Product Description
475-1-FM Intrinsically Safe Water-Column Digital Manometer for Classified Areas
The Series 475 Intrinsically Safe Handheld Digital Manometer – Model 475-1-FM is engineered for technicians working in flammable or regulated environments where low-pressure airflow and gas measurements must be performed safely. FM approved for Class I, Division 2 hazardous locations, this compact instrument measures positive, negative, and differential pressures in air and combustible gases while maintaining calibration-grade accuracy.
Produced by Dwyer Instruments, the Series 475 platform combines explosion-protection certification with rugged aluminum construction for boiler rooms, gas distribution systems, and industrial HVAC troubleshooting.
Hazardous-Area Certification & Safety Rating
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FM Approved: Intrinsically safe
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Classification: Class I, Div 2, Groups A, B, C, D
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Temperature Code: T4, Ta = 70 °C
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Agency Approvals: CE, FM
Pressure Measurement Capabilities
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Range: 0–20 in. w.c. (4.982 kPa)
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Maximum Pressure: 10 PSIG
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Accuracy: ±0.5% FS (60–78 °F)
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Positive / Negative / Differential modes
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Pressure hysteresis: ±0.1% FS
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Air-velocity measurement when paired with Pitot tube
Rugged Handheld Design for Field Service
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Protective aluminum enclosure
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Large easy-to-read LCD
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Dual-pad front controls for zero & unit selection
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Lightweight 10.8 oz form factor
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Barbed & compression tubing fittings
Hazardous-Location & HVAC Applications
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Natural-gas pressure testing on boilers
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Combustion-system diagnostics
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HVAC troubleshooting
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Field calibration of instruments
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Air-velocity surveys with Pitot tube
Environmental & Electrical Specifications
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Service: Air & combustible gases
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Operating Temp: 0–140 °F
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Compensated Range: 32–104 °F
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Power: 9 V alkaline battery
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Display: 4-digit LCD
