Series-MARK-II-MPM

Supported Applications

The Dwyer Series MARK II Molded Plastic Manometers are inclined and inclined-vertical instruments designed for measuring differential pressure, static pressure, and air velocity. The series is intended for applications such as air filter gages and air velocity meters in HVAC systems. Both the Model 25 (inclined-vertical) and Model 40/41 (inclined) types support measurements above and below atmospheric pressure.

Operating Conditions & Performance

The series offers an accuracy of ±3% FS across its range configurations. Operating temperature limits vary by model type: the inclined-vertical models are rated to 140°F (60°C), while the inclined models are rated to 150°F (65°C). Pressure ratings differ accordingly, with a limit of 10 psi (70 kPa) for inclined-vertical units and 15 psi (100 kPa) for inclined units. Measurement ranges span from low differential pressures in inches water column (.10-0-1.00" w.c.) to air velocity scales up to 6300 fpm, as well as metric equivalents including Pascal (20-0-600 Pa) and millimeters of water column (0-80 mm w.c.).

Configuration Options

The series is configured with specific indicating fluids based on the model range. Models utilizing red fluid (.826 s.g.) include ranges such as 0-3 in w.c., 10-0-700 Pa, and air velocity scales up to 4200 fpm. Blue oil (1.91 s.g.) is specified for higher pressure or specific velocity models, including the 0-7 in w.c. range and velocities up to 6300 fpm.

Key configurable options and accessories include:

• Housing Types: Inclined-vertical (Model 25) with a curved tube for higher resolution at low readings, or inclined (Models 40/41) providing linear calibration throughout the range.
• Air Velocity Measurement: Models designated with "-AV" require an additional pitot tube to measure air velocity in fpm or mps.
• NIST Calibration: Variants are available with NIST traceable certification (e.g., MARK II 25-NIST).
• Mounting & Accessories: The series supports the A-612 Portable Stand, A-606 Air Filter Kit, and static pressure tips including the A-480 Plastic Static Pressure Tip and A-489 4" Straight Static Pressure Tip with Flange.
• Included Items: Standard kits include tubing connectors for 1/8" pipe or sheet metal ducts, mounting screws, indicating fluid (red or blue), pointer flags, and vinyl tubing where applicable.

Key Product Differences

The series distinguishes between two primary mechanical designs. The Model 25 is an inclined-vertical manometer with a curved tube; it measures up to 10 psi (70 kPa) and operates at ambient temperatures up to 140°F (60°C). It weighs approximately 1.04 lb (472 g).

The Model 40/41 series consists of inclined manometers with a linear scale length of approximately 8-1/4" (21 cm). These units support higher pressure limits up to 15 psi (100 kPa) and ambient temperatures up to 150°F (65°C), weighing approximately 1.23 lb (558 g).

Model numbering indicates the specific range and fluid type: codes ending in "-AV" denote air velocity capability requiring a pitot tube, while suffixes like "PA," "MM," or numeric ranges indicate Pascal, millimeter water column, or inch water column scales respectively.