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Except for extremely small releases of refrigerant such as what occurs when disconnecting service
hoses (diminimous release), a technician who knowingly releases or vents refrigerant to the
atmosphere is in violation of this regulation. Refrigerant purchasers must be certifi ed technicians
and have a valid EPA certifi cation card.
5.4 Important Refrigeration Components
5.4.1. Expansion Valve
Each refrigerant circuit has an adjustable thermo-expansion valve (TXV). These are factory adjusted
to their nominal rating. Any fi eld adjustment should be to fi ne tune a system that has stabilized and
already has acceptable operating parameters.
5.4.2. High Pressure Cutout Switch
Each refrigerant circuit is protected by a high head pressure cutout switch with a manual reset button.
The cutout pressure rating for refrigerant R-22 or R-407C is 400 psi. Physical location is near the
compressor which may be either in the evaporator or the condensing section.
5.4.3. Low Pressure Cutout Switch
Each circuit also contains a low suction pressure cutout switch with automatic reset. The cutout
pressure rating for this switch is 30 psi. Physical location is near the compressor which can be either
in the evaporator or the condensing section.
