Dwyer A3100 Photohelic Pressure Switch 25 Psi Npt

Product Description

The DWYER A3100 is a Photohelic pressure switch designed for differential pressure measurement and switching in HVAC and industrial process control applications. It combines a visual pressure gauge with adjustable set-point switches, allowing a technician to both read system pressure and trigger control outputs from a single instrument. The unit operates up to 25 psi maximum with a 2% accuracy rating and accepts a 1/8 inch NPT threaded connection. The Photohelic design integrates a Magnehelic-style gauge with photo-electric switching elements, making it suited for dust collector controls, air handler monitoring, and filter status applications.

This pressure switch is commonly installed in commercial and industrial HVAC systems, cleanrooms, dust collection equipment, and air handling units where both pressure indication and automatic switching are required. It is appropriate for applications involving air, natural gas, and other non-corrosive gases. The 100 inch water column range and 120 degrees F maximum temperature rating make it suitable for duct pressure monitoring and filter differential pressure control. Licensed HVAC technicians and instrumentation technicians are the typical installers for this type of device.

Key Features

• Combines pressure gauge indication with adjustable switching control in one instrument
• 25 psi maximum operating pressure with 2% full-scale accuracy
• 1/8 inch NPT threaded process connection for standard instrument piping
• 100 inch water column pressure range for low-differential duct and filter applications
• 120 degrees F maximum temperature rating for typical mechanical room and duct environments

Compatibility

Designed as an OEM-style replacement or direct installation Photohelic pressure switch for commercial HVAC air handling, dust collection, and industrial process control systems requiring differential pressure switching via NPT threaded connections.

Installation Notes

Installation should be performed by a licensed HVAC technician or instrumentation technician familiar with low-pressure pneumatic instrument piping. De-energize the control circuit and isolate the process pressure before connecting or disconnecting the instrument. Use appropriate thread sealant on the 1/8 inch NPT fitting and avoid over-tightening, which can damage the port. Verify set-point switch adjustment and pressure range match the system design requirements before returning the system to service.