Vokera 24-96 Flowmatic

[Balj]

This boiler stopped working, kept tripping mcb, turned out pump fault, replaced pump and pcb, cured that problem, but now hot water ok, but rads not heating up. Boiler was firing up and flow leg was heating up, but return stayed cold, changed diaphragm in heating manifold. now back to start and not working again. Could the pcb have blown again, and if so are we missing something that could be causing the fault. Any help appreciated.

 

[picasso]

sure both the flow and return valves are open, did you open the automatic air vent when filling the system , is the pressure at 1 bar and finally if nothing is working now the over heat stat may have tripped, I think on this model its a push button, youll find it on one of the pipes at top of boiler,CAREFUL 240v make sure the boiler is isolated before you stick your fingers in.

 

[Balj]

thanks for speedy feedback, picasso. yes we've done all you've mentioned. when filling system, we also bled boiler of air via nipple. have checked overheat stat and it's not popped out. flow and return valves also definately open, and pressure at 1.5bar. got nasty feeeling it's blowing pcb, but need to find out why. All suggestions appreciated.

 

[DP]

Why did you change the PCB in the first case. Why do you think the PCB is blown now?

 

[Balj]

When the faulty pump was replaced, it didn't fire up and there was a voltage across pins 10 & 30, which according to the vokera flow chart said replace pcb. once pcb replaced it did fire but not circulate round primary cct. wether it was the pump that blew it or something else i don't know.

 

[DP]

Missing voltage across 10 and 30 does not mean the PCB is duff, more likely voltage is missing as sequence has not got to the point when voltage would applied across the said points.

 

[kevplumb]

it didn't fire up and there was a voltage across pins 10 & 30,

come on dan put the bottle down

 

[Balj]

no activity for a while, does this mean you guys haven't a clue, or is it too difficult even for you all. (i've asked for help from vokera, but seeing as they only sell the stuff, they don't want to reply).

 

[DP]

First bit of advice is do not knock the regulars here. They give advice for no rewards, to knock them surely results in a quiet front so you will be on your own.

Clearly from your post it would appear you are pokeing and hopeing to clear a defect (am almost sure it is not a defect). Suggest you look at the manual under commissioning and see what it says.

Missing voltage across 10 and 30 does not mean the PCB is duff, more likely voltage is missing as sequence has not got to the point when voltage would applied across the said points.

Any answer regards above?

When was the boiler serviced last. If it was serviced, what did the service comprise?