COVID-19 Update: Alpha Controls & Instrumentation is here to help and support your business in anyway possible during these uncertain times. Please click here to read more.


631B Capsuhelic® Wet/Wet Differential Pressure Transmitt...

Monitors differential pressure of air and compatible gases and liquids with accuracy, easily accessible zero and range adjustments

Starting At
$1,345.00 CAD
Normally ships in 2-3 Weeks

Configure   Request Quote

Can We Help You?


Our product experts are here to help you find the right solution for your application!

The Dwyer Series 631B Capsuhelic® Differential Pressure Transmitter monitors differential pressure of air and compatible gases and liquids with accuracy. The design employs converting pressure changes into a standard 4 - 20 mA output signal for two wire circuits. Digital push-button, zero and span adjustments are easily accessed on the front cover. The Series 631 Differential Pressure Transmitter is designed to meet NEMA 4X (IP66) construction. Robust housing offers 500 PSI static pressure rating on ranges down to 0.5 in W.C.

• Gage capsule permits high-pressure usage with small differentials
• Versatile device for liquid or gas supports designs requiring more precise measurements in support of application
• Zero and range adjustments outside of gage means no disassembly in normal service
• NEMA 4X rated enclosure provides protection in harsh environments permitting outdoor monitoring or in areas where dust and particulate matter exists


Service Compatible gases & liquids
Wetted Materials Brass, silicone, 300 SS
Accuracy Transmitter Output: ± 2% FS (includes linearity, hysteresis and repeatability).
Gage: ± 3% FS at 70°F (21.1°C)
Stability ± 1% FS/yr
Temperature Limits 20°F - 120°F (-6.67°C - 48.9°C)
Pressure Limits -20 inHg - 500 PSIG (0.677 Bar - 34.4 Bar)
Thermal Effect 0.025%/°F (0.045%/°C) includes zero & span
Power Requirements 10 VDC - 35 VDC
Output Signal 4 - 20 mA
Loop Resistance 0 Ω - 1250 Ω maximum
Electrical Connections M-12 circular 4 pin connector
Process Connections 1/4 in female NPT high and low pressure taps, duplicated - one pair top for air and gas, and one pair bottom for liquids
Enclosure Rating Designed to meet NEMA 4X (IP66)
Mounting Orientation Diaphragm in vertical position. Consult factory for other position orientations
Weight 8 lb 4 oz (3.74 kg)
Agency Approvals CE

• Refrigeration equipment
• Energy and water management
• Liquid level in water storage tanks