RELAYS.-Continued - TM-5-4120-383-140130

TM5-4120-383-14

4-29.

RELAYS.-Continued

Disconnect input power from the air conditioner

before performing maintenance on any part of the

electrical system.

The voltages used can be lethal.

Test.

(1) Disconnect power at power source.

(2) See paragraph 4-21a and remove control module.

(3) Remove top front cover (para 4-11).

(4) Remove seven screws and lock washers and carefully slide

junction box out of unit.

(5) Relays K2 and K3.

(a) Apply 28VDC to terminals X1 and X2; X1 is positive, X2

is negative.

(b) Check continuity across terminals A1 and A2; B1 and B2,

and C1 and C2.

The multimeter must show that contacts are closed.

Multimeter must show that contacts are

open.

(6) Relay K4.

(a) Apply 28VDC to terminals 2 and 9; 2 is positive, 9 is

negative.

(b) Check continuity across terminals, 1 and 3; 5 and 11;

and 10 and 8.

It should indicate that terminals 1

and 3, 5 and 11, and 10 and 8 are closed.

Terminals 1 and 4, 5 and

6, and 10 and 7 are open.

(d) Remove 28VDC power. Multimeter should indicate that

terminals 1 and 4, 5 and 6, and 10 and 7 are closed and that

terminals 1 and 3, 5 and 11, and 10 and 8 are open.

(7) Time delay relay K1.

(a) Connect multimeter to terminal A1 and A2 of relay K3.

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