Carrier 69NT40-511-310 - Abnormal Pressures (Cooling); Abnormal Noise or Vibrations; Controller Malfunction

5-3
T -296
CONDITION POSSIBLE CAUSE
REMEDY/
REFERENCE
SECTION
5.6 UNIT WILL NOT DEFROST PROPERLY --Continued
Frequent defrost Wet load Normal
5.7 ABNORMAL PRESSURES (COOLING)
Condenser coil dirty 6.10
Condenser fan rotating backwards 6.11
Condenser fan inoperative 6.11
High discharge pressure
Refrigerant overcharge or noncondensibles 6.7.1
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Discharge pressure regulator valve defective Replace
Discharge service valve partially closed Open
Suction modulation valve malfunction 6.18
Suction service valve partially closed Open
Filter-drier partially plugged 6.13
Low refrigerant charge 6.7.1
Expansion valve defective 6.14
Low suction pressure
No evaporator air flow or restricted air flow 6.15
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Excessive frost on evaporator coil 5.6
Evaporator fan(s) rotating backwards 6.16.3
Discharge pressure regulator valve defective Replace
Suction modulation valve malfunction 6.18
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Heat exchanger defective Replace
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sures tend to equalize when unit
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Compressor valves defective 6.8
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is operating
Compressor cycling/stopped Check
5.8 ABNORMAL NOISE OR VIBRATIONS
Loose mounting bolts T ighten
Worn bearings 6.8
Compressor
Worn or broken valves 6.8
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Liquid slugging 6.14
Insufficient oil 6.8.6
Bent, loose or striking venturi Check
Condenser or Evaporator Fan
Worn motor bearings 6.11/6.16
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Bent motor shaft 6.11/6.16
5.9 CONTROLLER MALFUNCTION
Defective Sensor 6.21
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Defective wiring Check
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Fuse (F1, F2) blown Replace
Stepper motor suction modulation valve circuit malfunction 6.18
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