Valve head Micro Switch

[RidleyRumpus]

When the valve rotates the cam/cog arm should make contact with the microswitch.

Should this contact be a momentary thing or should the microswitch be permanently engaged in order to fire up the boiler?

 

[picasso]

The sycron motor holds the switch closed , when the call for heat is finished a spring pulls the motor and the switch is opened.

 

[RidleyRumpus]

Thanks, thought so.

 

[stem]

This is true for a two port valve. But, in case you have a 3 Port valve, (you don't specify which you have) there are two microswitches, and under certain conditions one of them will momentarily be operated as the "cam" passes it by. It's not the one that operates the boiler though.