Pressure Control, Manual Reset

Electromechanical Pressure Controls P70, P72, P170 Series: Controls For Low Pressure Applications Description The P70, P72, and P170 controls for low pressure applications are designed primarily for low pressure cut-out control, pump-down control, and capacity control on commercial refrigeration and air conditioning applications. These controls are available in several pressure ranges and are compatible with most common refrigerants. They may also be used on other non-corrosive fluid applications. Ammonia-compatible models are also available. Controls also are available in several different electrical ratings and switch configurations. The P72 models provide direct control of 208-240 volt single-phase motors up to 3 hp, and 208-220 volt 3-phase motors up to 5 horsepower. Features All-steel case and cover built to provide long lasting, rugged protection for internal components. "Sight-Set" calibrated pressure adjustment displays a visible pressure scale, fully adjustable through the range without removing the cover (on NEMA 1 enclosure models). MICRO-SET™ differential option allows for precise control on critical low pressure applications. Manual reset lockout option provides "trip free" low pressure lockout that cannot be overridden or reset until pressure returns to specified level. Limited knob adjustment option restricts control adjustment ranges and deters tampering and over-adjustment. Applications P70A and P170A models with Single-Pole Single-Throw (SPST) Open-low switch action are the most popular models, and are typically used for low pressure cut-out and pump-down control. P70 and P170 models are also available with SPST Open-high switch action, and are typically used for capacity control. Models with Single-Pole Double-Throw (SPDT) or 4-wire, 2-circuit switch action allows users to install alarm devices or other control circuits. P72 models have a Double-Pole Single- Throw (DPST) switch with load-carrying contacts that can provide direct control of 208-240 V single-phase motors up to 3 hp, and 208-220 V 3-phase motors up to 5 hp. Refer to DPST Electrical Ratings (P72A, B, C, and D Models). NEMA 1 enclosures are standard on most models. NEMA 3R enclosures are also available.