TM 9-4110-256-14
4-26. CONTROL RELAYS K3 AND K4 TESTING AND REPLACEMENT.
This task covers:
a. Testing
b. Removal
c. Installation
INITIAL SETUP
Materials/Parts:
Tools:
Lock Washers (2)
Heat Gun
1, Appendix G
4, Section III, Appendix B
Lock Washer (1) (K3)
6, Appendix G
Equipment Conditions:
Lock Washer (1) (K4)
6, Appendix G
Refrigeration unit shut down (para 2-7) and power
Sleeving Insulation (3) (K3)
disconnected.
Sleeving Insulation (2) (K4)
Control panel cover open.
Marker tags (4) (K3)
General Safety Instructions:
7, Appendix E
Marker tags (6) (K3)
WARNING
7, Appendix E
High voltage and exposed rotating parts are
used in the refrigeration unit. Personal injury
can result if power is connected.
a. Testing. (See Figure 1-4.)
(1)
Be sure power has been disconnected at the source and remove two bolts (1) and lock washers (2). Open
control box cover (3). Discard lock washers.
(2)
Using multimeter set to measure continuity, check each control relay (4) 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 (4) 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).
(4)
If no failure was indicated, close control box cover (3) and install two new lock washers (2) and bolts (1).
b. Removal.
(1)
Be sure power has been disconnected at the source and remove two bolts (1) and lock washers (2). Open
control box cover (3). Discard lock washers.
NOTE
The following procedures apply to both control relays K3 and K4. Quantities given are for each relay.
(2)
Tag and disconnect wire leads (5). Do not remove sleeving insulation (6) or faston tab adapters (7) unless
terminals are damaged.
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