Vaillant ecotec not switching to hot water

[Whitevanman]

It's an 837 model, about 6 years old. CH works fine but no hot water. Did the following but now need help.

1) Opened up the front to find diverter valve has a leak
2) Stepper motor seemed to work when switching between HW and CH but action seemed poor and thread was in poor condition.
3) Replaced diverter valve (original not available but recommended replacement used)
4) on reconnection I have the same problem. CH but not hot water. I can manually switch to hot water by pulling the diverter pin when motor removed
5) It seems the motor is always driven outwards, even when switching to HW when it should be pulled in
6) wiring to PCB seems OK.

Can only suspect the PCB at this point.

Any help greatly appreciated

Mark

 

[Bunnyman]

Valve leaks to motor and shorts pcb, needs replacing I'm afraid

 

[Whitevanman]

Fitted new PCB which has sorted it. Thanks for the confirmation. Cost of parts was the same as Vaillants fixed price parts and labour call out. You can't win them all but at least I have a better understanding of how my boiler works.

 

[Bunnyman]

Ur welcome i got hammered on another thread for being arrogant, 😄