Baxi Combi Instant 80 HE Pressure Relief Valve

[ribw]

This is my first posting, so apologies if I don't get it spot on!

My primary circuit pressure is reducing to 0bar because, I believe, the prv is passing water. A steady flow is visible from the pipe outside the house every time I try to recharge the system.
Factors:
Last night was the coldest we have had for a long time.
The boiler is 6 years old.
Last year another boiler part leaked (but it was only detected after the plumber had me rip up all my flooring to look for leaks.)

The prv has a red plastic cover (not tight fitting) labelled with 3 bar and a directional arrow. The cover will only rotate one way (in the direction of the arrow). I can find no instructions in either the operator manual or the install & service manual to indicate what turning the knob achieves.

My main questions is :-
Can I do anything immediately to recover pressure

But also:-
What happens if I rotate the red cover/knob.
Is valve replacement a diy job

Thanks in advance
Bob

 

[ianmcd]

Rotating the red cover opens up the pressure releif valve, the valve is spring loaded onto a diaphragm and the system water pressure pushes against it , if the system water pressure reaches 3 Bar it pushes the valve off its seat and lets the water release to outside in order to protect the appliance from over pressurising, dont keep turning it you will knacker it, if it is constantly leaking and the boiler pressure is no where near 3 Bar then it probably need replacing not too hard a job and nothing to stop you doing it yourself if you want to

 

[ribw]

Thank you for that helpful advice. I will dismantle the prv tomorrow and take it (for matching!) to nearby plumber's stockist or B&Q . [Our road is not safe for 2 wheel drive at the moment so it will be a bit of a hike]. In the meantime, I'll try a few taps with a small hammer in situ.

Thanks again
Bob