Series-A3000

Supported Applications

The Series A3000 Photohelic® Switch/Gage is a versatile 2-in-1 instrument that combines the time-proven Magnehelic® differential pressure gage with low/high pressure switches. It measures and controls positive, negative, or differential pressure of air and other non-combustible, compatible gases, and the gage reading is unaffected by switch operation.

Because switch set points are adjusted with knobs on the face and the housing is molded from clear polycarbonate plastic, the series is well suited to filter monitoring, fan and blower control, cleanroom and HVAC pressurization, and general process pressure alarm or shutdown duties. On dual-scale air velocity (AV) models the instrument can also be used with a pitot tube to read air velocity in FPM. The Photohelic switch/gage may be used in an Underwriters Laboratories approved industrial control panel when the usage conforms to UL specifications for the acceptance of unlisted components.

Operating Conditions & Performance

The gage provides an accuracy of ±2% of full scale, with ±3% on -0 models and ±4% on -00 models. Switch repeatability is ±1% of full scale, and the dead band between make and break is 1% of full scale or less.

• Temperature limits: -6.67 to 48.9°C, with a low temperature option available.
• Pressure limits: standard models rated to 25 psig; the MP option extends this to 35 psig and the HP option to 80 psig.
• Switch type: each set point has two Form C relays (DPDT).
• Electrical rating: 10 A @ 28 VDC, 10 A @ 120, 240 VAC.
• Power requirements: 120 VAC, 50/60 Hz; 240 VAC and 24 VAC power optional.
• Process connection: 1/8" female NPT.

Screw terminals are used for electrical connections, and the instructions specify 75°C copper conductors only. The instrument presents a 101.6 mm dial face with a 127 mm outside diameter and an 8-1/4" overall dimension, and it weighs 4 lb (1.81 kg). The diaphragm must be mounted in the vertical position; consult factory for other orientations. Compliance is declared to CE, CSA, and UL.

Configuration Options

Models differ chiefly by pressure range, engineering unit, and switching options. Ranges are offered in several unit families so the gage face can be matched directly to the application:

• Inches of water column and zero-center inches of water ranges for low-pressure air work.
• Millimeters and centimeters of water ranges for metric low-pressure work.
• Pascal ranges from 0-60 Pa to 0-750 Pa, and kilopascal ranges from 0-1 kPa to 0-30 kPa.
• Dual-scale air velocity (AV) models that read both differential pressure and air velocity in FPM when used with a pitot tube.

Switching behavior is configurable through factory circuit styles and ordering options: single-relay activation on increase or decrease, medium- and high-pressure builds, tamper-proof knobs, and remote mounted relays.

Key Product Differences

Models are ordered as A3000-<RANGE> with optional suffixes (for example, A3000-00, A3000-6MM, A3000-1KPA, A3000-60PA). The following suffixes tailor the build:

• -HP — High pressure.
• -LT — Low temperature (-20°F).
• -MP — Medium pressure.
• -NIST — NIST traceable calibration certificate.
• -OLS — OEM model.
• -RMR — Remote mounted relay.
• -SRH — Single relay activates on increase.
• -SRL — Single relay activates on decrease.
• -TAMP — Tamper proof knobs.

Two accessories complete the range: the A-298 flat flush mounting bracket and the A-601 manual reset switch net.