Series 1640 Floating Contact Null Switch for High and Low Actuation

Visual Set Point Adjustment, Adjustable Null Zone

The unique electric switch design in the SERIES 1640 is another Dwyer Instrument, Inc. innovation. The Dwyer® Series 1640 Differential Pressure Switch resembles the Series 1630 switches. However, the Series 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.

A typical example of usage is to position motorized dampers when static pressure in a duct system reaches a desired maximum and reposition the dampers when the static pressure falls to a pre-established minimum. By using a Pitot tube sensing element the Series 1640 switch can serve in the same way to control air velocity and maintain a constant volume of air in a supply duct.

CAUTION: FOR USE ONLY WITH AIR OR COMPATIBLE GASES.

Product Applications

  • Damper positioning
  • Duct air control

Models & Ordering

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Model Description Usually Ships Price Order
1640-0
Ships: Next Day
Price: $404.00
Floating contact null switch, range .01-0.2" w.c., adj. null span, .01 min. set, .03 max. set. Next Day $404.00 Order
1640-1
Ships: Next Day
Price: $404.00
Floating contact null switch, range 0.2-1.0" w.c., adj. null span, .02 min. set, .06 max. set. Next Day $404.00 Order
1640-10
Ships: 1-2 Weeks
Price: $404.00
Floating contact null switch, range 3.0-12.0" w.c., adj. null span, .04 min. set, .20 max. set. 1-2 Weeks $404.00 Order
1640-2
Ships: Next Day
Price: $404.00
Floating contact null switch, range 1.0-4.0" w.c., adj. null span, .03 min. set, .12 max. set. Next Day $404.00 Order
1640-5
Ships: 1-2 Weeks
Price: $404.00
Floating contact null switch, range 2.0-6.0" w.c., adj. null span, .03 min. set, .18 max. set. 1-2 Weeks $404.00 Order

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Specifications

Service:
Air and non-combustible, compatible gases.
Wetted Materials:
Consult factory.
Temperature Limits:
-30 to 110°F (-34.4 to 43.3°C).
Pressure Limits:
10 psig (68.95 kPa) continuous, 25 psig (172.4 kPa) surge.
Switch Type:
SPDT.
Electrical Rating:
Non-inductive: 2.5 A @ 110 VAC, 1.5 A @ 220 VAC, 1 A @ 24 VDC, 0.5 A @ 110 VAC; Inductive: 1 A @ 110 VAC, 0.5 A @ 220 VAC, 0.5 A @ 24 VDC. (De-rate 70-80% for very slow pressure changes.)
Electrical Connections:
3 screw type, common, normally open and normally closed.
Process Connections:
1/8" female NPT.
Mounting Orientation:
Diaphragm in vertical position. Consult factory for other position orientations.
Set Point Adjustment:
Screw type.
Weight:
4 lb 13 oz (2.18 kg).
Agency Approvals:
CE.

Features

  • Floating “null” switch supports applications requiring two set point actions such as open and close damper control
  • Visible set point indicator simplifies operation and trouble shooting
  • Large diaphragm provides low range accuracy providing precise control

Options

  • -WP Weatherproof Housing.

Model Chart

EXAMPLE 1640 0 AT Series 1640-0-AT Floating Contact Null Switch for High and Low Actuation, range 0.01-0.2" w.c., with aluminum tag.
SERIES 1640     Floating Contact Null Switch for High and Low Actuation
RANGE   0
1
2
5
10
.25KPA
1KPA
1.5KPA
3KPA
  0.01 - 0.2" w.c.
0.20-1.0" w.c.
1.0-4.0" w.c.
2.0-6.0" w.c.
3.0-12.0" w.c.
0.05-0.25 kPa
0.4-1.0 kPa
0.5-1.5 kPa
1.0-3.0 kPa
OPTIONS     AT
LC
PRESET
ST
Aluminum Tag
Less Conduit
Preset
Stainless Steel Tag

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