11 Heater Current Too Low (Check Alarm)

Thermo King Alarm Code

Description

Corrective Action

Heater Current Too Low (Check Alarm) Occurs during Pretrip (PTI) or Function test only. Heater power consumption is 25% below the expected current draw (below approximately) 3.2 amps and 3.8 amps, depending on voltage). Indicates: Defective high evaporator temperature switch Defective heater element or heat relay Defective wire connection Incorrect heaters or heater connections

Enter Manual Function Test and turn heaters ON. Make sure the heat relay energizes. Check current draw on each phase. Current draw should be 4.4 on each phase at 400V (5.1 amps at 460V). If heat relay fails to energize, check evaporator high temperature switch. Switch should be closed at temperatures below 54c (130F); there should be continuity between pins 5 and 6 in plug J19. Check cable No.2 between controller and relay board. Check heater resistance between H1 and H2, H2 and H3, and H1 and H3. Resistance should be about 99 ohms on each leg. Check volt and ampere meter.