1640-2

1640-2 is a series 1640 floating contact null switch for high and low actuation. The Dwyer® Model 1640 differential pressure switch resembles the high precision large diaphragm series 1630 switches. However, the Model 1640 is equipped with a single pole, double throw floating contact switch (not snap acting) so it functions as a null switch. As the diaphragm moves in response to pressure changes, it moves the floating contact to cause switching action at two preset points with no switching action between these points. The “high” circuit will be closed when rising pressure differential reaches the preset level. The “low” circuit will be closed when falling pressure differential reaches the preset level. Typical applications include damper positioning and duct air control.

• Range 1.0-4.0" w.c.
• Adjustable null span, minimum set point is .03, maximum set point is .12
• Floating null switch supports applications requiring 2 set point actions(open, close damper control)
• Visible set point indicator simplifies operation and trouble shooting
• Large diaphragm provides low range accuracy providing precise control
• Temperature limit range from -30 to 110°F (-34.4 to 43.3°C)
• Pressure limit of 10psig (68.95kPa) continuous, 25psig (172.4kPa) surge
• 3 screw type electrical connection
• 1/8" female NPT process connection
• Diaphragm in vertical position