Handheld Digital Manometer

Series 475-FM Mark III


Ranges from 4 in. w.c. to 150 psid. ±0.5% Accuracy

Measures Positive, Negative and Differential Pressures

Rugged, Lightweight, Fast and Easy to Use

Dual Calibration with English and Metric Units

NEW! FM Approved


The Dwyer Series 475 Mark III Handheld Digital Manometer is ideal for field calibration, monitoring or trouble shooting HVAC systems, clean rooms or a wide range of other low pressure pneumatic systems. This handy instrument measures positive, negative or differential pressures of air and other non-corrosive, non-toxic gases. When used with a Dwyer Pitot tube (see Flow and Air Velocity), the Series 475 Mark III can also be used as an air velocity gage. See the complete 475-1-AV kit described below. Its simple operation and easy to read digital display make it an indispensable test instrument for the plant engineer, industrial hygienist and HVAC technician.

The Series 475 Mark III is housed in a durable extruded aluminum case with its solid state circuitry mounted on a tough fiberglass epoxy circuit board. A standard 9 volt battery provides up to 100 hours of operation. Dual push pads on the front panel control on-off operation and English or metric pressure unit selection - all with no set-up or leveling. Zero adjust knob is conveniently located on top. The large 1/2" LCD display is easy to read in even the poorest lighting conditions, minimizing data collection errors and it includes a "low battery" indicator. The pressure sensor used is a silicon piezo resistive device. The monolithic chip also has a laser trimmed resistor network to assure accurate, stable temperature compensation. Standard connections are dual sized for 1/8" or 3/16" I.D. vinyl or rubber tubing. Complete instructions are conveniently printed on rear of housing.





±0.5% of full scale, 60-78°F (15-25).

Pressure Hysteresis:


±0.1% of full scale.

Temperature Effect, Zero Reading:


0/5% of full scale, 32-122°F (0-50).

Operating Temperature Range:


32-122°F (0-50).

Maximum Pressure:


See Chart.

Power Source:


9 volt alkaline, included.

Pressure Connections:


Barbed for 1/8" or 3/16" I.D. tubing. 475-7-FM & 475-8-FM only; 1/8" or 3/16" O.D. tubing.

Battery Life:


Typically 100 hours.



0.5" liquid crystal.



6 9/16"H x 2 13/16"W x 29/32"D (166 x 71 x 23 cm).

Material (Float/Stem):


316 stainless steel.

Weight, Battery included:


12 ounces (340 grams)

Stocked   Models

Model Number

English Range

Metric Range

Maximum Pressure


0-4.00 in. w.c.
0-10.00 in. w.c.
0-19.99 in. w.c.
0-40.0 in. w.c.
0-199.9 in. w.c.
0-10.00 psid
0-19.99 psid
0-30.0 psid
0-100 psid
0-150 psid

0-.995 kPa
0-2.49 kPa
0-4.97 kPa
0-9.95 kPa
0-49.7 kPa
0-.689 bar
0-1.378 bar
0-2.07 bar
0-6.89 bar
0-10.34 bar

150 in. w.c./37 kPa
150 in. w.c./37 kPa
11 psig/75 kPa
11 psig/75 kPa
11 psig/75 kPa
58 psig/4 bar
58 psig/4 bar
58 psig/4 bar
150 psig/10 bar
150 psig/10 bar

475-AV Air Velocity Kit - Includes your choice of Series 475 Manometer, two A-303 static pressure tips, 2 ft. lengths 3/16" I.D. rubber tubing, no. 166-6-CF Pitot air velocity slide chart and instruction bulletin H-11, all packed in a tough, molded plastic carrying case with die cut foam liner. To order, add AV suffix to any standard 475 model no.

A-402-A Carrying Case - Tough gray nylon pouch protects any Series Manometer. Double zippered for quick and easy access. With belt loop that snaps closed.




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