INSTALLATION CONT.
IMPORTANT
When control is located where ambient temperature is below freezing, choose a control location far enough away from doors and windows so that moisture will not condense on control.
If the thermostat is used with unit coolers, the following suggestions may help. (See Fig. 2).
1.Position “A” is good if it is sufficiently close to the unit cooler so that the return air to the cooler flows over the thermostat.
2.Position “B” is good if it is not necessary to make frequent adjustments of the dial setting.
3.Position “C” is all right if it is sufficiently far from the cooler that air flowing over the thermostat is not much above the average room temperature.
4.In general, position “D” is not advisable because the post may prevent air from circulating over the thermo- stat.
WIRING
| CEILING |
|
| POST | PARTITION |
|
| WALL OR POST |
| UNIT | DIRECTLY |
| BEHIND UNIT | |
|
| |
|
| B |
D | C | A |
| RETURN AIR |
|
FLOOR
Figure 2
All wiring should be done in accordance with local and national electrical codes and ordinances.
If the manufacturer of the cooling equipment has supplied a wiring diagram, follow the manufacturer’s recommenda- tions. The following diagrams show the general use of these controls.
TEMPERATURE
CONTROL
TO LINE SWITCH | HOT |
AND POWER SUPPLY | GND |
|
HIGH SIDE
PRESSURE CONTROL
(IF USED)
Circuit showing temperature control con- trolling compressor directly.
TO LINE SWITCH
AND POWER SUPPLYTEMPERATURE CONTROL
Circuit showing temperature control to open and close refrigerant valve. Suction pressure control starts and stops compressor through motor starter.
MOTOR
STARTER
HIGH SIDE | SUCTION | SOLENOID | |
REFRIGERANT | |||
PRESSURE | PRESSURE | ||
CONTROL | CONTROL | VALVE | |
|
SETTING THE DIAL
To set the dial, simply move it so that the indicating line on the case points to the temperature at which the contacts are to open as the temperature drops.
INDICATING
LINE
70
60
80
2
