Overview
The Dwyer A3015 Photohelic pressure switch is a 3-in-1 measurement and control instrument that functions as both a precise analog pressure gage and a highly repeatable pressure switch. This design uses infrared LED and phototransistor technology to measure and control positive, negative or differential pressures of air and compatible gases. The unit integrates a large, easy-to-read dial gage with the proven Magnehelic® design, eliminating the need for separate instruments in many applications.
Key Features
- 1% full scale dead band provides quick response to pressure changes with no switching delay or chatter
- Two Form C relays (DPDT) for each set point enable independent switching control
- Operating temperature range of 20–120°F (–6.67–48.9°C)
- Integral light shield prevents ambient light interference with the phototransistor in bright sunlight
- Dual set point adjustment knobs allow field calibration without tools
- Media: Clean dry air, inert gases, helium, nitrogen, and non-corrosive dry gases
Technical Specifications
- Pressure Range: 0–15″ w.c. (water column)
- Accuracy: ±2% of FS at 70°F (21.1°C)
- Supply Voltage: 120 VAC, 50–60 Hz; 240 VAC and 24 VAC power available as options
- Relay Configuration: Two Form C relays per set point, rated 10 A @ 28 VDC and 10 A @ 120/240 VAC
- Mounting: Panel mount with standard bezel
- Connection: Screw terminals for field wiring
Typical Applications
The Dwyer A3015 is ideal for HVAC systems, industrial air monitoring, filter maintenance alarms, fan pressure control, and process gas applications requiring dual set point switching. Its combination of visual indication and automatic control makes it suitable for applications where operators need both real-time pressure data and reliable automated switching at preset thresholds.
Compatibility & Replacements
Compatible With
- 24 VAC/VDC control circuits (with optional power supply)
- 240 VAC power supplies (optional configuration)
- HVAC systems and air handling units
- Industrial compressed air systems
- Clean air, inert gas, and non-corrosive gas media applications
Replaces / Drop-In Replacement For
- Series 3000 Photohelic models when upgrading to the newer A3000 series
- Older combination pressure gage and manual switch installations
- Verify compatibility with your current installation before ordering
Works With
- 120 VAC and optional 240 VAC / 24 VAC power supplies
- Electromechanical relay logic and PLC circuits requiring Form C dry-contact relays
- Standard industrial control panel designs and building management systems
- Field-adjustable set points for custom pressure thresholds
