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Series 476A Single Pressure & Series 478A Digital Manometer

Single & Dual Pressure Measurement, Electronic Zeroing, ±1.5% Accuracy

Ideal for field or laboratory use, the Model 476A-0 Single Pressure Digital Manometer measures low pressures from -20 to 20" w.c. with ±1.5% full scale accuracy. Designed especially for the HVAC contractor, the Model 476A-0 can be used to set gas supply pressures, verify pressure switch operation, adjust regulators, check pneumatic systems and computer peripherals. The rugged, handheld unit is constructed with an extruded aluminum case for exceptional durability.

The Series 478A manometer can be used to measure positive, negative, or differential pressures. The unit features selectable units, auto zero, hold and a Min/Max function. Press the Hold key to freeze the current pressure measurement on the display. The 478A manometer includes a zeroing button to null out any minor pressure differences.

Product Applications

  • Verify field instrumentation performance
  • Adjust fuel mixture on combustion systems

Models & Ordering

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Model Description Usually Ships Price Order
Ships: Next Day>
Price: $59.95
Digital manometer, range -20 to 20" w.c. Next Day $59.95 Order

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Air and compatible gases.
Wetted Materials:
Consult factory.
±1.5% Full Scale @ 72°F (22.2°C). Includes linearity and repeatability.
Pressure Hysteresis:
±0.1% of Full Scale.
Pressure Limits:
5 psig (.34 bar).
Temperature Limits:
0 to 140°F (-17.8 to 60°C).
Compensated Temperature Limits:
32 to 104°F (0 to 40°C).
Thermal Effect:
0.05% F.S./°F.
4 digit LCD (.425"H x .234"W digits).
Power Requirements:
9 V alkaline battery, installed non-functional, user replaceable.
Process Connections:
Barbed connection for use with 3/16" or 1/4" I.D. tubing.
10.8 oz (306 g).
Agency Approvals:


  • One button auto-zero function
  • Auto power off function to conserve battery life
  • Rugged extruded aluminum housing
  • Instant selection of up to nine English/metric units
  • ±1.5% FS accuracy


Model Number Description Usually Ships Price Order
Rubber latex tubing has less tendency to kink in storage and occupies less
space, thus is best for portable work. 3/16 A-201 Rubber latex tubing has less tendency to kink in storage and occupies less space, thus is best for portable work. 3/16" ID, 9' length. Next Day $7.50 Order

Model Chart

Series 476A
EXAMPLE 476A 0 NIST Series 476A-0-NIST Single Pressure Digital Manometer, range -20.0 to 20.0" w.c.., with NIST certificate of calibration.
SERIES 476A     Single Pressure Digital Manometer
RANGE   0   -20.0 to 20.0" w.c.
OPTIONS     NIST NIST Certificate of Calibration

Series 478A
EXAMPLE 478A 0 NIST Series 478A-0-NIST Differential Pressure Digital Manometer, range -4.00 to 4.00" w.c.., with NIST certificate of calibration.
SERIES 478A     Differetnial Pressure Digital Manometer
  -4.00 to 4.00" w.c.
-60.0 to 60.0" w.c.
OPTIONS     NIST NIST Certificate of Calibration

Product Literature


Catalog Pages




My new Series 476A Digital Manometer scrolls through random numbers and letters like OFL after I tried to zero it. How do I fix it?
The 476A will continually display OFL if it has been over pressurized. Feel free to contact our customer service department to setup an RMA if you’d like it repaired.
How does a manometer measure gage and differential pressure?
Manometers simply measure the pressure by indicating the amount of displacement a liquid of known weight undergoes when a force is applied. This concept is best explained through illustrations in our Bulletin D-21 or in our Application Guides on how to use pressure products.
We use series 475-6-FM Mk III digital manometer. What is the recommended calibration interval?
We do not have an official recommended calibration interval. However, we would suggest checking the calibration at least once or twice a year depending on the applciation and how often the unit is used.
Is there a manometer that is compatible with chlorine gas and sodium hydroxide (bleach)?
Unfortunately, we do not have any manometers available that can handle chlorine gas or sodium hydroxide (bleach).

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