Dwyer A3005 Photohelic Pressure Switch 25 Psi 4 in Dial

Product Description

The DWYER A3005 is a Photohelic pressure switch and gauge combined into a single instrument designed for monitoring and control of differential or line pressure in HVAC, industrial, and air-handling systems. The unit features a 4-inch dial face for clear at-a-glance readings, a maximum operating pressure of 25 psi, and 2% full-scale accuracy. Connection is made through a 1/8-inch female NPT port. The polycarbonate plastic body keeps weight low while providing adequate resistance to typical mechanical room environments. A built-in low and high limit control relay function allows it to serve as both a gauge and a differential pressure switch without adding a separate control device to the circuit.

The A3005 is suited for residential and light commercial HVAC applications where differential pressure monitoring and switch action are required in one unit. Common install scenarios include supply and return duct static pressure monitoring, filter status indication, fan proving, and clean-room or laboratory pressure boundary verification. The instrument mounts via screw mount and is rated to 120 degrees F maximum ambient temperature. Its 5-inch water column range makes it well matched for low-pressure air-side applications common in forced-air systems.

Key Features

• Combined Photohelic gauge and pressure switch eliminates a separate control device
• 25 psi maximum operating pressure with 2% full-scale accuracy
• 4-inch dial face with integrated low and high limit control relays
• 1/8-inch female NPT connection for standard pipe thread hookup
• Polycarbonate plastic body construction — lightweight and corrosion resistant
• CE, CSA, and UL listed for use in code-required installations

Compatibility

Designed as an OEM-style replacement or direct-install Photohelic pressure switch and gauge for residential and commercial HVAC air-handling and duct pressure monitoring applications requiring 1/8-inch FNPT connections and low-pressure differential measurement.

Installation Notes

Installation is typically performed by a licensed HVAC technician or instrumentation technician familiar with low-pressure differential measurement circuits. Shut off the air-handling unit and relieve all system pressure before connecting or disconnecting pressure taps. Verify that control voltage wiring to the switch contacts conforms to NEC requirements for the specific circuit class. Do not exceed the 25 psi maximum operating pressure or the 120 degrees F maximum ambient temperature rating.