Compressor Motor Contactor and Electrical Heater Contactor

evaporator coil. These heaters provide the heat

called for by the temperature control to maintain

the required temperature of the conditioned air.

The two banks of heaters provide two ranges of

heating and are manually controlled by placing

t h e selector switch in the proper position

( L O - H E A T or HI-HEAT) to maintain the re-

quired temperature.

b. Inspection. Inspect

elements

for

breaks,

cracks, or other damage.

c. Removal. Remove electric heater elements as

illustrated in figure 5-10.

d. Installation. Replace a defective heater and

install in reverse order of removal as illustrated in

evaporator to prevent coil freeze up. Valve is

preset to establish a minimum pressure in the

Figure 5-5. Outdoor themostat removal and

evaporator of 57.8 psig.

installation.

b. Adjusting. Adjust the back pressure regu-

and install in reverse order of removal as illus-

lating valve by loosening the lock nut at, the top of

trated on figure 5-9.

the valve and turning the adjusting screw.

Tighten the lock nut after adjustment.

d. Inspection. Inspect terminal blocks for

cracks, breaks, or other damage.

c. Removal. Refer to figure 5-10, and remove

the back pressure regulator valve.

5-15. Compressor Motor Contactor and

Note. Discharge the refrigerant before removing back

Electrical Heater Contactor

pressure valve.

d. Installation. Replace a defective back pres-

a. General. Both Contactors are located in the

sure regulating valve and install in reversing

control box, figure 5-9. A motor contactor starts

order of removal as illustrated on figure 5-10.

the compressor motor and a heater contactor is

Evacuate, and recharge refrigerant system (para

connected to the electrical heaters.

5-33).

b. Removal. Remove contractors as illustrated on

figure 5-9.

5-19. Wiring Harness and Wire Leads

e. Installation. Replace defective Contractors and

install in reverse order of removal as illustrated

a. General. The electrical circuits in the air con-

on figure 5-9.

ditioner are completed by individual wire leads or

by wire leads laced or enclosed in a loom to fom a

5-16. Control Box and Receptacles

wiring harness. All of the wiring carries code

numbers. When testing, repairing or replacing the

a. Removal. Refer to figure 59, and remove the

wiring harness or individual wires, refer to the

control box and receptacles.

practical wiring diagrams, figures 1-4. Inspect all

b. Installation. Replace defective (control box

wiring installations for cracked or frayed insula-

and receptacles and install in reverse order of re-

t i o n material. Pay particular attention to the

moval as illustrated on figure 5-9.

wires passing through holes in the frame or

around sharp edges. Repair or replace defective

Caution: Do not remove control box until the

wiring.

circuit breaker linkage is disconnected.

b. Testing. Test for continuity by disconnecting

5-17. Electric Heater Elements

each end. Touch the test probes of a multimeter to

each end of wire. If continuity is not indicated,

a. General. The two banks of electrical resis-

repair or replace wire.

tance heaters are mounted directly behind the

AGO 20053A