Dwyer Instruments 1638-10 Pressure Switch

The Dwyer Instruments 1638-10 Pressure Switch is the commercial standard for high-precision monitoring of air and non-combustible gases. Engineered with a large diaphragm, this Series 1630 switch provides the low range accuracy required for critical HVAC duct air control and damper positioning applications. It operates within a 3" w.c. to 12" w.c. range with a 0.11-0.30 approximate deadband, ensuring a reliable differential pressure response across industrial service environments. The unit features an SPDT switch configuration with a 15A electrical rating at up to 480 VAC, allowing it to manage most small electrical loads directly without the need for additional relays. Constructed with a silicone rubber diaphragm and a zinc-plated steel housing, this adjustable pressure switch includes a visible set point indicator and a 1/8" female NPT process connection. For optimal performance and to maintain repetitive accuracy, the switch must be installed with the diaphragm in a vertical position.

• High-precision accuracy (±1% repeatability) for sensitive air conditioning and industrial pressure monitoring.
• Integrated visible set point indicator allows for immediate field verification and simplified calibration.
• Substantial 15 amp electrical capacity supports a wide range of direct-wired HVAC and process equipment.
• Robust silicone rubber diaphragm designed for long-term consistency in dry air or compatible gas service.
• Clear 1/8" female NPT ports ensure standard compatibility with existing pneumatic tubing and fittings.

Can the 1638-10 be mounted in any orientation?
No. To maintain stated accuracy and prevent set point drift, the 1638-10 must be mounted with the diaphragm in a vertical plane. Horizontal mounting can cause gravitational pull on the large diaphragm to alter the trip point.

What gases are compatible with this switch?
The Dwyer 1630 series is rated strictly for air and non-combustible, non-corrosive gases. It should not be used with combustible fuel gases or in hazardous environments unless installed in an approved explosion-proof housing.

How do I adjust the set point on this unit?
The set point is adjusted via an external screw that compresses the internal calibration spring. The current setting is easily read through the transparent scale enclosure on the side of the housing.

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Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.