66 AGZ 010B through 034B IOMM AGZB1
Troubleshooting Chart
!
WARNING
Troubleshooting can present risks of severe personal injury or death from burns, cuts,
electrocution, strangulation and asphyxiation. Troubleshooting must be done by trained,
experienced technicians only.
Table 22, Troubleshooting Chart
PROBLEM POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS
COMPRESSOR
WILL NOT RUN
1. Main switch open
2. Fuse blown, breakers open
3. Thermal overloads tripped
4. Defective contactor or coil
5. System off by protection device
6. No cooling required
7. Liquid line solenoid will not open
8. Motor electrical problem
9. Loose wiring
1. Close switch
2. Check electrical circuits and motor windings for
shorts. Check for overloads and loose
connections. Replace fuse or reset breaker.
3. Check unit when back on line, auto reset
4. Repair or replace
5. Determine cause and correct
6. None, should start on call for cooling
7. Repair or replace coil
8. Check motor for open or short circuit, or burnout
9. Check all wire junctions. Tighten all terminals.
COMPRESSOR
NOISY OR
VIBRATING
1. Refrigerant flooding compressor
2. Improper line support
3. Worn compressor
1. Check expansion valve setting
2. Relocate or add supports
3. Replace
HIGH
DISCHARGE
PRESSURE
1. Noncondensables in system
2. Refrigerant overcharge
3. Fan not running
4. Dirty condenser coils
5. FanTrol out of adjustment
1. Remove with authorized procedures
2. Remove excess
3. Check electrical circuit
4. Clean coil
5. Adjust FanTrol setting
LOW
DISCHARGE
PRESSURE
1. Faulty condenser control
2. Low refrigerant charge
3. Low suction pressure
1. Check condenser control operation
2. Check for leaks. Add refrigerant
3. See low suction pressure steps below
HIGH SUCTION
PRESSURE
1. Excessive load
2. Expansion valve overfeeding
1. Reduce load or add capacity
2. Check remote bulb. Regulate superheat
LOW SUCTION
PRESSURE
1. Lack of refrigerant
2. Evaporator dirty
3. Clogged filter-drier
4. Expansion valve malfunctioning
5. Low condensing temperature
1. Check for leaks. Repair and replace refrigerant.
2. Clean chemically
3. Replace
4. Check and adjust for proper superheat
5. Check discharge pressure control settings
UNIT WILL NOT
LOAD OR
UNLOAD
1 Faulty controller sensor/broken wire
2. Stages not set for application
1. Replace
2. Adjust thermostat setting
LOAD/UNLOAD
INTERVAL TOO
SHORT
1. Erratic water thermostat
2. Insufficient water flow
1. Replace
2. Adjust flow
COMPRESSOR
LOSES OIL
1. Lack of refrigerant
2. Suction superheat too high
3. Crankcase heater burned out
1. Check for leaks and repair
2. Adjust superheat
3. Replace crankcase heater
MOTOR
OVERLOAD
RELAYS OPEN
OR BLOWN
FUSES
1. Low voltage during high loads
2. Defective or grounded motor wiring
3. Loose power wiring
4. High condensing temperature
5. Unbalanced voltage
1. Check supply voltage
2. Replace compressor
3. Check all connections and tighten
4. See steps for high discharge pressure
5. Check voltage. Contact power company.
COMPRESSOR
THERMAL
SWITCH OPEN
1. Operating beyond design conditions 1. Add facilities so conditions are within allowable
limits
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