Product Overview
49
Differential Pressure Switches
PRESSURE
DWYER INSTRUMENTS, INC. | dwyer-inst.com
COMPACT LOW DIFFERENTIAL PRESSURE SWITCHES
Set Points from 0.07 to 20 in w.c. Repetitive Accuracy within 3%
Our most popular Series 1900 Compact Low Differential Pressure Switches
combine advanced design and precision construction to make these switches able
to perform many of the tasks of larger, costlier units. Designed for air conditioning
service, they also serve many uidics, refrigeration, oven and dryer applications.
Series 1900 switches have set points from 0.07 to 20 in w.c. (1.8 to 508 mm). Set point
adjustment is easy with range screw located inside conduit enclosure. Internal location
helps prevent tampering. UL, CE and CSA listed, and FM approved. For use with air
or compatible gages.
FEATURES/BENEFITS
• Compact size and repeatability, provides a high-value switch for many industrial and
OEM applications
• Wide range of models from 0.07 in w.c. to 20 in w.c. can meet exacting OEM
specications for a low pressure switch
• Range screw protected inside enclosure provides simplies making adjustments but
prevents tampering
APPLICATIONS
• Air conditioning refrigeration coil icing detection; defrost cycle initiation
• Clogged lter detection
• Variable air volume controller
41/64
[16.27]
1-19/32
[40.48]
2-11/32
[59.53]
Ø7/8 [22.23]
CONDUIT
CONNECTION
1-3/4 [44.45]
CLEARANCE
FOR COVER REMOVAL
3
[76.20]
Ø3-1/2
[88.90]
60° TYP
1/8 FEMALE NPT
HIGH PRESS. CONNECTION
1-5/16
[33.32]
TYP
2-7/16
[61.90]
2-9/32
[57.94]
1-7/8
[47.63]
(2) Ø3/16 [4.76]
MOUNTING HOLES
ON A 4-3/16 [106.36] B.C.
1/8 FEMALE NPT
LOW PRESSURE
CONNECTION
51/64
[20.24]
SPECIFICATIONS
Service: Air and non-combustible, compatible gases.
Wetted Materials: Consult factory.
Temperature Limits: -30 to 180°F (-34 to 82.2°C).
Pressure Limits: 45 in w.c. (11.2 kPa) continuous, 10 psig (68.95 kPa) surge.
Switch Type: Single-pole double-throw (SPDT).
Repeatability: ±3%.
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 operation at high cycle rates.
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 inside conduit enclosure.
Weight: 1 lb 4.5 oz (581 g).
Agency Approvals: CE, CSA, FM, and UL. Optional-EXPL explosion-proof
enclosure does not possess any agency approvals.
Series 1910 switch with conduit enclosure off.
Shows electric switch and set point adjustment screw located
on same side for easy installation.
Process Tubing Options: See page 453 (Gage Tubing Accessories)
The Dwyer-engineered force-motion amplier increases the leverage of
diaphragm movement and results in a switch with excellent sensitivity and repeatability.
Manual reset option
SERIES 1900
V
I
D
E
O
O
N
L
I
N
E
USA: California Proposition 65
WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov
OPTIONS
Weatherproof Housing
16 ga. steel enclosure with gasketed cover (NEMA 4, IP66) for wet or oily
conditions. Withstands 200 hour salt spray test. Wt. 5-1/2 Ib (2.5 kg). Switch must
be factory installed.
Note: To order, change 1910 base number to 1911, add -WP sufx.
Example: 1911-1-WP
Explosion-Proof Housing
Cast iron base with brass cover. Rated Class I, Groups D; Class II, Div. 2, Groups
E, F, G; Class III and NEMA 7, 9 NEMA 3. (7 lb). Switch must be factory installed.
Note: To order, change 1910 base number to 1911, add -EXPL sufx.
Example: 1911-1-EXPL
Manual Reset Option (Model 1900 MR)
Includes special snap switch which latches on pressure increase above the
setpoint. Switch must be manually reset after pressure drops below the setpoint.
Available on -1, -5,-10 or -20 ranges only. Option is not UL, CSA or FM listed. For
use only in single positive pressure applications.
Note: To order, change 1910 base number to 1900, add -MR sufx.
Example: 1900-10-MR
MODEL CHART
Model Operating Range in w.c.
Approximate Deadband
At Min. Set Point At Max. Set Point
1910-00
1910-0
1910-1
1910-5
1910-10
1910-20
0.07 to 0.15
0.15 to 0.5
0.40 to 1.6
1.40 to 5.5
3.0 to 11.75
4.0 to 20.0
0.04
0.10
0.15
0.30
0.40
0.40
0.04
0.10
0.16
0.30
0.40
0.50
ACCESSORIES
Model Description
A-399
A-329
A-302F-A
A-489
Duct pressure monitor kit; for use with standard or manual reset model
switches; includes mounting ange, tubing and adapters
Street ell; brass adapter for applications requiring right angle
connections; two required for differential pressures
303 SS static pressure tip with mounting ange; for 3/16˝ ID rubber or
plastic tubing; 4˝ insertion depth; includes mounting screws
4˝ straight static pressure tip with ange
Pressure_2021.indb 49 7/15/20 8:16 AM