Overview
Dwyer A3005 Photohelic Series 3000 combines a precision magnehelic pressure gage with two phototransistor-actuated DPDT relays in a single instrument. The Series A3000 Photohelic switches/gages function as versatile, highly repeatable pressure switches combined with a precise pressure gage, measuring and controlling positive, negative or differential pressures of air and compatible gases. Standard models are rated to 25 psig, with the A3005 specifically covering the 0-5″ W.C. range.
Key Features
- Two DPDT phototransistor-actuated relays for low/high limit control
- Easy-to-adjust set point indicators controlled by knobs located on the gage face
- Individual set point deadband is one pointer width—less than 1% of full scale
- Gage reading is continuous and unaffected by switch operation, even during loss of electrical power
- Optical limit switches used for reliability and long service life, with light shield protecting phototransistors from strong outside light sources
- CE, CSA, UL certified
Technical Specifications
- Pressure Range: 0 to 5.0 inches W.C.
- Accuracy: ±2% of full scale
- 120 VAC power, 50 to 60 Hz (240 and 24 VAC optional)
- Two Form C relays (DPDT) per setpoint
- Screw terminals, copper conductors rated to 167°F (75°C)
- Clear polycarbonate cover
- Suitable for air and non-combustible, compatible gases
Typical Applications
- HVAC system pressure monitoring and control
- Clean room differential pressure management
- Fume hood exhaust system control
- Laboratory and test equipment pressure regulation
- Furnace and boiler pressure switching
- Compressed air system monitoring
Compatibility & Replacements
Compatible With
- Standard 120 VAC electrical circuits (50-60 Hz)
- Optional 240 VAC and 24 VAC power configurations
- DPDT relay-compatible control circuits and PLC inputs
- Air and compatible non-combustible gases
Replaces / Drop-In Replacement For
- Dwyer A3000 Series units with identical 0-5″ W.C. range requirements
- Legacy Photohelic pressure switches requiring combined gage and relay functionality
Works With
- Standard 120 VAC facility power and control panels
- HVAC control systems and building automation networks
- PLC and industrial relay logic circuits via DPDT outputs
- Pneumatic damper and fan damper control systems
