The Dwyer 2025 is a 4 in dial differential pressure gage with a 0-25 in w.c. range, 2% of full scale accuracy and 1/8 in female NPT duplicate high and low pressure taps.
It uses Dwyer's frictionless Magnehelic movement: a silicone rubber diaphragm drives a flat spring-steel range spring carrying a samarium cobalt magnet, which rotates a helix in jeweled bearings to move the pointer with no mechanical linkages. The gage needs no external power and no manometer fluid. It indicates positive, negative (vacuum) or differential pressure of air and non-combustible, compatible gases.
Features
- Frictionless magnetic movement A samarium cobalt magnet rotates the helix without mechanical linkages, so the design resists shock, vibration and over-pressures.
- Reads at a distance A precision litho-printed scale behind an undistorted clear acrylic cover, with a red-tipped heat treated aluminium pointer rigidly mounted on the helix shaft.
- Weatherproof housing IP67 die cast aluminium case and bezel, iridite-dipped and finished in baked dark grey hammerloid to withstand a 168 hour salt spray corrosion test.
- Zero without opening the gage The zero adjustment screw sits in the cover and is reached without removing it; an O-ring seal maintains pressure tightness.
- Surface or flush mount from one case size One case size covers all standard pressure options. Flush mounting needs a 4-9/16 in diameter panel opening; surface mounting uses three No. 6-32 screws on a 4-1/8 in bolt circle.
- No manometer fluid The Magnehelic movement is dry, so there is no indicating fluid to service, and the gage movement itself needs no supply voltage or wiring.
- Overpressure relief plug A rubber blowout plug on the rear unseats and vents the gage interior at roughly 25 psig (1.72 bar). Rear spacer pads hold the relief path open when the gage is surface mounted; that gap must not be obstructed.
Applications
- Filter monitoring
- Air velocity with a Dwyer pitot tube
- Blower vacuum monitoring
- Fan pressure indication
- Duct, room or building pressures
- Clean room positive pressure indication
- Filter status monitoring in air handler units
- Filter monitoring in dust collectors
- Pressure monitoring of scrubber and fume exhaust systems
- Room pressure monitoring for hospital isolation rooms
Applications listed are those published by Dwyer for the Series 2000, in the catalog page and the Series 2000 product flyer. Dwyer specifies service for air and non-combustible, compatible gases.
Specifications
| Model / Part Number | 2025 |
|---|---|
| Range | 0-25 in w.c. |
| Dial Face | 4 in (101.6 mm) diameter |
| Minor Divisions | .50 |
| Accuracy | +/-2% of full scale throughout range at 70 F (21.1 C). The -HA high accuracy option improves this to +/-1% of full scale for this range. |
| Scale Position | Standard calibration; diaphragm in vertical position. |
| Service | Air and non-combustible, compatible gases. Natural gas option available. May be used with hydrogen when ordered with a Buna-N diaphragm at pressures below 35 psi. |
| Media Compatibility | Air and non-combustible, compatible gases. Consult factory to confirm compatibility with a specific gas before ordering. |
| Wetted Materials | Consult factory. |
| Housing | Die cast aluminium case and bezel with a clear acrylic cover. Exterior finish coated grey to withstand a 168 hour salt spray corrosion test. |
| Total Pressure Limit | -20 in Hg to 15 psig (-0.677 to 1.034 bar) |
| Overpressure | Relief plug opens at approximately 25 psig (1.72 bar). |
| Enclosure Rating | IP67 |
| Temperature Limits | 20 F (-6.67 C) to 140 F (60 C) |
| Dial Size | 4 in (101.6 mm) diameter dial face |
| Mounting Orientation | Diaphragm in vertical position. Consult factory for other orientations. |
| Panel Cutout (flush mount) | 4-9/16 in diameter |
| Process Connections | 1/8 in female NPT duplicate high and low pressure taps, one pair side and one pair back. |
| Weight | 1 lb 2 oz (510 g) |
| Standard Accessories | Two 1/8 in NPT plugs for duplicate pressure taps, two 1/8 in pipe thread to rubber tubing adapters and three flush mounting adapters with screws. |
| RoHS Compliance | Dwyer states that the Series 2000 meets the technical requirements of EU Directive 2011/65/EU (RoHS II). DwyerOmega also publishes a per-part certificate covering the later 2015/863 directive; use the compliance-status lookup in Documentation and confirm the certificate returned identifies this exact part number. |
| Design Origin | Designed in the USA using high quality components (Series 2000 product flyer). Dwyer does not publish a country of manufacture for this series, so no country of origin is claimed here. |
| Warranty | 5 Year Limited Warranty |
For applications with a high cycle rate within the gage total pressure rating, Dwyer recommends selecting the next higher pressure rating. See the medium (-MP) and high (-HP) pressure options.
Ordering Options
| -HA | High accuracy. Dwyer states +/-1% of full scale on standard +/-2% ranges, +/-1.5% on the -0, -100PA, -125PA and -10MM ranges, and +/-2% on the -00, -60PA and -6MM ranges. For this model the -HA figure is +/-1% of full scale. Includes a mirrored scale overlay and a six point calibration certificate. |
|---|---|
| -MP | Medium pressure, for pressures to 35 psig. |
| -HP | High pressure, for pressures to 80 psig. |
| -LT | Low temperature, to -20 F (-28 C). |
| -ASF | Adjustable signal flag, integral with the plastic gage cover. Not available on medium or high pressure construction. |
| -SP | LED set point indicator, 12-24 VDC. Ships with a medium pressure bezel and needs a 4-13/16 in flush mounting hole. Confirm RoHS status per part number using the DwyerOmega compliance-status lookup in Documentation. |
| -SS / -SB / -CB | Brushed 304 stainless, electropolished 304 stainless, or chrome plated bezel. |
| -M | Mirrored scale overlay, reduces parallax error. |
| -G / -R / -Y | Green, red or yellow transparent scale overlay. |
| -AHU1 / -AHU2 | Attached surface mounting plate; -AHU2 adds the A-481 installer kit. |
| -FC / -NIST | Factory calibration certificate, or NIST traceable calibration certificate. |
These are options published for the Series 2000 family. Not every option combines with every model or with the configuration on this page. Contact ZOT Supply to confirm a configured part number before ordering.
Accessories
| A-610 | Pipe mounting kit for 1-1/4 in to 2 in horizontal or vertical pipe. |
|---|---|
| A-605 / A-605B / A-605C | Air filter gage kits with static pressure tips, tubing and vent valves. |
| A-310A | 3-way vent valves, for permanently connected installations. |
| A-321 | Brass safety relief valve, opens at 10 psi. (DwyerOmega accessory listing.) |
| A-300 / A-368 / A-369 | Flush mounting bracket, surface mounting plate, stand-hang bracket. |
| A-464 / A-464-SS | Flush mount kit, steel or stainless steel. |
| A-286 | Gage panel mounting flange. |
| A-135 | Rubber gasket for panel mounting. |
| A-432 / A-401 | Portable carrying kit and plastic carry case. |
| A-448 | 3-piece magnet kit for mounting directly to a magnetic surface. |
| A-320 Series | Instrument enclosures in ABS or 304 stainless steel. |
A-610 pipe size is stated as 1-1/4 in to 2 in on the current Series 2000 catalog page and in Bulletin A-27. The superseded A-610 sheet (Bulletin A-38, 1989) states 1-1/2 in to 2 in. The current figure is used here.
Frequently Asked Questions
What is the pressure range of the Dwyer 2025?
The Dwyer 2025 is a standard Magnehelic differential pressure gage with a 0-25 in w.c. range and +/-2% of full scale accuracy at 70 F (21.1 C).
Does the Dwyer 2025 need power or wiring?
No. The Magnehelic movement is entirely mechanical, so the gage needs no supply voltage and no manometer fluid.
What is the maximum pressure the Dwyer 2025 can take?
The total pressure limit is -20 in Hg to 15 psig (-0.677 to 1.034 bar). A relief plug opens at approximately 25 psig (1.72 bar) on standard gages; it is a last-resort vent, not a system overpressure control.
What media can the Dwyer 2025 be used with?
Dwyer specifies air and non-combustible, compatible gases. A natural gas option is available, and the gage may be used with hydrogen when ordered with a Buna-N diaphragm at pressures below 35 psi.
What panel opening does the Dwyer 2025 need for flush mounting?
A 4-9/16 in diameter opening. Surface mounting instead uses three No. 6-32 machine screws spaced 120 degrees apart on a 4-1/8 in diameter bolt circle.
Is the Dwyer 2025 RoHS compliant?
Dwyer states that the Series 2000 meets the technical requirements of EU Directive 2011/65/EU (RoHS II). A DwyerOmega compliance-status lookup covering the later 2015/863 directive is in the Documentation section.
Documentation
- Series 2000 Catalog Page (specifications and model chart)
- Bulletin A-27 - Installation and Operating Instructions
- Bulletin A-27-HP-MP - Medium and High Pressure Option
- Bulletin A-28 - Air Filter Gage Instructions
- Bulletin A-38 - A-610 Pipe Mounting Kit Instructions
- Series 2000 Magnehelic Product Flyer
- DwyerOmega compliance-status lookup for 2025
Specification source. Range and accuracy for the 2025 are taken from the Dwyer Series 2000 catalog page (2000_1.pdf). Construction, pressure and temperature data are from Series 2000 catalog page 2000_1.pdf; Bulletin A-27 Rev. 6 (6/17). RoHS status is sourced separately from the DwyerOmega per-part compliance portal, linked above, rather than from the catalog alone. Data verified August 2026.
WARNING (California Proposition 65): This product can expose you to chemicals including lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.
- Pressure Type:
- Differential Pressure
- Series:
- 2000 Magnehelic
- Range Units:
- Inches of Water
- Full Scale Range:
- 0-25 in w.c.
- Scale Type:
- Standard
- Accuracy:
- +/-2% FS
- Process Connection:
- 1/8 in Female NPT
- Enclosure Rating:
- IP67
- Dial Size:
- 4 in
- Scale Position:
- Standard
