Unit installation
IOMM ACZ/AGZ-3 ACZ / AGZ-BM 133
ACZ/AGZ Troubleshooting Chart
PROBLEM POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS
1. Main Switch. 1. Close Switch.
2. Fuse Blown. Circuit breakers open 2. Check electrical circuits and motor windings for shorts or
grounds. Investigate for possible overloading. Replace fuse or
reset breakers after fault is corrected. Check for loose or
corroded connections.
3. Thermal overloads tripped 3. Overloads are auto-reset Check unit closely when unit comes
back on line. Allow time for auto-reset.
4. Defective contactor or coil. 4. Repair or replace
5. System Shutdown by equipment protection devices 5. Determine type and cause of shutdown and correct it before
resetting equipment protection switch
6. No cooling required 6. None. Wait until unit class for cooling
7. Liquid line solenoid will not open 7. Repair or replace solenoid coil. Check wiring
8. Motor electrical trouble 8. Check motor for opens, shorts, or burnout
Compressor Will Not
Run
9. Loose wiring 9. Check all wire junctions. Tighten all terminal screws
Compressor Noisy Or
Vibrating
1. Low or no refrigerant charge
2. Compressor running in reverse
3. Improper piping support on suction or discharge
4. Worn compressor isolator bushing
5. Worn Compressor
1. Repair and recharge
2. Check unit and compressor for correct phasing
3. Relocate, add, or remove hangers
4. Replace
5. Replace
1. Noncondensables in system 1. Extract the noncondensables with approved procedures
2. System overcharged with refrigerant 2. Remove excess, check liquid subcooling
High Discharge
Pressure
3. Optional discharge shutoff valve partially closed 3. Open valve
4. FanTrol wiring not correct 4. Check FanTrol wiring
5. Fan not running 5. Check electrical circuit, Check fan motor
6. Dirty condenser coil
7. Air recirculation
6. Clean coil
7. Correct
1. Refrigerant flood back 1. Correct
2. Wind blowing into coil at low ambient 2. Shield coil from direct wind
3. Faulty condenser temperature regulation 3. Check condenser control operation
4. Insufficient refrigerant in system
5. Low suction pressure
4. Check for leaks. Repair and add charge
5. See corrective steps for Low Suction Pressure
Low Discharge
Pressure
6. Only one compressor operating 6. See corrective steps for Compressor Will Not Stage Up
1. Excessive water temperature 1. Check control settings
2. Excessive load 2. Reduce load or add additional equipment High Suction Pressure
3. Expansion valve overfeeding 3. Check remote bulb. Regulate superheat
4. Compressors running in reverse 4. Check for proper phasing
1. Rapid load swings 1. Stabilize load
2. Lack of refrigerant 2. Check for leaks, repair, add charge. Check liquid sight glass
3. Clogged liquid line filter-drier 3. Check pressure drop across filter-drier. Replace
4. Expansion valve malfunctioning 4. Check and reset for proper superheat
5. Condensing temperature to low 5. Check means for regulating condenser temperature
6. Compressor will not unload 6. See corrective steps for Compressor Staging Intervals Too Low
7. Insufficient water flow 7. Adjust flow
8. Evaporator head ring gasket slippage 8. Take pressure drop across vessel and contact factory to obtain
design pressure drop for that vessel
Low Suction Pressure
9. Evaporator dirty
10. Rapid load swings
9. Clean chemically
10. Stabilize load
1. Defective capacity control 1. Replace
2. Faulty thermostat stage or broken wire 2. Replace
Compressor Will Not
Stage Up
3. Stages not set for application 3. Reset thermostat setting for application
1. Thermostat control band not set properly 1. Set control band wider
2. Erratic water thermostat 2. Replace
Compressor Staging
Intervals Too Short
3. Insufficient water flow
4. Rapid load swings
3. Adjust flow
4. Stabilize load
1. Oil hang-up in piping 1. Review refrigerant piping and correct
2. Low oil level 2. Check and add oil
3. Loose fitting on oil line 3. Check and tighten system
4. Level too high 4. Adjust thermal expansion valve
5. Insufficient water flow - Level too high 5. Adjust flow
Compressor Oil Level
Too High Or Too Low
6. Excessive liquid in crankcase - Level too high
7. Short cycling
6. Check crankcase heater. Reset expansion valve for higher
superheat. Check liquid line solenoid valve operation.
7. Stabilize load or increase staging interval
1. Lack of refrigerant 1. Check for leaks and repair. Add refrigerant
2. Excessive compression ring blow-by 2. Replace compressor Compressor Loses Oil
3. Suction superheat too high 3. Adjust superheat
4. Crankcase heater burnout 4. Replace crankcase heater
1. Low voltage during high load conditions 1. Check supply voltage for excessive line drop
2. Defective or grounded wiring in motor 2. Replace compressor motor
Motor Overload Relays
Or Circuit Breakers
Open
3. Loose power wiring or burnt contactors
4. High condenser temperature
5. Power line fault causing unbalanced voltage
3. Check all connections and tighten
4. See corrective steps for High Discharge Pressure
5. Check supply voltage. Notify power company. Do not start until
fault is corrected.
1. Operating beyond design conditions
2. Discharge valve partially shut
1. Add facilities so conditions are within allowable limits
2. Open valve
3. Blown compressor internal gasket 3. Replace gasket
4. Voltage range or imbalance 4. Check and correct
Compressor Thermal
Protection Switch
Open
5. High superheat
6. Compressor bearing failure
5. Adjust to correct superheat
6. Replace compressor