3 Way Diverter Valve

[mini634cah]

I think I have a problem with the Honeywell V4073A Mid Position Valve on my heating system. The CH seems to be heating at all times, even if only HW is selected at the controller. I have removed the powerhead from the valve and there is no rotation of the output shaft on the powerhead regardless of what selection is made at the controller. If I rotate the valve spindle by hand there is a definite clunk in the pipework when rotating anticlockwise. To me the above would indicate a failed powerhead and that would be easy enough to replace, my concern though is that although the valve spindle rotates freely it only seems to rotate about 20 degrees, which does not seem much to select 3 valve output position.
Any help appreciated.

 

[Agile]

Its probably more like 40 degrees!

Thats the normal movement.

Its probably that the motor itself has failed and with a little knowledge it can be replaced as a component.

Tony Glazier

 

[mini634cah]

Thanks Tony,
I'll try replacing the motor first, it looks reasonably straightforward.
Can you confirm which direction to manually rotate the valve spindle to set to HW only in the interim ?.
Thanks again
David.

 

[MANDATE]

When HW only is selected power to both the white and grey wires is cut off.
Power on white wire moves valve to mid point while power on grey moves valve from mid point to CH.
If CH is still operating it sounds as though the actuator head is stuck in the CH position. The motor is supposed to unwind by use of the return spring.
Try using the lever to test if the motor is in the unwound position.There should be some resistance as you wind the motor forward.