Parker Hannifin 903574P ADRHE-6 Discharge Bypass Valve 5/8" ODF 0-80 PSI

The Parker Hannifin 903574P is an ADRHE-6 adjustable discharge bypass valve designed for refrigeration and air conditioning systems. This direct-acting modulating control valve provides an economical method of compressor capacity control by automatically bypassing discharge gas to maintain desired minimum evaporator pressure during low-load conditions.

Key Features:

• 5/8" ODF (flare) connection size for discharge line integration
• Adjustable pressure range: 0 to 80 PSI for customized system control
• 3/4" external equalizer port with 1/4" ODF connection
• Brass construction for durability and corrosion resistance
• Direct-acting pressure-sensing design responds to suction pressure changes
• Modulating operation maintains consistent evaporator pressure
• Maximum rated pressure: 500 PSIG
• Compatible with common refrigerants (excluding ammonia)

Operation:

This discharge bypass valve monitors downstream or suction pressure and responds automatically to changing conditions. When evaporating pressure remains above the valve setting, the valve stays closed and the system operates normally. As suction pressure drops below the preset threshold, the valve opens progressively to bypass hot discharge gas to the low side, preventing coil icing and compressor short cycling during periods of reduced load.

Applications:

Ideal for refrigeration and air conditioning systems that experience variable loads, this valve serves as an alternative to cylinder unloaders or supplements them below the last unloading step. Commonly used in commercial refrigeration, walk-in coolers, and HVAC applications where maintaining minimum evaporator pressure is critical for system protection and efficiency.