Thermo King 914 724, Manual

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Electric Standby Mechanical Diagnosis (Rev. 1/99)
83
Head pressure too high Refrigerant overcharge Remove excess
Air in system Evacuate system
Dirty condenser Clean
Restricted condenser Clean condenser
Condenser fan not running Check fan motor
Condenser fan rotating backwards Check direction
Head pressure too low Refrigerant shortage Repair leak and recharge
Compressor suction or discharge
valve inefficient
Replace compressor
Noisy unit Insufficient compressor oil Add oil to proper level
Mounting bolts loose Tighten
Oil slugging or refrigerant flooding
back
Adjust oil level or refrigerant charge.
Check expansion valve for proper
superheat
Compressor loses oil Shortage of refrigerant Repair leak and recharge
Plugged expansion valve or strainer Clean or replace
Wrong oil viscosity Use proper oil
Short cycling Refer to Unit Short Cycles
Superheat too high Adjust expansion valve
Frosted or sweating suction line Expansion valve set too low,
admitting excess refrigerant
Adjust expansion valve
Heat exchanger internal leak Replace
Hot liquid line Shortage of refrigerant Repair leak and recharge
Frosted liquid line Restricted dehydrator or strainer Replace restricted part
Condenser coils cool when unit is
in cool Refrigerant undercharge Repair leak and recharge
Compressor inefficient Replace compressor
CONDITION POSSIBLE CAUSE REMEDY