As we discuss in this brief, the administrationâs reports to the court do not preclude the Legislature from assessing the measures identified by the administration and considering its own strategy for compliance with the court ruling based on its priorities.
The two most common causes of low head pressure at an air conditioner or heat pump compressor motor are: 1  Refrigerant under-charge, due to a refrigerant leak or improper charge.  TXV (TEV) malfunction, over-metering refrigerant.
The problem with dumping high temperature refrigerant vapor into the cold (iced, needs defrosting) evaporator is that it causes it to begin to condense - back pressure of the gas goes up and head pressure at the condenser goes down - now liquid refrigerant can back up to the compressor (where it would cause damage).