtemp I think. Pressure gauge is zero, tried refilling but the gauge only shows a slight increase and then the water just flows out of the copper pipe on the outside wall.

Am I right in thinking this is a faulty pressure release valve causing this?

Likely cost of replacement?

Thank you very much for your help.

 

[45yearsagasman]

PRV's don't fail for no reason. The cost will depend on rectifying the fault. It maybe expansion vessel charge low, but it needs investigation.

 

[lasors]

I think the prv was stuck open. I've reset it and it appears to be ok now. I will keep an eye on it and if it happens again I will call someone in. Many thanks