Johnson Controls P70KA-7 Pressure Control

The Johnson Controls P70KA-7 Pressure Control is a heavy-duty single-pole, double-throw (SPDT) switch engineered specifically for high-pressure applications in industrial refrigeration. Designed for compatibility with ammonia refrigerant (R-717), this control features a robust bellows system that handles non-corrosive liquids and gases common in large-scale chillers and cold storage facilities. This unit operates as an "open high" pressure cutout, providing a critical safety layer by interrupting the circuit when head pressure exceeds the setpoint. With an adjustable range of 50 to 450 psi (350 to 3100 kPa), it offers the precision required for maintaining system integrity under varying loads. The manual reset mechanism ensures that technicians must physically inspect the system after a high-pressure trip, preventing automated cycling that could lead to compressor failure. This model is technically identical to the P70KA-7C, featuring a 4-wire, 2-circuit configuration with 1 normally open and 1 normally closed contact for versatile alarm and control wiring.

Key Benefits

• Ammonia Compatible Construction: Built with materials specifically rated for R-717 ammonia refrigeration, ensuring long-term reliability in harsh industrial environments.
• Field-Adjustable Setpoints: Includes a visible scale for precise high-pressure cutout adjustments between 50 and 450 psi.
• Manual Reset Safety: Requires manual intervention after a trip, facilitating proper diagnostic procedures and preventing short-cycling.
• Dual Circuit Flexibility: The SPDT contact arrangement allows for simultaneous compressor shutdown and remote alarm or pilot light activation.
• Universal Compatibility: Directly replaces the P70KA-7C, making it a standard stock item for contractors servicing industrial racks.

Common Questions

Can the P70KA-7 be used with standard CFC or HFC refrigerants?

Yes, while specifically designed for ammonia use, the bellows and internal components are compatible with all non-corrosive refrigerants, making it a versatile high-pressure limit control for various systems.

How do I wire the manual reset for a lockout circuit?

The 4-wire 2-circuit design allows you to use the normally closed (NC) contacts for the compressor contactor coil while utilizing the normally open (NO) contacts for a lockout relay or failure notification system.

Is there a difference between the P70KA-7 and the P70KA-7C?

There is no functional or technical difference; the P70KA-7 is the direct equivalent to the P70KA-7C and can be used interchangeably in all HVACR industrial applications.

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.