Which component receives a 24 VAC signal from the controller to operate a zone valve?

• A. The controller output terminal block.
• B. The master valve.
• C. The valve body.
• D. The solenoid on the zone valve.

Answer: (C)

The signal from the controller is designed to energize the valve’s actuator. In a zone valve, that actuator is the solenoid mounted on the valve. When the 24 VAC is applied, the solenoid creates a magnetic force that moves the valve mechanism to open or close. The valve body is just the mechanical housing for the internal parts and the water pathways; it doesn’t respond directly to electrical signals. The controller’s output connections provide the path to the solenoid, but the component that actually receives the electrical signal and converts it into motion is the solenoid on the zone valve. The master valve is a separate valve in the system and not the zone valve’s own actuator.