Head-Pressure Control Valve Test and operating pressures

Excessive leak testing or operating pressures may damage these valves and reduce the life of the operating members. For leak detection, an inert dry gas such as nitrogen or carbon dioxide can be added to an idle system to supplement the refrigerant pressure. Remove the cap and adjust the adjustment screw with the proper wrench. Check the manufacturer’s recommended pressures before making adjustments.

Refrigerant and charging procedures require that enough refrigerant be available for flooding the condenser at the lowest expected ambient temperature. There must still be enough charge in the system for proper operation. Ashortage of refrigerant will cause hot gas to enter the liquid line and the expansion valve. Refrigeration will cease.

The receiver must have sufficient capacity to hold at least all of the excess liquid refrigerant in the system. This is because such refrigerant will be returned to the receiver when high-ambient conditions prevail. If the receiver is too small, liquid refrigerant will be held back in the condenser during high-ambient condition. Excessively high discharge pressures will be experienced.

Follow the manufacturer’s recommendations for charging the system. Procedures may vary with different valve manufacturers.

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