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ARMY TM 9-4210-381-14
NAVY EE-000-CA-MMA-010/7053-AC
AIR FORCE TO 35E9-136-31
4-54. TIME DELAY (10 AND 60 SEC) RELAYS (K21 AND K22).
This task covers:
Inspection
Testing
Removal
Installation
INITIAL SETUP:
Tools
Tool kit, service, refrigeration unit (Item 1, Appendix B)
Personnel: 1
Materials:
Varnish, moisture and fungus resistant (Item 16, Appendix E)
Equipment Conditions:
WARNING
Disconnect input power to the air conditioner before performing any internal maintenance. Voltages used
can KILL. Shutting the unit off at the control panel does not disconnect unit power.
1. Disconnect air conditioner input power at source.
2. Remove center front evaporator panel (para 4-22).
3. Open right electric plate (para 4-31).
INSPECTION
1.
Check for loose wire connections (see Figure 4-57).
2.
Check for cracks, signs of overheating, and other visible damage. Replace relay, if defective.
TESTING
1. Using multimeter, check continuity:
Terminal A (+)
to B (-): continuity
1
to 4
: no continuity
1
to 7
: continuity
3
to 6
: no continuity
3
to 9
: continuity
If conditions are not shown above, replace relay.
2.
Apply 24 volts dc across terminals A(+) and B(-) (prime power can be used).
3.
Using multimeter, measure voltage drop between terminals 2 and 5. Voltage indicated should be 19 to 29 volts dc.
After about 10 seconds (K21) or 60 seconds (K22), voltage should drop to less than two volts with external resistor
installed.
4.
Replace relay if it fails above tests.
REMOVAL
Pull relay (1) out of socket by spreading two holding brackets (2).
INSTALLATION
1.
Fungus proof replacement time delay relay per MIL-V-173.
2.
Plug relay (1) into socket.
4-102
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