The Dwyer 1920-20 is the threaded-back-connection version of the Series 1900, with the high and low pressure ports relocated from the side to the back of the housing. This variant is preferred in tight installations where side clearance is limited or where flush panel mounting is required. It covers a setpoint range of 4.0-20.0 in WC, switches 15 A at 120-480 VAC through an SPDT relay, and is built around Dwyer's force-motion amplifier mechanism for repeatable trip performance (+/-3%) at very low actuating pressures. Service is air and other non-combustible, compatible gases only.
WARRANTY
Key Features
Force-Motion Amplifier Mechanism
Dwyer-engineered internal linkage amplifies diaphragm motion, giving the snap switch more travel per unit of pressure change. Result: +/-3% repeatability even at actuating pressures as low as 0.07 in WC.
15 A Switch Rating
SPDT snap switch is rated 15 A at 120-480 VAC, 60 Hz - significantly heavier duty than typical HVAC pilot relays. Drive small motors, contactors, or alarm circuits directly without an interposing relay. Derate to 10 A for high cycle rates.
Threaded Back Connections
High and low pressure ports relocated from the side of the housing to the back, allowing flush panel mounting and zero side clearance. Both ports remain 1/8 in female NPT for compatibility with standard fittings and accessories.
One-Side Installation
Pressure ports, electrical conduit, and setpoint adjustment are all located on the same side of the housing. The switch can be installed in corners or tight spaces where a conventional pressure switch with rear connections will not fit.
Wide Service Envelope
Operating temperature -30 to 180 F (32 F minimum for non-dry air), 80% RH non-condensing, up to 6,560 ft altitude. Continuous overpressure rated 45 in WC, 10 psig surge - tolerant of typical HVAC transients.
UL/CSA/FM/CE Listed
Series 1910 and 1920 carry multi-agency approvals: UL listed, CSA certified, FM approved, and CE marked. Installation category III (transient overvoltage); pollution degree 2. Ready for use in code-listed control panels.
Technical Specifications
| Specification | Value |
|---|---|
| Model | 1920-20 |
| Operating Range | 4.0-20.0 in WC |
| Approx. Deadband at Min. Setpoint | 0.40 in WC |
| Approx. Deadband at Max. Setpoint | 0.50 in WC |
| Service | Air and non-combustible, compatible gases (not for natural gas or other combustibles) |
| Wetted Materials | Consult factory |
| Switch Type | 1 Form C relay, SPDT |
| Electrical Rating | 15 A @ 120-480 VAC, 60 Hz; resistive 1/8 HP @ 125 VAC, 1/4 HP @ 250 VAC, 60 Hz. Derate to 10 A for high cycle rates. |
| Repeatability | +/- 3% |
| Electrical Connections | 3 screw-type terminals: common (COM), normally open (NO), normally closed (NC) |
| Installation Category | III (transient overvoltage) |
| Pollution Degree | 2 |
| Process Connections | 1/8 in female NPT, threaded back connections (high and low) |
| Enclosure | Standard conduit enclosure with snap-on cover (7/8 in conduit connection) |
| Temperature Limits, Operating | -30 to 180 F (-34 to 82.2 C); 32 F minimum for non-dry air |
| Humidity Limit | 80% RH, non-condensing |
| Altitude Limit | 6,560 ft (2,000 m) max |
| Pressure Limit, Continuous | 45 in WC (11.2 kPa) |
| Pressure Limit, Surge | 10 psig (68.95 kPa) |
| Mounting Orientation | Diaphragm in vertical plane |
| Setpoint Adjustment | Slotted screw inside conduit enclosure (tamper-resistant) |
| Weight | 1 lb 4.5 oz (581 g) |
| Compliance | CE, UL, CSA, FM |
| Manufacturer Part Number | 1920-20 |
Documentation
Frequently Asked Questions
What pressure range does the 1920-20 cover?
Can the 1920-20 be used outdoors or in cold environments?
Is the 1920-20 rated for natural gas or other combustible gases?
What's the difference between the 1920-20 and the 1910-20?
What is the Dwyer force-motion amplifier and why does it matter?
How do I wire the snap switch?
- Brand:
- Dwyer
- Series:
- 1900
- Sub-Family:
- 1920
- Product Type:
- Compact Differential Pressure Switch (Threaded Back Connections)
- Operating Range:
- 4.0-20.0 in WC
- Range Code:
- -20
- Deadband at Min Setpoint:
- 0.40 in WC
- Deadband at Max Setpoint:
- 0.50 in WC
- Service:
- Air, Noncombustible Gases (not natural gas)
- Switch Type:
- SPDT, 1 Form C Relay
- Reset Type:
- Automatic
- Electrical Rating:
- 15 A at 120-480 VAC, 60 Hz
- Repeatability:
- +/- 3%
- Process Connection:
- 1/8 in FNPT, Back
- Conduit Connection:
- 7/8 in (1/2 in NPT compatible)
- Conduit Enclosure:
- Standard, with snap-on cover
- Pressure Limit (Continuous):
- 45 in WC, 11.2 kPa
- Pressure Limit (Surge):
- 10 psig, 68.95 kPa
- Temperature Range:
- -30 to 180 F, -34 to 82.2 C (32 F min for non-dry air)
- Humidity Limit:
- 80% RH non-condensing
- Altitude Limit:
- 6,560 ft, 2,000 m
- Installation Category:
- III
- Pollution Degree:
- 2
- Mounting Orientation:
- Diaphragm Vertical
- Setpoint Adjustment:
- Slotted screw inside enclosure (tamper-resistant)
- Certifications:
- CE, UL, CSA, FM
- Weight:
- 1 lb 4.5 oz, 581 g
