Circuit Breaker - TM-5-4120-274-150048

TM5-4120-274-15

c. Installation. Refer to figure 3-12 and install

3-38. Rectifier

transformer.

a. General. The rectifier changes alternating

current to direct current.

3-35. Circuit Breaker

b. Removal. Refer to figure 3-12 and remove

a. General. The circuit breaker protects the

rectifier.

compressor from continuous overcurrent and

c. Inspection and Testing.

short circuits. It is located in the lower right cor-

(1) Inspect for crackd or broken casing and

ner of the junction box. Refer to figure 2-2 for

burned or damaged contacts.

reset procedure.

(2) Test for continuity with multimeter set

b. Removal. Refer to figure 3-12 and remove

on OHMS. Refer to wiring diagram figure 1-5

the circuit breaker.

to establish points of continuity.

d. Installation. Refer to figure 3-12 and install

c. Testing. Refer to figure 3-12 and tag and

rectifier.

disconnect the leads and teat the circuit breaker

for continuity with a multimeter set on OHMS.

3-39. Heater Elements

Refer to the wiring diagram figure 15 for points

to establish continuity.

a. General. The electrical resistance heaters are

mounted directly behind the evaporator coil. These

d. Installation. Refer to figure 3-12 and install

heaters provide the heat called for by the thermo-

circuit breaker.

stat to maintain the required temperature of the

conditioned air. The heaters provide two ranges

3-36. Phase Sequence Relay

of heating and are manually controlled by placing

a. General. The phase sequence relay prevents

the selector switch in the proper position (LO-

operation of the unit unless the phase sequence

HEAT or HI-HEAT) to maintain the required

is correct and the fan and compressor motors ro-

temperature.

tate in the proper direction.

b. Removal. Refer to figure 3-10, 3-11 and re-

move the heater elements.

Note. Used only on 3 phase units, CV-9-3-08-60 and

c. Inspection and Testing.

CV-9-3-08-400.

(1) Inspect for broken or damaged ele-

b. Removal. Refer to figure 3-12 and remove

ments.

phase sequence relay.

(2) Test for continuity across elements with

c. Inspection and Testing.

multimeter set on OHMS. Refer to wiring diagram

(1) Inspect for cracked or broken casing.

figure 1-5 to establish points of continuity.

(2) Test for continuity with multimeter set

on OHMS. Refer to wiring diagram figure 1-5

d. Installation. Refer to figure 3-10, 3-11 and

to establish points of continuity.

install heating elements.

d. installation. Refer to figure 3-12 and in-

3-40 High Pressure Switch

stall the phase sequence relay.

a. General. The high pressure switch prevents

3-37. Compressor Motor Relay and

the compressor from operating if the head pres-

Electrical Heater Relay

sure exceeds 445 psig (pounds per square inch

gage) (fig. 3-13).

a. General. Both relays are located in the junc-

tion box figure 3-12. A motor relay starts the

b. lnspection and Testing.

compressor motor and a heater relay is connected

(1) Inspect for broken or damaged leads

to the electrical heaters.

and kinked or broken capillary tubing.

b. Removal. Refer to figure 312 and remove

(2) Test for continuity across switch with

relays.

multimeter set on OHMS. Refer to wiring dia-

c. Inspection and Testing.

gram figure 1-5 to establish points of continuity.

(1) Inspect for pitted or burned contacts.

3-41 Lo Pressure Switch

(2) Test for continuity across coil with mul-

timeter set on OHMS. Refer to wiring diagram

a. General. The low pressure switch prevents

figure 1-5 to establish points of continuity.

the compressor from operating if the suction pres-

d. Installation. Refer to figure 3-12 and install

sure drops below 25 psig (pounds per square inch

relays.

gage)j (fig. 3-13).

3-16