Description
Dwyer 1638-2 Large Diaphragm Pressure Switch Overview
The Dwyer 1638-2 is a large diaphragm pressure switch engineered for reliable differential pressure sensing in HVAC, building automation, and light industrial applications. Designed to work with air and non-combustible gases, this switch delivers precise, repeatable switching performance across a 1″ to 3″ w.c. setpoint range — making it ideal for monitoring duct static pressure, filter status, fan operation, and airflow proving in commercial and residential systems.
Key Features
- Large diaphragm design for enhanced sensitivity and accurate low-pressure detection
- Setpoint range: 1″ w.c. to 3″ w.c.
- Approximate deadband: 0.06″ to 0.08″ w.c. for stable, chatter-free switching
- SPDT (Single-Pole, Double-Throw) switch for versatile NO/NC wiring configurations
- 1/8″ Female NPT pressure port connection for easy installation
- Compatible with air and non-combustible gases
Specifications
- Brand: Dwyer Instruments
- Model / SKU: 1638-2
- Pressure Range: 1″ w.c. to 3″ w.c.
- Approximate Deadband: 0.06″ – 0.08″ w.c.
- Switch Type: SPDT (Single-Pole, Double-Throw)
- Port Connection: 1/8″ Female NPT
- Sensing Element: Large Diaphragm
- Media: Air and Non-Combustible Gases
Typical Applications
- Duct static pressure monitoring
- Air filter differential pressure indication
- Fan and blower airflow proving
- HVAC building automation and control systems
- Ventilation system safety interlocks
Why Choose the Dwyer 1638-2?
Dwyer’s Series 1638 pressure switches are trusted across the HVAC industry for their durability, ease of installation, and consistent performance. The large diaphragm sensing element ensures accurate response at low differential pressures, while the SPDT output provides wiring flexibility for a wide range of control panel and DDC integration scenarios. The 1/8″ FNPT port simplifies field installation with standard fittings.
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