User Guide

CALIBRATION: SINGLE STAGE THERMOSTATS — TC-202

Adjustments

Dial

The dial setting determines the operating point of the thermostat. It may be locked in place

by tightening the recessed Allen set screw in the top of the dial shaft (see Cut 1 in Figure-9).

Differential

The differential between the two contacts of the SPDT switch is easily adjusted by means of

the differential adjustment screw on the thermostat arm (see Cut 2 in Figure-9). This adjust-

ment screw regulates the distance that the thermostat arm is required to move to trip from

one contact to the other. Adjustable from 1° to 15°. Factory set at 2°.

Calibration Procedure

After differential adjustments in the field, the calibration screw (see Cut 3 in Figure-9) may

be used to re-calibrate the control as follows:

1. Immerse the sensing bulb for about 10 minutes in a medium of known temperature.

2. Turn dial to setting corresponding to bulb temperature.

3. Turning calibrating screw to the right (CW) lowers control point temperature, and turning

to the left (CCW) raises control point temperature. Turn the calibrating screw CW or

CCW as required until the switch clicks.

4. Rotate the calibrating screw in the opposite direction until switch clicks again.

5. Set calibrating screw half way between points where switch clicks. (One full turn of

calibrating screw represents approximately 12°.)

Figure-9 Adjustment of Single Stage Thermostats.

Cut 1 Cut 3Cut 2

Figure-10 Part Identification of Single Stage Thermostats.

Dial

Calibrating Screw

Differential

Thermostat Arm

Dial Screw

Bellows Plunger

Cover Screw

Tension Spring

Plunger Spring

Thermal

Switch Insulator

Terminal Block

Switch

Differential

Element

Spring

Adjustment

Screw