A synchronous motor is an AC (alternating current) motor that runs at a speed directly proportional to the frequency of the AC power supply. When power is applied to the zone valve, the synchron motor moves the ball inside the valve allowing the flow of water to a particular zone or area. When the area has reached temperature, the power to the synchron motor is cut and the closes the valve, shutting off the supply.
Fits into most brands of zone valve Reinforced gear pin 230v AC 50Hz 5RPM