Taco Safety Zone Valve 'Clicking' - Seeking Assistance

[Synoptic12]

I'm seeking some assistance with a Taco Zone Safety Valve 'clicking' when shutting down. The heat is working fine but the 'clicking' is most annoying. What would the problem be? Some have said it is the motor in the actuator (ZA024Q4A2) part number which is the actuator or head. In replacing this part, would that solve the problem? I would not wish to purchase the part, then find the cause is something else. Here are some pictures and a video clip denoting the 'clicking'. All replies are very much appreciated.
Link: https://vimeo.com/manage/videos/898193384

 

[Fitter30]

Think your actuator has button to push with power off for a manual over ride. By turning the knob and pushing the button. The actuator is bad but see if the valve turns freely compared to another one before just buying one.

 

[Sponsor]

 

[John Gayewski]

In other news your boiler is piped wrong. You have to protection from cold return water.

 

[Fitter30]

Take a few more pic of the piping, ex tank right side of boiler.