P32AC-2C Johnson Controls Pressure Control

Overview

The Johnson Controls P32AC-2C is a highly sensitive differential pressure switch designed to sense the flow of air in ducts or monitor low-pressure differences in HVAC systems. It is commonly used to protect equipment like electric strip heaters by opening the circuit and de-energizing the system when airflow stops. The control utilizes a spring-loaded diaphragm mechanism that activates a snap switch in response to changing pressure conditions, making it effective as a standalone differential switch, a positive gauge pressure switch, or a vacuum detector.

Features

• Easy-to-read, field-adjustable setpoint scale plate.
• Small, compact design with versatile mounting brackets (includes U-bracket).
• Durable construction featuring a cold-rolled steel internal chassis with zinc plating and a molded polycarbonate cover.
• High-quality Buna-N diaphragm to withstand demanding air conditions.
• Pre-installed 1/4 inch angle barb fitting for easy pressure tubing attachment.
• NEMA 1 general-purpose enclosure protecting indoor electrical connections.

Specifications

• Pressure Set Point Range: 0.05 to 5.0 inches WC (Water Column)
• Switching Action: SPDT (Single-Pole, Double-Throw) snap-acting switch
• Electrical Ratings: Up to 1/2 HP at 120/240 VAC; 15 A non-inductive resistive load at 24 to 277 VAC
• Connections: 1/8 inch female NPT internal / 1/2 inch NPSM external (high-pressure metal side) and molded 1/8 inch NPT (low-pressure side)
• Ambient Operating Temperature: -40°F to 165°F (-40°C to 74°C)
• Maximum Overpressure: 1 PSIG (6.9 kPa) at either connection

Applications

• Airflow proving with electric duct heaters or humidifiers.
• Maximum airflow control for variable air volume (VAV) systems.
• Clogged or dirty filter status detection and monitoring.
• Detection of icing on air conditioning coils to initiate defrost cycles.
• Reheat duct-powered systems and overall pressure safety monitoring.