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Andrew Smith
Andrew Smith, Home Appliance Technician
Category: Appliance
Satisfied Customers: 3756
Experience:  Gas cooker specialist
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Situation Boiler stat turned to off, controller to demand hw

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Situation Boiler stat turned to off, controller to demand hw valve opens, pump turns and then goes off after 45 seconds. Valve resets, pump turns off. On central heating the system continues to run for minutes in this config.
My question I was trying to isolate boiler from problem is the programmer the only item that knows about time and difference between CH and HW - I have checked all external and internal stats and as the boiler is not allowed to fire up (As turned off) it cannot be stat controlled. Should I replace programmer?
***** ***** : Do you have a motorised valve in the airing cupboard?

Yes it is an S system two valves

***** ***** : Can you confirm if everything shuts down because the valve shuts?

I can say that I have checked with a volt metre and can see the HW demand go off and the valve wind back, the pump also stops

***** ***** : Are you checking power to the brown of the motorised valve?

No but can do now

***** ***** : Ok, let's start there and work our way back
***** ***** : If the power is constant there and valve keeps closing then it is a faulty valve

Power is constant and valve just closed


Am I correct in assuming the orang wires are switch returns?

***** ***** : Grey and orange make to fire the pump and boiler
***** ***** : Depending on the valve you can swap the motor, or you may have to swap the whole head

Andrew thank you, ***** ***** the motor a year ago, looks like it has gone intermittent again its a honeywell

***** ***** : No problem, well found

thank you for your time Andrew cheers

***** ***** : If you have nothing further, just lick accept to close the question
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