Product Overview

CHECKOUT

After the entire system has been installed, the following checks for proper operation must be

made.

1. Be sure that the system power is connected, and on.

2. Turn thermostat to call for cool. Actuator should rotate clockwise from 0° to 180°, turning off

the heating media. (View actuator from output shaft end (front).)

3. Turn thermostat to call for heat. Actuator should rotate clockwise from 180° to 360° (also 0°),

and turn on heating media.

4. If the room temperature varies excessively, see System Repair.

Actuator Checkout Turn power off and connect terminals as follows:

1. Connect terminal C to B and actuator should run clockwise (when energized) to end of travel

(usually 180°).

2. Connect terminal C to R and actuator should run clockwise (when energized) from 180° to

360° (0°).

RUN/ADJUST

Theory of

Operation

Unidirectional

Three-Wire,

Two-Position

Actuators

The motor, gear-train assembly with limit switches to stop the movement (usually at the end of

180° CW travel) is built in two types. The damper actuator output shaft gives rotary motion. The

valve actuator has a cam-operated plunger which transforms rotary motion to linear motion to

operate the valve stem. Three-wire actuators require a SPDT switching action in the controller.

“R” contact of the thermostat is made on a call for heat; “B” contact is made on a call for less heat;

“C” terminal is common. “R” of the actuator (assume on valve) is a starting switch that starts to

open the valve; “B” starts to close the valve; and “C” is the limit switch. Auxiliary cam-operated

switches are available for the operation of additional valves, actuators, relays, etc.

Figure-6 Internal Wiring Diagram and Cam Chart.