104 AGR 055A through 100A IOMM AGR
AGR Troubleshooting Chart
PROBLEM POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS
Compressor will not
1. Main Switch. 1. Close Switch.
Run
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 safety devices 5. Determine type and cause of shutdown and correct it before
resetting safety switch
6. No cooling required 6. None. Wait until unit calls 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
9. Loose wiring 9. Check all wire junctions. Tighten all terminal screws
Compressor noisy
1. Compressor running in reverse 1. Check unit and compressor for correct phasing
or vibrating
2. Improper piping support on suction or discharge 2. Relocate, add, or remove hangers
3. Worn compressor isolator bushing 3. Replace
4. Worn Compressor 4. Replace
High Discharge
1. Noncondensables in system 1. Purge the noncondensables
Pressure
2. System overcharged with refrigerant 2. Remove excess, check liquid subcooling
3. 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 6. Clean coil
Low Discharge
1. Wind blowing into coil at low ambient 1. Shield coil from direct wind
Pressure
2. Faulty condenser temperature regulation 2. Check condenser control operation
3. Insufficient refrigerant in system 3. Check for leaks. Repair and add charge
4. Low suction pressure 4. See corrective steps for Low Suction Pressure
5. Only one compressor operating 5. See corrective steps for Compressor Will Not Stage Up
High Suction
1. Excessive water temperature 1. Check control settings
Pressure
2. Excessive load 2. Reduce load or add additional equipment
3. Expansion valve overfeeding 3. Check remote bulb. Regulate superheat
4. Compressors running in reverse 4. Check for proper phasing
Low Suction
Pressure
1. Lack of refrigerant 1. Check for leaks, Repair and add charge. Check liquid
sightglass
2. Clogged liquid line filter drier 2. Check pressure drop across filter drier. Replace
3. Expansion valve malfunctioning 3. Check and reset for proper superheat
4. Condensing temperature to low 4. Check means for regulating condenser temperature
5. Compressor will not unload 5. See corrective steps for Compressor Staging Intervals Too Low
6. Insufficient water flow 6. Adjust flow
7. Evaporator head ring gasket slippage 7. Take pressure drop across vessel and contact factory to obtain
design pressure drop for that vessel
8. Evaporator dirty 8. Clean chemically
Compressor will not
1. Defective capacity control 1. Replace
stage up
2. Faulty thermostat stage or broken wire 2. Replace
3. Stages not set for application 3. Reset thermostat setting for application
Compressor Staging
1. Thermostat control band not set properly 1. Set control band wider
Intervals to Short
2. Erratic water thermostat 2. Replace
3. Insufficient water flow 3. Adjust flow
Compressor Oil
1. Low oil level 1. Check and add oil
Level Too high or
2. Loose fitting on oil line 2. Check and tighten system
Too Low
3. Level too high 3. Adjust thermal expansion valve
4. Insufficient water flow - Level too high 4. Adjust flow
5. Excessive liquid in crankcase - Level too high 5. Check crankcase heater. Reset expansion valve for higher
superheat. Check liquid line solenoid valve operation.
Compressor loses
1. Lack of refrigerant 1. Check for leaks and repair. Add refrigerant
Oil
2. Excessive compression ring blow-by 2. Replace compressor
3. Suction superheat too high 3. Adjust superheat
4. Crankcase heater burnout 4. Replace crankcase heater
Motor Overload
1. Low voltage during high load conditions 1. Check supply voltage for excessive line drop
Relays or Circuit
2. Defective or grounded wiring in motor 2. Replace compressor motor
Breakers Open
3. Loose power wiring 3. Check all connections and tighten
4. High condenser temperature 4. See corrective steps for High Discharge Pressure
5. Power line fault causing unbalanced voltage 5. Check supply voltage. Notify power company. Do not start until
fault is corrected.
Compressor
1. Operating beyond design conditions 1. Add facilities so conditions are within allowable limits
Thermal Protection
2. Discharge valve partially shut 2. Open valve
Switch Open
3. Blown compressor internal gasket 3. Replace gasket
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