Agz Troubleshooting Chart - McQuay AGZXXXBS Series Installation, Operation And Maintenance Manual

AGZ Troubleshooting Chart

PROBLEM
1.
2.
3.
Compressor Will
4.
Not Run
5.
6.
7.
8.
9.
1.
2.
Compressor Noisy
3.
Or Vibrating
4.
5.
1.
2.
3.
High Discharge
4.
Pressure
5.
6.
7.
1.
2.
3.
Low Discharge
4.
Pressure
5.
6.
1.
2.
High Suction
Pressure
3.
4.
1.
2.
3.
4.
Low Suction 5.
Pressure
6.
7.
8.
9.
10.
1.
Compressor Will
2.
Not Stage Up
3.
1.
Compressor
2.
Staging Intervals
Too Short
3.
4.
Table continued on next page.
IOMM AGZ-5
POSSIBLE CAUSES
Main switch.
Fuse blown. circuit breakers open
Thermal overloads tripped
Defective contactor or coil.
System shutdown by equipment protection devices
No cooling required
Liquid line solenoid will not open
Motor electrical trouble
Loose wiring
Low or no refrigerant charge
Compressor running in reverse
Improper piping support on suction or discharge
Worn compressor isolator bushing
Worn Compressor
Noncondensables in system
System overcharged with refrigerant
Optional discharge shutoff valve partially closed
FanTrol wiring not correct
Fan not running
Dirty condenser coil
Air recirculation
Refrigerant flood back
Wind blowing into coil at low ambient
Faulty condenser temperature regulation
Insufficient refrigerant in system
Low suction pressure
Only one compressor operating
Excessive water temperature
Excessive load
Expansion valve overfeeding
Compressors running in reverse
Rapid load swings
Lack of refrigerant
Clogged liquid line filter drier
Expansion valve malfunctioning
Condensing temperature too low
Compressor will not unload
Insufficient water flow
Evaporator head ring gasket slippage
Evaporator dirty
Rapid load swings
Defective capacity control
Faulty thermostat stage or broken wire
Stages not set for application
Thermostat control band not set properly
Faulty water temperature sensor
Insufficient water flow
Rapid load swings
AGZ 026B through 130B
POSSIBLE CORRECTIVE STEPS
1. Close switch.
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. Overloads are auto-reset. Check unit closely when unit
comes back on line. Allow time for auto-reset.
4. Repair or replace
5. Determine type and cause of shutdown and correct it
before resetting equipment protection switch.
6. None. Wait until unit calls for cooling.
7. Repair or replace solenoid coil. Check wiring.
8. Check motor for opens, shorts, or burnout.
9. Check all wire junctions. Tighten all terminal screws.
1. Repair and recharge
2. Check unit and compressor for correct phasing
3. Relocate, add, or remove hangers
4. Replace
5. Replace
1. Extract the noncondensables with approved procedures.
2. Remove excess, check liquid subcooling.
3. Open valve.
4. Check FanTrol wiring.
5. Check electrical circuit, Check fan motor.
6. Clean coil.
7. Correct.
1. Correct.
2. Shield coil from direct wind, Wind guards are available.
3. Check condenser control operation.
4. Check for leaks. Repair and add charge.
5. See corrective steps for Low Suction Pressure.
6. See corrective steps for Compressor Will Not Stage Up.
1. Check control settings.
2. Reduce load or add additional equipment.
3. Check remote bulb. Regulate superheat.
4. Check for proper phasing.
1. Stabilize load.
2. Check for leaks, repair, add charge. Check liquid sight
glass.
3. Check pressure drop across filter drier. Replace.
4. Check and reset for proper superheat.
5. Check means for regulating condenser temperature.
6. See corrective steps for Compressor Staging Intervals
Too Low.
7. Adjust flow.
8. Take pressure drop across vessel and contact factory to
obtain design pressure drop for that vessel.
9. Clean chemically.
10. Stabilize load.
1. Replace.
2. Replace.
3. Reset thermostat setting for application.
1. Set control band wider.
2. Replace.
3. Adjust flow.
4. Stabilize load.
101