TM 9-4110-258-13
4.28 CONTROL RELAYS K3 AND K4 TESTING AND REPLACEMENT.
This task covers:
a. Testing
b. Removal
c. Installation
INITIAL SETUP
Tools:
Equipment Conditions:
Heat Gun
Refrigeration unit shut down (para 2.7) and power
3, Section III, Appendix B
disconnected.
Control box cover door raised and latched.
Materials/Parts:
General Safety Instructions
Lock Washer (1) (K3)
6, Appendix G
WARNING
Lock Washer (1) (K4)
6, Appendix G
Sleeving Insulation (3) (K3)
High voltage and exposed rotating parts are
used in the refrigeration unit. Personal injury
Sleeving Insulation (2) (K4)
can result if power is connected.
Marker Tags (4) (K3)
7, Appendix E
Marker Tags (6) (K3)
7, Appendix E
a.
Testing. (See Figure 1-4.)
(1) Be sure power has been disconnected at the source and remove six screws (1). Open control box cover
(2).
(2) Using multimeter set to measure continuity, check each control relay (3) coil continuity between terminals
A to B. Continuity should be indicated. If no continuity was indicated, replace control relay.
(3) Using multimeter set to measure continuity, check each control relay (3) contact continuity between
terminals 7 to 4 (K3 and K4) and 9 to 6 (K4). No continuity should be indicated. If continuity was
indicated, replace control relay.
(4) If no failure was indicated, close control box cover (2) and install six screws (1).
b.
Removal.
(1) Be sure power has been disconnected at the source and remove six screws (1). Open control box cover
(2).
NOTE
The following procedures apply to both control relays K3 and K4 Quantities given are for each relay.
(2) Tag and disconnect wire leads (4). Do not remove sleeving insulation (5) or faston tab adapters (6) unless
terminals are damaged.
(3) Remove bolt (7), lock washer (8), flat washer (9), and control relay (3). Discard lock washer.
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