McQuay AGS 120CM/B, Руководство по установке и обслуживанию

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IMM AGS-2 83
Troubleshooting Chart
Table 45, Troubleshooting
PROBLEM POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS
Compressor will not
run.
1. Main power switch open.
2. Unit S1 system switch open.
3. Circuit switch, CS in pumpdown position.
4.
Chilled water flow switch not closed.
5. Circuit breakers open.
6. Fuse blown or circuit breakers tripped.
7. Compressor overload tripped.
8. Defective compressor contactor or contactor coil.
9. System shut down by protection devices.
10. No cooling required.
11. Motor electrical trouble.
12. Loose wiring.
1. Close switch.
2. Check unit status on MicroTech II display. Close switch.
3. Check circuit status on MicroTech II display. Close switch. Check
pump operation for flow.
4. Check unit status on MicroTech display. Close switch.
5. Close circuit breakers.
6. Check electrical circuits and motor windings for shorts or grounds.
Investigate for possible overloading. Check for loose or corroded
connections. Reset breakers or replace fuses after fault is corrected.
7. Overloads are manual reset. Reset overload at button on overload.
Clear alarm on MicroTech II display.
8. Check wiring. Repair or replace contactor.
9. Determine type and cause of shutdown and correct problem before
attempting to restart.
10. Check control settings. Wait until unit calls for cooling.
11. See 6,7,8 above.
12. Check circuits for voltage at required points. Tighten all power wiring
terminals.
Compressor Noisy
or Vibrating
1. Compressor Internal problem.
2. Oil injection not adequate.
1. Contact McQuayService.
2. Check that oil sight glass has oil visible during steady operation
Check pressure drop across oil filter and oil separator sight glasses
Compressor
Overload K2
Tripped or Circuit
Breaker Trip or
Fuses Blown
1. Low voltage during high load condition.
2. Loose power wiring.
3. Power line fault causing unbalanced voltage.
4. Defective or grounded wiring in the motor.
5. High discharge pressure.
1. Check supply voltage for excessive voltage drop.
2. Check and tighten all connections.
3. Check supply voltage.
4. Check motor and replace if defective.
5. See corrective steps for high discharge pressure.
Compressor Will
Not Load or Unload
1. Defective capacity control solenoids.
2. Unloader mechanism defective.
1. Check solenoids for proper operation. See capacity control section.
2. Contact McQuayService .
High Discharge
Pressure
1. Noncondensables in the system.
2.
Fans not running.
3. Fan control out of adjustment.
4. System overcharged with refrigerant.
5. Dirty condenser coil.
6. Air recirculation from fan outlet into unit coils.
7. Air restriction into unit.
1. Remove noncondensables from the condenser coil after shutdown per
EPA regulations.
2. Check fan fuses and electrical circuits.
3. Check that fan setup in the controller matches unit fan number. Check
MicroTech II condenser pressure sensor for proper operation.
4. Check discharge superheat and condenser subcooling. Remove the
excess charge.
5. Clean the condenser coil.
6. Remove the cause of recirculation.
7. Remove obstructions near unit.
Low Discharge
Pressure
1. Wind effect or a low ambient temperature.
2. Condenser fan control not correct.
3. Low suction pressure.
4. Compressor operating unloaded.
1. Protect unit against excessive wind into vertical coils.
2. Check that fan setup in the MicroTech II controller matches unit fan
number. Check VFD fan on units with VFD option.
3. See corrective steps for low suction pressure.
4. See corrective steps for failure to load.
Low Suction
Pressure
1. Inadequate refrigerant charge quantity.
2. Clogged liquid line filter-drier.
3. Expansion valve malfunctioning.
4. Insufficient water flow to evaporator.
5. Water temperature leaving evaporator is too low.
6. Evaporator tubes fouled.
7. Suction valve (partially) closed.
8. Glycol in chilled water system
1. Check liquid line sight glass. Check unit for leaks. Repair and
recharge to clear sight glass at full load, all fans on, 75
°
F min OAT..
2. Check pressure drop across the filter-drier. Replace filter-driers.
3. Check expansion valve superheat and valve opening position.
Replace valve only if certain valve is not working.
4. Check water pressure drop across the evaporator and adjust gpm.
5. Adjust water temperature to higher value.
6. Inspect by removing water piping. Clean chemically.
7. Open valve.
8. Check glycol concentration
Low Oil Level Trip
1. Insufficient oil.
2. Low discharge pressure.
1. Check oil line and separator sight glasses.
2. Faulty EXV.
High Suction
Pressure
1. Excessive load - high water temperature.
2. Compressor unloaders not loading compressor.
3. Superheat is too low.
4.
System overcharged
1. Reduce load or add additional equipment.
2. See corrective steps below for failure of compressor to load.
3. Check superheat on MicroTech II display. Check suction line sensor
installation and sensor.
4. Check charge, an overcharge raises suction pressure