Dwyer 2004D Magnehelic Differential Pressure Gauge

About Dwyer 2004D Magnehelic Differential Pressure Gauge

Dwyer 2004D Magnehelic Differential Pressure Gauge

Select the Magnehelic gage for high accuracy--guaranteed within 2% of full scale--and for the wide choice of 81 models available to suit your needs precisely. Using Dwyer's simple, frictionless Magnehelic gage movement, it quickly indicates low air or non-corrosive gas pressures--either positive, negative (vacuum) or differential. The design resists shock, vibration and over-pressures. No manometer fluid to evaporate, freeze or cause toxic or leveling problems. It's inexpensive, too. The Magnehelic gage is the industry standard to measure fan and blower pressures, filter resistance, air velocity, furnace draft, pressure drop across orifice plates, liquid levels with bubbler systems and pressures in fluid amplifier or fluidic systems. It also checks gas-air ratio controls and automatic valves, and monitors blood and respiratory pressures in medical care equipment.

Product Highlights

• Bezel provides flange for flush mounting in panel.
• Clear plastic face is highly resistant to breakage. Provides undistorted viewing of pointer and scale.
• Precision litho-printed scale is accurate and easy to read.
• Red tipped pointer of heat treated aluminum tubing is easy to see. It is rigidly mounted on the helix shaft.
• Pointer stops of molded rubber prevent pointer over-travel without damage.
• "Wishbone" assembly provides mounting for helix, helix bearings and pointer shaft.
• Jeweled bearings are shock-resistant mounted; provide virtually friction-free motion for helix. Motion damped with high viscosity silicone fluid.
• Zero adjustment screw is conveniently located in the plastic cover, and is accessible without removing the cover. O-ring seal provides pressure tightness.
• Helix is precision made from an alloy of high magnetic permeability. Mounted in jeweled bearings, it turns freely, following the magnetic field to move the pointer across the scale.
• Calibrated range spring is flat spring steel. Small amplitude of motion assures consistency and long life. It reacts to pressure on diaphragm. Live length adjustable for calibration.
• Silicone rubber diaphragm with integrally molded O-ring is supported by front and rear plates. It is locked and sealed in position with a sealing plate and retaining ring. Diaphragm motion is restricted to prevent damage due to overpressures.
• Die cast aluminum case is precision made and iridite-dipped to withstand 168 hour salt spray corrosion test.
• Exterior finished in baked dark gray hammerloid. One case size is used for all standard pressure options, and for both surface and flush mounting.

Overpressure Protection

Blowout plug is comprised of a rubber plug on the rear which functions as a relief valve by unseating and venting the gage interior when over pressure reaches approximately 25 PSIg (1.7 bar). To provide a free path for pressure relief, there are four spacer pads which maintain 0.023" clearance when gage is surface mounted. Do not obstruct the gap created by these pads. The blowout plug is not used on models above 180" of water pressure, medium or high pressure models, or on gages which require an elastomer other than silicone for the diaphragm. The blowout plug should not be used as a system overpressure control. High supply pressures may still cause the gage to fail due to over pressurization, resulting in property damage or serious injury. Good engineering practices should be utilized to prevent your system from exceeding the ratings or any component.

O-ring seal for cover assures pressure integrity of case. Samarium Cobalt magnet mounted at one end of range spring rotates helix without mechanical linkages.

• Range 0-4.0 in H2O
• 0-1.0 kPa

Robust Industrial Design

Constructed with a die-cast aluminum case and finished in matte, polished, or galvanized options, the Dwyer 2004D Magnehelic Gauge is suitable for harsh industrial environments. Its silicone rubber seal and acrylic dial offer resilience, ensuring longevity and reliability while monitoring air or non-corrosive gas pressures.


Accurate, Analog Display

With precision calibration and a clear 114 mm acrylic glass, this analog gauge provides precise differential pressure readings. The scale covers 0 to 250 Pa, while the 2% FS accuracy supports sensitive applications in HVAC, filtration, and process monitoring.


Flexible Mounting and User Convenience

The gauge can be mounted vertically either on a surface or flush, making installation adaptable. External zero adjustment via knob allows for on-site calibration, ensuring ongoing accuracy and ease of maintenance. All required mounting accessories are provided.