Contact Dwyer Sales Department: 1-201-419-6120  |

Series 475-FM Mark III Handheld Digital Manometer

Ranges from 1 in. w.c. to 150 psid, ±0.5% Accuracy.
New LOW Range Option 0-1.00 in. w.c.
Measures Positive, Negative and Differential Pressures
Rugged, Extruded Aluminum Case
Lightweight, Fast and Easy to Use
Dual Calibration with English and Metric Units
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 natural gases in ranges from 1 in. w.c. (0.249 kPa) to 150 psid (10.34 bar). The Series 475-FM is approved and is intrinsically safe for hazardous locations, Class 1, Div.1, Group A, B,C, D, T4. Its simple operation and easy to read digital display make it an indispensable test instrument for the plant engineer, industrial hygienist and HVAC technician. When used with a Dwyer Pitot tube (see Air Velocity), the Series 475 Mark III can also be used as an air velocity gage. See the complete 475-1-FM-AV kit described below.

The Series 475-FM 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. No setup or leveling. Zero adjust knob is conveniently located on top. The large 1/2" LCD display is easy to read, minimizing data collection errors. Units include a "low battery" indicator. The pressure sensor used is a highly stable silicon piezoresistive device. 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.

Service: Air and combustible, compatible gases.
Wetted Materials: Consult Factory.
Accuracy: ±0.5% F.S., 60 to 78°F (15.6 to 25.6°C); ±1.5% F.S. from 32 to 60°F and 78 to 104°F (0 to 15.6°C and 25.6 to 40°C).
Pressure Hysteresis: ±0.1% of full scale.
Pressure Limits: See Chart.
Temperature Limits: 0 to 140°F (-17.8 to 60°C).
Compensated Temperature Limits: 32 to 104°F (-0 to 40°C).
Storage Temperature Limits: -4 to 176°F (-20 to 80°C).
Display: 0.5" liquid crystal. 3-1/2 digits.
Resolution: See chart.
Power Requirements: 9 volt alkaline battery. Battery not connected.
Weight: 10.8 oz. (306 g).
Connections: Two barbed connections for use with 1/8" (3.18 mm) or 3/16" (4.76 mm) I.D. tubing. Two compression fittings for use with 1/8" (3.18 mm) I.D. x 3/16" (4.76 mm) O.D. tubing for 475-7-FM & 475-8-FM only.
Agency Approvals: FM, CE.
475-AV AIR VELOCITY KIT - Includes your choice of Series 475-FM Manometer, two A-303 static pressure tips, two 9 ft. lengths 3/16" I.D. rubber tubing, no. 166-6-CF Pitot tube, A-397 step drill, A-532 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 number.

A-402 CARRYING POUCH — Tough gray nylon pouch protects any Series 477 Manometer. Double zippered for quick and easy access. With belt loop that snaps closed. 72"H x 3"W x 24"D (191 x 76 x 57 mm)

Request Model A-402A

Popular Standard Models
Model Number English Range Metric Range Max. Pressure
 475-000-FM  0 - 1.00 in. w.c  0 - .249 kPa  10 in. w.c./2.5 kPa
 475-00-FM  0 - 4.00 in w.c.  0 to .995 kPa  5 psig/35 kPa
 475-0-FM  0 - 10.00 in. w.c.  0 - 2.49 kPa  5 psig/35 kPa
 475-1-FM  0 - 19.99 in. w.c.  0 - 4.97 kPa  10 psig/68.9 kPa
 475-2-FM  0 - 40.0 in. w.c.  0 - 9.95 kPa  10 psig/68.9 kPa
 475-3-FM  0 - 199.9 in. w.c.  0 - 49.7 kPa  30 psig/207 kPa
 475-4-FM  0 - 10.00 psid  0 - .689 bar  30 psig/207 bar
 475-5-FM  0 - 19.99 psid  0 - 1.378 bar  60 psig/4 bar
 475-6-FM  0 - 30.0 psid  0 - 2.07 bar  60 psig/4 bar
 475-7-FM  0 - 100 psid  0 - 6.89 bar  150 psig/10 bar
 475-8-FM  0 - 150 psid  0 - 10.34 bar  150 psig/10 bar
Popular Air Velocity Kit Models
Model Number Description
 475-000-FM-AV  Air Velocity Kit
 475-00-FM-AV  Air Velocity Kit
 475-0-FM-AV  Air Velocity Kit
 475-1-FM-AV  Air Velocity Kit