Description
Dwyer A3002 Photohelic Pressure Switch/Gage Overview
The Dwyer A3002 Photohelic Pressure Switch/Gage is a versatile, all-in-one instrument that combines accurate differential pressure measurement with the convenience of two independently adjustable set-point switches — all in a single compact unit. Designed for HVAC, industrial, and clean-room applications, the Photohelic series is a trusted solution for monitoring filter loading, fan and blower performance, duct static pressure, and more.
Key Features
- Dual-function design: combines a differential pressure gage and two adjustable SPDT switches in one instrument
- Pressure range: 0–2.0″ W.C. (inches water column)
- Process connection: 1/8″ FNPT (female NPT) for easy integration into existing piping or tubing systems
- 4″ dial face for clear, easy-to-read pressure indication at a glance
- Two independently adjustable set-point pointers allow high and low limit switching without interrupting system operation
- Optical switch actuation provides reliable, repeatable switching with no mechanical contact wear
- Suitable for air and compatible non-combustible, non-corrosive gases
- Ideal for filter status monitoring, fan/blower control, clean room pressure management, and HVAC duct pressure applications
Specifications
- Brand: Dwyer Instruments
- Model / SKU: A3002
- Pressure Range: 0–2.0″ W.C.
- Process Connection: 1/8″ FNPT
- Dial Face Size: 4″
- Switch Type: Dual SPDT (High & Low set points)
- Switch Actuation: Photohelic optical switching
- Media: Air and compatible non-combustible, non-corrosive gases
Applications
- HVAC air filter differential pressure monitoring and change alerts
- Fan and blower performance verification
- Duct static pressure control and alarming
- Clean room and laboratory pressure management
- Industrial process pressure monitoring with switch output







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