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5-3
T-317
CONDITION
POSSIBLE CAUSE
REMEDY/
REFERENCE
SECTION
5.6 UNIT WILL NOT DEFROST PROPERLY --Continued
Frequent defrost
Wet load
Normal
5.7 ABNORMAL PRESSURES (COOLING)
High discharge pressure
Condenser coil dirty
6.10
Condenser fan rotating backwards
6.11
Condenser fan inoperative
6.11
Refrigerant overcharge or noncondensibles
6.7.1
Discharge pressure regulator valve defective
Replace
Discharge service valve partially closed
Open
Suction modulation valve malfunction
6.18
Low suction pressure
Suction service valve partially closed
Open
Filter-drier partially plugged
6.13
Low refrigerant charge
6.7.1
Expansion valve defective
6.14
No evaporator air flow or restricted air flow
6.15
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
Suction and discharge pres-
sures tend to equalize when unit
is operating
Heat exchanger defective
Replace
Compressor valves defective
6.8
Compressor cycling/stopped
Check
5.8 ABNORMAL NOISE OR VIBRATIONS
Compressor
Loose mounting bolts
Tighten
Worn bearings
6.8
Worn or broken valves
6.8
Liquid slugging
6.14
Insufficient oil
6.8.6
Condenser or Evaporator Fan
Bent, loose or striking venturi
Check
Worn motor bearings
6.11/6.16
Bent motor shaft
6.11/6.16
5.9 CONTROLLER MALFUNCTION
Will not control
Defective Sensor
6.23
Defective wiring
Check
Fuse (F1, F2) blown
Replace
Stepper motor suction modulation valve circuit malfunction
6.18