What is a common indication of a low refrigerant charge in a Thermo King unit?

A common indication of a low refrigerant charge in a Thermo King unit is insufficient cooling or frost build-up on the evaporator coils. When the refrigerant charge is low, there is not enough refrigerant circulating through the system to absorb the heat effectively. This leads to a decrease in the unit's cooling capacity, resulting in inadequate temperature control.

Due to the lower amount of refrigerant, the evaporator coils can become too cold as they attempt to cool down the air passing over them. This can cause moisture in the air to freeze on the coils, resulting in frost build-up. Such frost accumulation can further impede airflow and exacerbate cooling issues, ultimately leading to higher compressor loads and potential system damage if not addressed.

Recognizing insufficient cooling or frost build-up as a symptom can prompt technicians to investigate refrigerant levels and help in maintaining the efficient operation of the Thermo King unit.