zone Valve Actuator

[pritch]

Hi chaps.
I've got no heating and after a bit of fault finding, I've found there's no switch feed coming from the actuator which then fires the boiler.
The feed side to the actuator is present when you call for heat so couldn't this be linked to send the voltage to fire the boiler and by pass the actuator?
Am I missing something?

 

[Leesparkykent]

When calling for heat the brown is live, motor opens valve which closes the micro switch between grey and orange, when the call for heat is satisfied or turned off the valve spring returns to close the valve and opening the micro switch between grey and orange.

so if you bypassed the micro switch the boiler would keep flogging it's guts regardless off being satisfied or turned off as the grey is a permanent live (not a very clever idea).

what make is the valve?