Combi boiler pressure overflow leaking

[mickybannon]

Boiler Ravenheat combi rsf 820/20
Fitted 1998
3 storey house 10 rads. No rad leaks

For a while my boiler was going>3bar when CH on and then pressure was below 1bar when cold due to leakage outside via safety relief valve. Managed for a month with topping up water but after help from this excellent forum realised Expansion vessel probably needed repressurising. Checked today and indeed no pressure in EV, pumped up to exactly 1bar (could have done with a few extra elbows on my arms to manage it though) refilled the system, bled everything, heating working, pressure 1.5bar cold hardly goes up now.

So there I was feeling smug but went outside and the oveflow (pressure relief pipe) still dripping, albeit less than before despite the pressure being 1.5 bar.
Does this mean I need a new safety relief valve or any other possible diagnoses.

If it is this valve am I legally allowed to do this myself? At least this time it is something that is easily accessible.

Thanks in anticipation of any advice.

michael

 

[Paul Barker]

Firstly, Get system hot then turn off boiler and hold open prv to let out a gusher. Sometimes that cleans the seat.

Secondly, drain down undo the black and red plastic part first on it's own. Clean the seat, both parts with very fine emery, reassemble see if that works.

Thirdly, obtain a new PRV

Yes fit it youself, you may find a Canadian Basin Wrench helps.

 

[Agile]

And yes you can legally change it yourself.

Those older people here will possibly remember that when pressurised systems were introduced about 1980 there were discussions and suggestions that a special qualification was required to deal with them. That went nowhere and anybody deals with them now!

Tony

 

[mickybannon]

Thanks Paul for such a quick and helpful reply.

Tried option 1 so far, unfortunately leaking more so will be step 2 +/-3 next week!

I'd better move quickly or the wife will think I've broken it

Michael

 

[mickybannon]

Thanks Tony as well for that!

Michael