Trane SCIH - Troubleshooting Performance Issues; Insufficient Cooling Causes; Unit Short Cycles; Fan Not Running With Compressor

SXIH-SVX01C-EN 33
Maintenance
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote disconnects before servicing. Follow proper
lockout/tagout procedures to ensure the power can not be inadvertently energized. Failure to
disconnect power before servicing could result in death or serious injury.
Problem Remedy
Insufficient cooling
Possible cause
1. Insufficient air flow due to:
• dirty evaporator
• ice on evaporator coils (indicates airflow restriction
through evaporator)
• dirty filter
• obstructed discharge air intake
• fan motor not running
• evaporator fan or fan wheel slipping on motor shaft
1. Correct as follows:
•clean
• defrost (using fan operation only)
• clean or replace filter
• remove obstruction
• check electrical system
• adjust fan position, tighten set screw on fan wheel
2. Heat gain or loss in room exceeds unit capacity 2. Refer to original load calculations. Recalculate heat gain or
loss.
3. Defective compressor 3. Replace, if necessary.
4. Insufficient refrigerant charge indicated by
• low wattage
• condenser air outlet cold
4. Check refrigerant charge pressure with gauges. If refrigerant
is low, recharge system.
5. Overcharge of refrigerant indicated by high
wattage and sweating of the compressor return
line
5. Reclaim excess refrigerant.
6. Thermostat not set for full cooling 6. Refer to thermostat operating instructions.
7. Insufficient airflow through condenser due to:
• dirty condenser
• loose belt
• fan loose on shaft
7. Correct as follows:
• clean coil
• verify drive is adjusted correctly
• tighten fan on shaft
8. Cutout on high pressure 8. See that air is flowing and that damper is set properly.
9. Only one refrigerant circuit operational in 2-
circuit units
9. Reset high pressure cutout on inoperative circuit. Check
contactor in inoperative circuit.
Problem Remedy
Unit short cycles
Possible cause
1. Remote thermostat 1. Repair or replace
2. Loose connection in electrical unit 2. Trace and repair
3. Thermostat contacts fluttering 3. Repair or replace
4. Air flow to evaporator is restricted 4. Flush or blow dirt out of coil
5. Insufficient charge 5. Reclaim, evacuate, recharge per nameplate
Problem Remedy
Compressor starts and runs, but fan does not run.
Possible cause
1. Faulty switch 1. Replace
2. Open fan motor coil circuit 2. Replace
3. Fan binding on shroud or venturi ring 3. Adjust fan mounting
maintenance procedures