Johnson Controls P74BA-1 Pressure Control

The Johnson Controls P74BA-1 is a robust differential pressure control designed for demanding commercial HVACR applications, including chiller proof of flow and refrigeration compressor lube oil monitoring. Engineered with stainless steel bellows, this SPST pressure switch effectively measures the variance between two sensing points, opening the circuit on a decrease in pressure difference. This action is critical for protecting equipment from low-flow conditions or insufficient lubrication. The unit features an adjustable pressure range of 8 to 70 psi and a switch differential adjustable from 8 to 30 psi, allowing for precise field calibration via the external scale. For streamlined installation, the P74BA-1C includes a 36-inch capillary with a 1/4-inch flare nut and a universal mounting bracket. With a heavy-duty electrical rating of 20 Amps at up to 600 VAC/VDC, this Johnson Controls differential switch provides high-capacity switching and long-term reliability in high-vibration machine rooms.

• Universal Compatibility: Designed for HVAC proof of flow in water chillers, condensers, and heating coils, as well as refrigeration oil pressure sensing.
• Superior Durability: Equipped with stainless steel bellows and heavy-duty elements that withstand high overrun pressures and corrosive environments.
• Precise Adjustment: Features an externally adjustable setpoint with a calibrated scale, enabling technicians to set differential pressure limits without removing the cover.
• Reliable Switching: Utilizes a high-force contact structure to eliminate contact bounce and ensure a long life contact cycle even under heavy electrical loads.
• Simplified Installation: The inclusive Style 13 pressure element with 36" capillary and 1/4" flare nut simplifies connection to standard refrigeration ports.

How do I adjust the setpoint on the Johnson Controls P74BA-1?
The operating point is adjusted by rotating the disk visible through the cover. Use the calibrated scale to align the pointer with your required differential pressure setpoint. Internal adjustments may be required for the switch differential on specific models.

Can this control be used for water flow detection?
Yes, the P74BA-1 is frequently used as a water flow pressure switch in chiller systems to trigger an alarm or shut down the compressor if the pressure drop across the heat exchanger falls below safe levels.

What is the difference between the P74BA and other P74 models?
The P74BA specifically features SPST contacts that close on an increase in differential pressure (or open on a decrease). Other models, like the P74EA, utilize SPDT contacts for more complex signaling or floating control 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.