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The Dwyer 1640-1 Floating Contact Null Switch for High and Low Actuation has a range from 0.2-1.0" w.c., adj. null span, .02 min. set, and .06 max. set.
The unique electric switch design in the 1640 is another Dwyer Instrument, Inc. innovation.The Dwyer® Model 1640 Differential Pressure Switch resembles the Series 1630 switches. The Model 1640, however, is equipped with a single pole, double throw floating contact switch (not snap acting) so it functions as a null switch.
Drawing shows the switching action schematically. 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 Model 1640 switch can serve in the same way to control air velocity and maintain a constant volume of air in a supply duct.
| Service | Air and non-combustible, compatible gases |
| 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 | Single-pole double throw (SPDT) floating contact (not snap action) |
| Process Connections | ?" (0.3175 cm) NPT |
| Electrical Rating | Non-inductive: 2.5 A at 110 V AC, 1.5 A at 220 V AC, 1 A at 24 V DC, 0.5 A at 110 V AC Inductive: 1 A at 110 V AC, 0.5 A at 220 V AC, 0.5 A at 24 V DC (De-rate 70 to 80% for very slow pressure changes) |
| Connections | Electrical: 3 screw type, common, normally open and normally closed Process: ?" female NPT |
| Mounting Orientation | Diaphragm in vertical position |
| Set Point Adjustment | Screw type |
| Agency Approvals | CE |
| Weight | 4 lbs (2.18 kg) |
All returns must be authorized. Items returned prior to authorization will not be accepted. For international customers where applicable, customers must ship any returns to us freight and duty prepaid. Return freight charges for internationsl shippments will be the responsibility of the customer.
Defective new equipment may be returned for warrantyrepair/exchange to us within (5) days of the shipment receipt date. After five (5) days, returns will be handled by direct contact and in accordance with the warranty terms of the item's manufacturer. Items that have malfunctioned due to mishandling, electrical overload, etc., will be subject to repair charge.
Non defective new equipment will be authorized for return within five (5) days of the shipment receipt date if the equipment is still in new, re-sellable condition with the original manual(s), accessories, packing material and carton. We reserve the right to reject returnsin which there is no original packaging, missing accessories, damage or visible signs of usage of the item. A restocking fee of up to 25% of purchase price may apply. Special orders and dangerous goods are non-returnable.
(Do not write anytingon the manufacturer's original package or use as a shipping carton. Include all accessories, manuals and warranties.)
Please, include a copy of the packing list or invoice with a reason for the return. Your return authorization number is valid for thirty (30) days.
We can ship to both US and Canada. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.
When you place an order, we will charge a flat rate shipping for your items.
Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.
Not Applicable
| Condition: | NA |
Defective new equipment may be returned for warrantyrepair/exchange to us within (5) days of the shipment receipt date. After five (5) days, returns will be handled by direct contact and in accordance with the warranty terms of the item's manufacturer. Items that have malfunctioned due to mishandling, electrical overload, etc., will be subject to repair charge.
Non defective new equipment will be authorized for return within five (5) days of the shipment receipt date if the equipment is still in new, re-sellable condition with the original manual(s), accessories, packing material and carton. We reserve the right to reject returnsin which there is no original packaging, missing accessories, damage or visible signs of usage of the item. A restocking fee of up to 25% of purchase price may apply. Special orders and dangerous goods are non-returnable.
(Do not write anytingon the manufacturer's original package or use as a shipping carton. Include all accessories, manuals and warranties.)
Please, include a copy of the packing list or invoice with a reason for the return. Your return authorization number is valid for thirty (30) days.
