Johnson Controls P70MA-18 Pressure Control

The Johnson Controls P70MA-18 is a heavy-duty dual pressure control designed for single-device regulation of compressors in commercial refrigeration and HVAC systems. This SPST pressure switch features a versatile low-side range of 20" Hg to 80 psi and a high-side range of 100 psi to 425 psi, making it compatible with a wide array of non-corrosive refrigerants. A critical safety feature for any technician, the high-side includes a manual reset lockout to prevent equipment damage during overpressure events, while the low side operates on an automatic reset for standard cycling. This specific model, encased in a NEMA 1 enclosure, is functionally identical to the P70MA-18C, providing a rugged all-steel housing suitable for demanding mechanical rooms. With its 36-inch capillary and 1/4-inch flare nut, the P70 series controller ensures a reliable connection to the system's high and low-pressure ports without the need for constant adjustment, as this unit is built without external knobs to prevent unauthorized tampering.

• Enhanced System Safety: The high-pressure manual reset lockout ensures the system stays offline following a critical spike, allowing for professional diagnostic before restarting.
• Broad Compatibility: Engineered for use with most non-corrosive refrigerants, making it a staple for commercial cooling and air conditioning applications.
• Simplified Installation: Comes equipped with a 36-inch capillary tube and 1/4-inch flare nut for immediate piping into existing refrigeration lines.
• Anti-Tamper Design: The lack of external adjustment knobs prevents site personnel from altering the precise factory or technician-set points.
• Rugged Construction: Features a durable NEMA 1 steel enclosure that protects internal bellows and switch mechanics from environmental debris.

Is the P70MA-18 compatible with R-410A or R-22?
Yes, this control is designed for use with standard non-corrosive refrigerants common in the industry. Always verify that your system’s maximum pressure does not exceed the 525 psi overpressure rating of this unit.

What is the difference between the P70MA-18 and the P70MA-18C?
Technically, these units are identical. The "C" suffix typically denotes bulk packaging or specific distributor coding, but the performance specifications and pressure ranges remain the same.

How do I reset the high-pressure side after a lockout?
Once the system pressure has dropped below the differential set point, the manual reset button located on the top or front of the enclosure must be depressed to restore the circuit.

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.