fault finding

[Hamygray]

Hi I have a vokera 20 80 flowmatic, Could someone please help.
When I turn on the hot water the gas wont light. I have to turn the heating on to get the gas up then turn on the hot water then turn the heating off. The hot water then works perfict. It was lighting sometimes but not evey time.
I thought it could be the micro switch so I replaced it but no luck.

Thanks Graham

 

[Trance Nation]

Last time i encountered a fault very similar to that it was a case of replacing the full "service kit". All parts of it. Turns out it was summit to do with the differential pressure between c'h and h/w. Sumething along those lines anyways - the vokera help desk explained it but i forget now, but i remember it being an odd fault.

Anyhoo - service kit req'd i reckon.

 

[DP]

What is your location and water quality like there?
What is the service history?

 

[corgiman]

DP is right

they are a git for scaling up

yes i know they shouldnt due to temperature but they do and when then do the flow rate is reduced and wont actuate the flow switch

 

[DP]

The Vokera Flowmatic, Turbo and Excel would appear to be the boiler of choice around here. This means I get to see a good number that are malfunctioning. I would say, in majority of cases the malfunction is due to nil service (as prescribed by the makers).