mid position valve faulty?

[micktamas]

Hi
Hope someone out there will be able to help.I Recently fitted a Honeywell Y plan pack with ST9400 programmer and V4073A mid position valve. HW and CH work fine independently the problem is when they are both on together, when HW is satisfied from cyl stat it also knocks the CH off even though this is still calling for heat from the room stat. I have checked wiring and that is ok, I have checked the voltages across the grey white orange wires when i get this problem and I am getting 240v on white 240v on grey but nothing on orange, am I right in thinking that the orange needs to be 240v to switch on the boiler if so could it be a faulty switch within the valve head or could it be something else?

 

[45yearsagasman]

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It does seem like your valve head may be at fault.

 

[Madrab]

View media item 30560
It does seem like your valve head may be at fault.

+1 but check it back to the connector box as well to confirm

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[micktamas]

Hi thanks both for your input, at first it does sound like the valve but someone has told me it could be the programmer as this model is notorious for faults, I have done a bit of research and alot of similar problems relate to it, I will get this replaced first as its all still under warranty, thanks and i'll keep you posted