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.
Any help appreciated.