Series-MP

Supported Applications

The Dwyer Series MP Mini-Photohelic® Differential Pressure Switch/Gage is designed to measure and control positive, negative, or differential pressures of non-combustible and non-corrosive gases. The unit combines a differential pressure gage with two SPDT switching setpoints, allowing the gage reading to remain independent of switch operation while providing visible LED indicators for switching status on both the front and rear.

Operating Conditions & Performance

The Series MP operates within an ambient temperature range of 20 to 120°F (-6.7 to 49°C). Accuracy is specified as ±5% of full scale @ 70°F (21.1°C) when the gage face is mounted in a vertical position; if used in any other orientation, re-zeroing is required each time the position changes. The device supports pressure limits up to 30 psig (2.067 bar). Standard process connections are provided via barbed fittings for 3/16" I.D. tubing, with an optional 1/8" male NPT connection available.

Configuration Options

The series offers a broad selection of measurement ranges to accommodate specific low-pressure requirements:

• Inches of Water Ranges: Models include MP-000 (0-0.5), MP-001 (0-1.0), MP-002 (0-2.0), MP-003 (0-3.0), MP-005 (0-5.0), MP-010 (0-10), and MP-020 (0-20).
• Pascal Ranges: Models include MP-125PA (0-125 Pa), MP-250PA (0-250 Pa), MP-500PA (0-500 Pa), and variants for 0-3 kPa.
• Metric Ranges: Models include MP-25MM, MP-50MM, and MP-100MM.

The unit features two SPDT relays with an electrical rating of 5A @ 120/240 VAC Resistive; 5A @ 30 VDC. Power requirements are 24 VDC / 24 VAC 50/60 Hz, consuming 4 watts. Electrical connections utilize a screw type terminal block accepting 22-12 AWG wire. Set points are adjusted via push-buttons located on the back of the unit.

Optional accessories include static pressure tips for various tubing types:

• A-301: Static pressure tip for 1/4" metal tubing connection
• A-302: Static pressure tip for 3/16" and 1/8" I.D. plastic or rubber tubing
• A-302F-A: 303 SS static pressure tip with mounting flange; for 3/16" ID rubber or plastic tubing; 4" insertion depth
• A-489: 4" straight static pressure tip with flange

Additional ordering options include a -NIST suffix for NIST traceable calibration certificate and a -NPT suffix for 1/8" male NPT connections. The unit measures 4-1/8" (104.78 mm) depth x 3-1/16" (77.79 mm) diameter and weighs 23 oz (652 g). Agency approvals include cULus and CE.

Key Product Differences

Variants within the Series MP are distinguished primarily by their measurement range, indicated in the model number suffix corresponding to inches of water, Pascals, or millimeters. The standard configuration includes barbed fittings for 3/16" I.D. tubing; models with the -NPT option feature 1/8" male NPT connections instead.