Question about Honeywell Programmable Thermostat Heater

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No hot water honeywell st6400c

I have a honeywell st6400c when HW is switched on I have no HW lights work but cant hear system kicking in and boiler won't start but if I put heating on boiler kicks in and i get HW and heating? Checked wires as I had a similar problem before with a wire that came loose but no luck...any suggetions

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HW valve was stuck in the open posiion and the micro-switch was not working so thats why boiler and pump were not starting. Bled system to below the level of the valve to be changed, and replaced valve with a drayton ( easy quick change of valve head if needed no screws )

Posted on Sep 17, 2008

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