07 R-134 Compressor Current Too Low (Check Alarm)

Thermo King Alarm Code

Description

Corrective Action

Compressor Current Too Low (Check Alarm) Occurs during Pretrip (PTI) or Function test only. Compressor power consumption is 25% below expected current draw (below approximately 9 amps). Indicates: Defective or open fuse CB 7A, high pressure cutout switch or connection in plug j19 between pins 7 & 8 No signal on plug J11 on pin 8 Defective compressor relay Defective volt or amp meter on relay board Low refrigerant charge Defective compressor or valve plate

Enter Manual Function Test menu. Start and  check current draw of the following components separately and together: compressor, compressor 25%, condenser fan and evaporator fan (high and low). If relay does NOT energize and the LED above the compressor relay is NOT ON, check for a defective cable No.2, main relay board or controller. Check discharge and suction pressure gauge readings. Evaluate readings based on current cargo and ambient temperatures. Check volt and ampere meter. Check power supply volts.

NOTE: *If both alarms 06 and 07 are activated, the alarms are caused by a large difference in measured amps. Enter Function Test and start condenser fan, compressor, compressor 100% and evaporator fans on HIGH speed. Check the amps measurements. if necessary, check the resistance of the motor windings.