Why do I have hot water but no central heating???

[Riley]

Sounds like it may be getting a constant power so stuck in one position? Are you proficient with a multimeter?

 

[1Steven]

Wonder if it has cable to hot water off? Hate three port valves would ban them!

 

[Not a scooby]

Sounds like it may be getting a constant power so stuck in one position? Are you proficient with a multimeter?

No unfortunately not, think it is time for a professional little bit out of my depth!

 

[joni os]

A common problem at this time of year when people require heating, having not used it during the summer.Your motorized valve includes a micro switch which when closed activates the boiler. If the mechanism is worn any extra resistance built up during the summer months results in micro switch contacts failing to close and the boiler not firing. The manual opening lever on the motorized valve, MV. can be used to open the valve for the heating circuit and will sometimes free up the movement allowing the MV to function correctly. The alternative until MV is replaced:- Remove head, call for hot water and set spindle on valve to send primary flow through radiators.
Leave head with all wires attached. Often when parted from spindle, head will function correctly and call for heat, but spindle must still be set manually according to demand.