Vaillant VCW fault. Help

[jmsjabb]

Any service men out there.
I have a combi LPG bioler which now ignores the feed from the thermostat and timer. IE it is on constantly, unless I switch it off at the bioler.
Is this a circuit board?
I have had the front off and have disconnected the switched live and it still comes on.

 

[kevplumb]

check the servo valve and / or switch ain't stuck on hot water

 

[jmsjabb]

Where would I look for that?
When the rads are turned off on the boiler, the bioler fires when a tap is turned on, ie this seems ok

 

[kevplumb]

ditch my last post then

you didn't mention that