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

Shipping Information

All shipping times are dependent on product availability at time of shipment.

Although we make every effort to ensure a continuous supply of our products, occasional circumstances may force us to temporarily run out of a product, or have shipping delays. Should this occur, customers will be notified soon after placement of any orders for such products and, if applicable, items will be put on backorder. For orders requiring expedited shipment, our customer service team can be contacted to confirm product availability

COVID-19 Update: Due to high customer demand, lead time on some products may be up to two weeks. While this is a developing health situation, we are working continuously to take the necessary measures to ensure that the products you need are available with minimal interruption.

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Model	Description	Usually Ships*	Price	Order
1640-0 Ships: Same Day Price: $439.00	Floating contact null switch, range .01-0.2" w.c., adj. null span, .01 min. set, .03 max. set.	Same Day*	$439.00	Order
1640-1 Ships: 1-2 Weeks Price: $439.00	Floating contact null switch, range 0.2-1.0" w.c., adj. null span, .02 min. set, .06 max. set.	1-2 Weeks*	$439.00	Order
1640-10 Ships: 1-2 Weeks Price: $439.00	Floating contact null switch, range 3.0-12.0" w.c., adj. null span, .04 min. set, .20 max. set.	1-2 Weeks*	$439.00	Order
1640-2 Ships: 1-2 Weeks Price: $439.00	Floating contact null switch, range 1.0-4.0" w.c., adj. null span, .03 min. set, .12 max. set.	1-2 Weeks*	$439.00	Order
1640-5 Ships: 1-2 Weeks Price: $439.00	Floating contact null switch, range 2.0-6.0" w.c., adj. null span, .03 min. set, .18 max. set.	1-2 Weeks*	$439.00	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