22 Capacity Test 1 Error (Check Alarm)

Thermo King Alarm Code

Description

Corrective Action

Capacity Test 1 Error (Check Alarm) Occurs during Pretrip (PTI) test only. Difference between supply and return air temperature is too small with low speed evaporator fans (less than approximately 4.5C [8 F]) Return air temperature does not reach -18C (0 F) within preset time. Indicates: Incorrect location of supply or return air sensor Air leakage at supply sensor cable Defective supply or return air sensor Interchanged sensor connections incorrect evaporator fan rotation or high speed operation Incorrect refrigeration system operation Container/side panels defective, damaged or leaking

Enter Manual Function Test and start evaporator fans on LOW speed. Then select Sensor Checks test and operate fans 2 to 5 minutes. Check supply, return and evaporator coil (defrost) sensor temperatures. Sensor readings should be the same (evaporator coil may be 0.5 C [1.0 F] lower due to fan motor heat). NOTE: This sensor check does not detect air leakage around the sensor cables. Open evaporator door and inspect evaporator fan rotation. Make sure fans are rotating correctly on low speed. Check the sensor connections. Enter Manual Function Test menu. Start and check current draw of the following components separately and together: compressor, compressor 100%, condenser fan and evaporator fans (low). Check discharge and suction pressure readings. Also check the refrigerant charge. NOTE: This alarm can be activated in ambient temperatures below -10 C (14 F), even under normal conditions.