This water valve replacement is used in every (water cooled) Stoelting soft serve machine. It's purpose is to regulate the discharge, or high side, pressure in your Stoelting frozen yogurt machine.
Replacement Schedule
This water valve is usually replaced because it is leaking, sometimes because is restricted. When the compressor shuts off, the water should stop flowing through the machine within 5 seconds, if the water does not stop you probably have a bad water valve. Restrictions are more common in locations running off of a well or that have "hard" water issues.