The materials included in this compilation are for the use of Dwyer Instruments, Inc. potential customers and current employees as a resource only. They may not be reproduced, published, or transmitted electronically for commercial purposes. Furthermore, the Company’s name, likeness, product names, and logos, included within these compilations may not be used without specific, written prior permission from Dwyer Instruments, Inc. ©Copyright 2015 Dwyer Instruments, Inc.

1. Dwyer’s Handheld Digital
Manometers
The materials included in this compilation are for the use of Dwyer Instruments, Inc. potential customers and current employees as a
resource only. They may not be reproduced, published, or transmitted electronically for commercial purposes. Furthermore, the
Company’s name, likeness, product names, and logos, included within these compilations may not be used without specific, written prior
permission from Dwyer Instruments, Inc. ©Copyright 2015 Dwyer Instruments, Inc.

2. Outline
• Across the Board Features
• Manometer Selling Features and Competition
– 476A Single Pressure Manometer
– 478A, 475, 490A, 477B, 477AV differential
pressure manometers
• Applications
• Questions

3. Introduction
• Wide Selection
– Single Pressure
– Differential Pressure
– Air & Gas Measurement
– Wet/Wet Measurement
– High Accuracy

4. Across the Board Features
• 9 Volt Battery Powered
– Up to 100 Hours of Use
• Extruded Aluminum Case
• Ultra-fine Resolution on Low Ranges
• Selectable Units of Measure
• Includes Wrist Strap
• Instructions Printed on Device
• Carrying Cases, Air Flow Kits
and More Available

5. 476A & 478A Manometers
• Push Button Auto-Zero
• ±1.5% FS Accuracy
• Low Cost Design
• 476A: Single Pressure
– -20 to 20 in w.c.
• 478A: Differential Pressure
– -4 to 4 in w.c.
– -60 to 60 in w.c.

6. 475 Digital Manometer
• Vast Array of Ranges (11 total)
– Lowest Range: 0-1 in w.c.
– Highest Range: 0-150 psi
• ±0.5% FS accuracy
• Measures positive, negative &
differential pressures
• Air and compatible combustible gases
– Can be used for natural gases

7. 490A Hydronic Digital Manometer
• Liquid & Gas Pressure
• 316L SS Wetted Materials
• ±0.5% FS Accuracy
• Memory Function (stores 40 readings)
• Audible & Visual Overpressure Alarms
• Adjustable Dampening Rate
• Optional 3-Valve Manifold Block

8. 477B Digital Manometer
• Measure Positive, Negative, or Differential
Pressure
• Accuracy: 0.1% Full Scale
• Stores up to 40 Readings
• Audible and Visual Alarms
• Backlit Display
• Perfect for laboratory readings and checking
calibration of other instruments

9. 477AV Digital Manometer
• Pressure, Velocity, and Flow Measurements
– Programmable Duct Sizes
– Useful with Pitot Tubes
• Measures Positive, Negative, &
Differential Pressure
• Backlit Display
• Up to 40 stored readings
The
Traverse
Tool!

10. Manometer Accessories
• A-402A Carrying case
– Snaps on belt loop for easy carrying
• A-47X-BOOT Manometer Boot
– Extra protection for manometer
– Magnetic mounting on back

11. Clean Room Checks
• Verifies that the correct pressure
differential exists between the clean
room surrounding outside area
– Positively Pressurized: in case of leaks,
clean air leaks out instead dirty air and
germs leaking in
– Negatively Pressurized: In case of leaks,
clean air enters instead of the dirty air and
germs leaking out
Dwyer
478A, 475,
or 477B

12. Traverse Readings in Ducts
• Use with pitot tube or flow
sensor
• Measure air flow in ducts to
ensure proper system
performance
• 477AV calculates average
velocity and air flow
Dwyer
477AV

13. Gas Pressure Testing
• Checks natural gas input to furnaces, boilers, and
other gas-fired units
• Low pressure creates small, unsafe flame that cannot
combust all gas
• High pressure creates large, hot flame that can cause
overheating and warping
• Measure post-regulator and make adjustments
Dwyer
475

14. Filter Pressure Drop
• Measures the Difference Between the
Pressure Pre-filter and Post-filter
• Increase in Differential Pressure Indicates
Dirty Filter
Dwyer
478A or
475

15. Balancing Water Loops
• Measuring actual flow
compared to design flow to
optimize system performance
• Heating and cooling water
systems
• Unbalanced water flow in a
building causes higher
operating costs and comfort
issues
Dwyer
490A

16. Pressure Head Loss
• Energy lost from flowing fluid due to friction
– Major loss: pressure lost due to friction in pipes
– Minor loss: pressure lost due to tees, bends, valves,
obstructions
• Ensures proper flow to all areas of the water
system
Dwyer
490A

17. Verifying Calibration
• Compare pressure readings of other
instruments to highly-accurate 477B to verify
they are reading correctly
Dwyer
477B