Dwyer Magnehelic Gauge

Dwyer Magnehelic Gauges

  • For positive, negative or differential air pressure
  • Flush or surface mounted
  • Wide choice of ranges available

Gauge Connections: 1/8" NPT high and low pressure taps, duplicate one pair side and one pair back. Valves showing are extra.


  1. As an Air Filter Gauge measuring pressure drop across an air filter to indicate when filters need servicing.
  2. Sensing static pressure in an air system.
  3. Measuring air velocity in determining volume of flow.

Other magnehelic gauges are available in PSIG, KPA, and CM of water.

To sense static pressure For the most accurate measure of static pressure in an air stream, use a gauge connected to a static pressure tip such as DWYER Model A-301.

As a gauge to check air filters Gauge gives an instant visual indication when filters need servicing.

To determine flow

To measure air velocity (with optional pitot tube)

Air filter gauge package (A-605) Adapts any standard Magnehelic for use as an air filter gauge. Includes surface-mounting bracket, screws, 10 ft. tubing, two static pressure tips.

Vent Valves (A-310A)
Where pressure is continuous and the magnehelic gauge is connected by tubing which cannot be easily removed.
Gauge includes these mounting accessories:
two 1/8" SPT plugs, two 1/8" NPT to tube adapters, and flush mount adapters with screws.


Part # Range (in. w.c.)  
A-310A Vent Valve Call... Add to Order
A-432 Plastic Carrying Case Call... Add to Order
A-605 Air Filter Kit Call... Add to Order

Dwyer Magnehelic® Air Velocity Kit

Magnehelic® Air Velocity Kits contain gauge in plastic carrying case, with aluminum stand, two 1/8" NPT to rubber tubing adapters, 9 foot length of 3/16" tubing, and brass terminal tube.

Use with pitot tube (order separately) for air velocity measurement, or without pitot tube for pressure measurement. Magnehelic gauges are less sensitive to level than liquid, yet offer accuracy to ±2% over the full scale. Air Velocity Scale provides direct reading without conversions. They are handy to use on a ladder or in confined locations. Provides exceptionally responsive, consistently accurate indication of air velocity, positive, negative or differential pressures.

Dwyer Dual Range Air Balancing Kit

Our most popular precision air velocity instrument, the ABK400 is used to balance air conditioning systems, measure drop across filters, test fan and blower discharge and inlet pressure, as well as air velocity in ducts.

  • Measure both pressure and velocity
  • Read the red figures directly in f.p.m.
  • Read the black figures in inches W.C.
  • No conversion tables needed

A versatile, all around manometer for the air conditioning and air balancing contractor or industrial plant engineer.

Complete air velocity meter kit includes:

  • Inclined vertical manometer
  • Stainless steel calibrated pitot tube
  • Air velocity calculator slide rule
  • Two 9 ft. lengths of rubber tubing with connectors
  • Magnetic mounting clips
  • Additional gauge oil
  • Steel carrying case

Dwyer Air Velocity-Static Pressure Kit

Simplest, quickest to use air velocity instrument we know of. The AVK1000 Air Meter is very popular for service work or air conditioning, heating and ventilating equipment. Direct reading air velocity and static pressure scales — both high and low range — show supply and return grille velocities, duct air velocities, furnace draft, pressure drop across air filters, etc.

A Complete Pocket-Sized Kit!

Includes air meter, return and supply grille probes, angle connector, cleaning materials, instruction card, air velocity calculator, carrying case and one extra plastic ball in plastic tube.