Carrier 69NT40-541-505 Operation And Service Manual page 63

AL21
Cause: One of the 18 VAC controller fuses (F1/F2) is open. Refer to Cd08.
AL22
Cause: Evaporator motor internal protector (IP) is open.
AL23
Cause: Controller fails to detect current draw.
AL24
Cause: Compressor internal protector (IP) is open.
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CONTROL CIRCUIT FUSE (F1/F2)
Component System Sensors
Troubleshooting Check system sensors for short to ground.
Corrective Action Replace defective sensor(s)
Component Wiring
Troubleshooting Check wiring for short to ground.
Corrective Action Repair as needed.
Component Controller
Troubleshooting Controller may have an internal short.
Corrective Action Replace controller, refer to Controller Service
EVAPORATOR IP
Component Evaporator Motor
Troubleshooting Shut down unit, disconnect power, & check Evaporator Motor IP at plug
connection pins 4 & 6.
Corrective Action Replace defective evaporator fan motor, refer to EVAPORATOR FAN MO-
TOR Service
LOSS OF PHASE B
Component Incoming Power
Troubleshooting Check incoming power source.
Corrective Action Correct power source as required.
COMPRESSOR IP
Component Compressor
Troubleshooting Shut down unit disconnect power, & check resistance of compressor wind-
ings at contactor T1-T2, T2-T3.
Corrective Action Monitor unit, if alarm remains active or is repetitive replace the compressor
at the next available opportunity, refer to COMPRESSOR Service
7.8.
search engine
Section 7.14.
4–33
Section 7.20.
Section
T-368