15 Evaporator Fan Low Speed Current Too Low (Check Alarm)

Thermo King Alarm Code

Description

Corrective Action

Evaporator Fan Low Speed Current Too Low (Check Alarm) Occurs during Pretrip (PTI) or Function test only. Evaporator fan power consumption is 25% below expected current draw (below 0.6 to 1.2 amps, depending on voltage). Indicates: Defective evaporator fan motor relay Defective or open fan motor internal over temperature protection switch Defective volt or amp meter on relay board Incorrect motor or motor connections

Open evaporator door and make sure all fans rotate freely. Enter Manual Function Test and start evaporator fans on LOW speed. Make sure all fans start on low speed. if a motor does not start and is very hot, wait 10 minutes for internal over temperature switch to close. Check fan motor volts and amps Check volt and ampere meter.

NOTE: **If both alarms 12 and 13; or 14 and 15 are activated, the alarms are caused by a large difference in measured amps. Enter manual Function Test menu and operate evaporator fans on low and high speed. Check the evaporator fan amps measurement. If necessary, check the resistance in the motors: High speed between EF11 and EF12, EF12 and EF13, and EF11 and EF13; Low speed between EF1 and EF2, EF2 and EF3, and EF1 and EF3. Resistance readings should be equal: High speed about 6 Ohms, total of 2 motors; Low speed about 20 Ohms, total of 2 motors.