Johnson Controls Penn P70MA-1 - User Manual

Master Catalog 125
Pressure Controls Section P
Product/Technical Bulletin P70
Issue Date 0900
© 2000 Johnson Controls, Inc. 1
Code No. LIT-125455 www.johnsoncontrols.com
The P70, P72, and P170 controls for dual pressure
applications are designed primarily for use as
combination high and low pressure controls on
commercial refrigeration and air conditioning
applications.
These controls are available in several pressure
ranges and are compatible with most common
refrigerants. Ammonia compatible models are also
available.
These controls respond directly to system pressure
changes on both high and low sides, and can provide
single-device control of the compressor.
Controls are available in several different electrical
ratings and switch configurations, including
independent high and low pressure switches
(on P70S and P170S models). The P72 models
provide direct control of 208-240 volt, single-phase
motors up to 3 horsepower, and 208-220 volt, 3-phase
motors up to 5 horsepower.
Figure 1: P70SA-1 Dual Pressure Control
Features and Benefits
❑ All Steel Case and Cover Provides long lasting, rugged protection for
internal components
❑ “Sight-Set” Calibrated
Pressure Adjustments
Provides visible pressure scales, fully
adjustable through all ranges without
removing the cover
❑ MICRO-SET Differential
Adjustment Option
Allows for precise pressure control of low
pressure applications
❑ Independent High and Low
Pressure Switches
(P70S and P170S Models)
Satisfies a variety of dual pressure application
wiring requirements with a single versatile
control
❑ Convertible, High Pressure
Reset–Auto Reset or
Manual Reset Lockout
(P70S and P170S Models)
Reduces inventory—one control can be
adapted to several dual pressure applications
in the field
P70, P72, and P170 Controls for
Dual Pressure Applications

Johnson Controls Penn P70MA-1 Specifications

General

Mounting	Surface mount
Enclosure Rating	NEMA 1
Application	HVAC Temperature Control
Input Voltage	24 VAC
Humidity Range	0% to 95% RH

Summary

Application and Operation

Important Usage Guidelines

Critical notes on control usage, system design, and the necessity of safety devices.

Ammonia Application Precautions

Specific hazards related to ammonia's corrosiveness and required installation practices.

Control Actuation Principles

Explains how pressure changes operate bellows and switches to control compressors.

Mounting and Pressure Connections

General Mounting Guidelines

Advice on selecting an accessible position, maintaining upright mounting, and ensuring proper line drainage.

Capillary Tube Handling

Installation and Wiring Safety

Capillary Tube and Connection Care

Electrical Safety Warning

Crucial instruction to disconnect power before wiring to prevent electrical shock or damage.

Control Adjustments

Low Side Adjustment Types

High Side Adjustment and Cautions

Adjustment Procedures

Setting Pressure Setpoints

Manual Reset Operation

Explains manual reset lockout and procedures for resetting the control after a trip.

High Pressure Reset and Knob Adjustment

Convertible High Pressure Reset

Steps to change high pressure reset from automatic to manual mode.

Limited Knob Adjustment

Electrical Ratings

SPST and SPDT Ratings

4-wire and DPST Ratings