Carrier NDK33BN0KB, Operation & Service Manual

Page: 260 / 270

62-61753-21 10-8
INDICATION/
TROUBLE
POSSIBLE CAUSES
REFERENCE
SECTION
10.4.9 Control System Malfunction
Will not control Sensor defective 8.7.7
Relay(s) defective Check
Microprocessor controller malfunction
Check
10.4.10 No Evaporator Air Flow Or Restricted Air Flow
No or partial evaporator
air flow Check return air bulkhead and air chute. Ensure return air
is not restricted and chute is in good condition Clean, repair or
replace.
Check coil for even air flow with no "dead" spots. Clean. 8.6.2
Frost on coil. To check defrost, run unit in cooling and
place in manual defrost. 3.9
Defrost air switch (DAS) defective or out of calibration 8.6.13
Evaporator fan Evaporator blower loose or defective 8.7.2
Evaporator blower rotating backwards 8.7.2
10.4.11 Electronic Expansion Valve Malfunction
Low suction pressure Incorrect software and/or controller Configuration Check
Excessive frost on evaporator coil. Manually defrost. 3.9
Suction service valve partially closed Open
Filter drier partially plugged 8.6.5
Low refrigerant charge 8.5.4
No evaporator air flow or restricted air flow 8.6.2
Evaporator fans rotating backwards 8.7.2
Loose or insufficiently clamped suction temperature sen-
sor Check
Failed suction pressure transducer 8.6.12
Failed unloader valve 8.6.9
Electronic expansion valve malfunction 8.6.8
High suction pressure with low
superheat improperly seated power head Ensure power
head is locked in
place
Failed suction pressure transducer 8.6.12
Foreign material in valve 8.6.8
Electronic expansion valve malfunction 8.6.8
Liquid slugging in compressor Failed suction pressure transducer 8.6.12
Electronic expansion valve malfunction 8.6.8