Johnson Controls P70GA-27 Pressure Control

The Johnson Controls P70GA-27 is a dual-circuit low pressure control engineered for precision monitoring in commercial refrigeration, HVAC, and pneumatic systems. This unit features a versatile 20 to 100 PSI pressure range and an open low operation (opens on pressure drop), making it essential for compressor protection and system cycling. The hardware includes a 4-wire 2-circuit configuration with one normally open (NO) and one normally closed (NC) contact, allowing for simultaneous control of secondary auxiliary circuits or alarm signals. Designed with a 1/4" FNPT connection, this Penn pressure switch ensures a secure fit in standard HVACR pressure monitoring applications. Its rugged construction is built to handle the vibratory demands of industrial environments while maintaining setpoint accuracy. Technicians rely on the P70GA-27 for its field-proven reliability and straightforward integration into existing control strings, ensuring critical safety parameters are met without system drift.

Key Benefits for Technicians:

• Dual Circuit Versatility: The 4-wire, 1 NO / 1 NC setup allows for independent control of both the primary load and a status indicator or alarm.
• Broad Compatibility: Standard 1/4 inch FNPT threads and a variable 20-100 PSI scale make it a universal fit for various low-side applications.
• Robust Mechanical Action: High-quality internal bellows and contact structures are designed for high-cycle industrial service.
• Precise Low Pressure Cut-out: Protects compressors from vacuum operation and prevents evaporator freeze-ups in refrigeration cycles.

Common Questions:

What is the difference between the NO and NC circuits on this control?
The normally closed (NC) circuit typically handles the primary compressor or motor load, opening to stop operation on a pressure drop. The normally open (NO) circuit closes on that same drop, which is commonly used to trigger a warning light or a remote BMS notification.

Can the P70GA-27 be used with all refrigerants?
This control is compatible with all non-corrosive refrigerants. For ammonia systems, check for a compatible bellows version specifically rated for R-717.

Does this unit come with a manual reset?
No, the P70GA-27 is an automatic reset control, meaning it will re-close the circuit once the pressure rises above the setpoint plus the differential.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.