Series HM35 Precision Digital Pressure Manometer

Series HM35 Precision Digital Pressure Manometer

Series 477B Front View

Series 477B Handheld Digital Manometer

Series 490A Hydronic Differential Pressure Manometer

Liquid & Gas Pressure Measurement, ±0.5% FS Accuracy

The Series 490A Hydronic Differential Pressure Manometers are versatile, handheld, battery operated manometers available in several basic ranges for positive or positive differential pressure measurement and can tolerate most liquid media compatible with 316LSS. A new feature added to the Series 490A is a field adjustable damping, which allows the user to choose the level of display averaging rate corresponding to the fluctuation level common in many applications.

NEW! 490A-HKIT Option is located in the Product Configurator.

Hydronic meter kit includes: (2) six foot high-pressure rated tubing with shut off valves, high pressure 3-way valve, 8 ft poly tubing for purges, hard travel case, handheld carrying strap, 1/16" x 1 1/2", 1/8" x 3" and 1/8" x 1-1/2" pairs of pressure probes, 90° Flare to 1/4" NPT fittings, adjustable 8" wrench, PTFE Tape, and magnetic protective rubber boot. NIST Calibration Certificate comes standard.

California Residents:  Click Here for Proposition 65 WARNING.

Product Applications

  • Chiller to coils for freeze protection
  • Hydronic valve balancing
  • Measure pressure drop across pumps
  • Refrigerant pressure testing
Starting at $1,004.65
Grouped product items
Model Description Availability* Qty Price
490A-1 Wet/Wet handheld digital manometer, 0 to 15 psi (0 to 103.4 kPa) 2-3 Weeks*
490A-2 Wet/Wet handheld digital manometer, 0 to 30 psi (0 to 206.9 kPa) 2-3 Weeks*
490A-3 Wet/Wet handheld digital manometer, 0 to 50 psi (0 to 344.8 kPa) 2-3 Weeks*
490A-4 Wet/Wet handheld digital manometer, 0 to 100 psi (0 to 689.5 kPa) 2-3 Weeks*
490A-5 Wet/Wet handheld digital manometer, 0 to 500 psi (0 to 3448 kPa) 2-3 Weeks*
490A-6 Wet/Wet handheld digital manometer, 0 to 200 psi (0 to 1379 kPa) 2-3 Weeks*


Compatible gases & liquids.
Wetted Materials:
Without valve: 316L SS, -3V option: 316LSS, Buna-N, silicone, grease, PTFE, brass 360, copper, reinforced acetal copolymer.
±0.5% FS, 60 to 78°F (15.6 to 25.6°C); ±1.5% FS 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% FS.
Pressure Limits:
See chart on catalog page.
Electronic Temperature Limits:
32 to 140°F (0 to 60°C).
Storage Temperature Limits:
-4 to 176°F (-20 to 80°C).
0.42" (10.6 mm) 4 digit LCD.
See chart on catalog page.
Power Requirements:
9 V alkaline battery, installed non-functional, user replaceable.
Process Connections:
Two 1/8" (3.18 mm) female NPT.
14.1 oz (400 g).
Agency Approvals:


  • Seven user-selectable English and metric units
  • Stores up to 40 readings for later recall
  • Backlight for use in dim areas
  • Digital dampening for low pressure - high resolution logging accuracy
  • Automatic resolution adjustment for finer control

Product Literature


Catalog Pages

Product Data Sheet


Model Chart

EXAMPLE 490A 1 AT Series 490A-1-AT Wet/Wet Handheld Digital Manometer, range 0-15.00 psi, with aluminum tag.
SERIES 490A     Wet/Wet Handheld Digital Manometer
  0-15.00 psi
0-30.00 psi
0-50.00 psi
0-100.0 psi
0-500.0 psi
0-200.0 psi
Aluminum Tag
Certificate of Calibration
Factory Calibration Certificate
NIST Traceable Calibration Certificate
Stainless Steel Tag
3-Way Valve with Bleed Screw (100 psi max


Can a Slack tube manometer be used for water pressure?
That style of manometer is to be used with air/gases only. If you need something that reads water pressure, you would want to use something like our Series 490, Series 490A or Series 1211/1212.
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Model Description Availability* Price
A-47X-BOOT Rubber boot for manometers (manometer not included) 1-3 days*
A-HKIT-500XL Pressure test plug adapter for the 490A-HKIT, 1/8˝ dia x 3˝ length (2 per kit) 1-2 Weeks*
A-HKIT-AFIT Adapter kit, includes pairs of SAE 1/4" adapters and elbow fittings. 1-2 Weeks*
A-HKIT-500 Pressure test plug adapter for the 490A-HKIT, 1/8" dia x 1-1/2" length (2) 1-2 Weeks*
A-HKIT-HOSES One pair red & blue 60" SAE replacement hoses for the 490A-HKIT, each with integral ball valve 1-2 Weeks*
A-HKIT-BFIT Adapter fitting kit, includes pair of bleed fitting assemblies. 1-2 Weeks*
A-HKIT-510 Pressure test plug adapter for the 490A-HKIT, 1/16˝ dia x 1-1/2˝ length (2 per kit) 1-2 Weeks*
A-402A Carrying case for most manometers; tough, gray nylon pouch, double zippered with belt loop 1-3 days*