Crappy Vokera boiler pressure loss puzzle

[Burkeyboy]

Hi all. New to this forum, so be gentle with me. I've got a Sabre (rebranded vokera I believe) boiler with an ongoing problem.

When the heating is on, the pressure holds fine, when it's off the pressure drops, the red light of death comes on and I have to reset and top up via the loop. My plumber mate has replaced the PRV for me and the problem is still the same. The boilers about 7 years old so I know it's not got long left, but if it can be fixed rather than replaced.....then it's a bonus.

Oh, and I have checked everywhere for leaks...and nothing!

Any suggestions....? My plumber friends puzzled and my next step is to contemplate changing the expansion vessel. Cheers.

 

[Puddle]

if leaking out of prv,then just replacing will not necessarily correct the problem,why did he not re prime expansion vessel at the time,can you put a plastic bottle over pr pipe outside and see if any discharge


The pressure may not be holding when heating on,just system expansion pressure replacing lost pressure from system,then cools and shows real pressure loss

imho

 

[Burkeyboy]

Thanks Puddle. I'll pop a bag on the bag and see what happens.

 

[Burkeyboy]

Or on the pipe even...

 

[Burkeyboy]

Put a placky bag over the PR for a few hours with the heating off. Only a tiny amount of water in the bag....but it seems to be a lot more inflated with gas than when first fitted. Any further suggestions?

 

[Puddle]

bag should only be fitted loose on pr pipe,leave on and see what happens when heating running

 

[Nas]

Vokeras are prone to gettting the flexi pipe going to the expansion vessel blocked. Put you hand on it with the heating on. If its cold then its blocked.
I think the sabre will have a similar flexi pipe