Dwyer 1900 User Manual [en, es]

Series 1900 Pressure Switch

4 [101.6] SQ.

7/8

[22.23]

3/4

[19.05]

3/4 [19.05]

4-3/4

[120.65]

5-1/2

[139.7]

HIGH PRESS.

CONN. 1/8 N.P.T.

LOW PRESS.

CONN. 1/8 N.P.T.

2 [50.8]

3 [76.2]

(4) 5-16 [7.94] DIA.
MTG. HOLES

WEATHERPROOF ELECTRIC

CONNECTION HUB

1/2⬙ NPT FEMALE

1-1/8

[28.58]

1-1/4 [31.75]

3/32

[2.38]

3 [76.2]

3-1 /8 [79.38]

2-3/4

Specifications - Installation and Operating Instructions

Series 1910 pressure switch. All
pressure and electrical connec­tions and set point adjustments
are on one side for easy installa­tion.

Advanced design and precision construction permit

these switches to perform many of the tasks of larger,
costlier units. Designed for air conditioning service, they
also serve many fluidics, refrigeration, oven and dryer
applications. For use with air and non-combustible gases.
Series 1900 switches are available with set points of 0.07
to 20 inches water column. Set point adjustment can be
made easily - before or after installation. Range screw is
inside conduit enclosure to help prevent tampering. For
easy mounting and access, pressure and electrical con­nections and set point adjustment are located on one
side. This permits installation in corners or spaces too
small for other switches.

SPECIAL MODELS & ACCESSORIES

Special close coupled street elbow for right angle pres­sure connections. Can be installed on switch anytime.
Zinc plated aluminum.

Weatherproof Housing

16 ga. steel enclosure with gasketed
cover (NEMA 4) for wet or oily condi­tions. Withstands 200 hour salt spray
test. Wt. 5 Ibs. (2.3 kg). Switch must
be factory installed. Change 1910
base number to 1911 and add -WP
suffix. Example: 1911-1-WP.

Explosion-Proof Housing

NEMA 7, 9 NEMA 3. (7 lbs). Switch
must be factory installed. Change
model to 1911 and add -EXPL suffix.
Example: 1911-1-EXPL. Aluminum
base and cover rated Class I, Groups
C & D, Div. 1. Class II, Groups E, F, &
G, Div. 1.

Series 1910 switch with conduit
enclosure off. Shows electric
switch and set point adjustment
screw.

6-1/2 [165.10]

CLEARANCE FOR

2X 6-1/8
[155.58]

COVER REMOVAL

4X Ø.281 [7.14]

1/8 FEMALE NPT
LOW PRESSURE CONNECTION

1/8 FEMALE NPT
HIGH PRESSURE CONNECTION

2X 4-1/4
[107.95]

6-5/8 [168.28]

1/2 NPT PROCESS
CONNECTION

3X 1-1/16

[26.99]

3 [76.20]

1/8 FEMALE NPT

41/64

[16.27]

HIGH PRESS.
CONNECTION

3

[76.20]

1-5/16

[33.32]

Ø3-1/2

TYP

[88.90]

Ø7/8 [22.23]
1-19/32
[40.48]

2-11/32
[59.53]

CONDUIT

CONNECTION

1-3/4 [44.45]

CLEARANCE
FOR COVER

REMOVAL

The Dwyer-engineered force-motion amplifier increases the
leverage of diaphragm movement and results in a switch with
excellent sensitivity and repeatability.

51/64

[20.24]

2-7/16 [61.90]

1-7/8

[47.63]

2-9/32
[57.94]

60 TYP

SPECIFICATIONS
Service: Air and non-combustible, compatible gases.
Wetted Materials: Consult Factory.
Temperature Limits: -30 to 180°F (-34 to 82.2°C) (32°F

for non dry air).
Pressure Limits: 45˝ 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: 1lb. 4.5 oz. (581 g).
Agency Approvals: CE, UL, CSA, FM.

ATEX: For ATEX compliant model change the Series Number
to 1911 and add a “-CN” suffix. These versions follow Directive
94/9/EC ATEX compliant for II 2 G EEx d IIB T6.

NOTE: For ATEX units wire in accordance with local electrical
codes. Cable should enter enclosure housing through an
approved EX cable gland (not supplied).

SERIES 1910 SWITCHES — MODELS

OPERATING

RANGES, DEADBANDS

Model

Number

1910-00
1910-0
1910-1
1910-5
1910-10
1910-20

Operating

Range,

Inches W.C.

0.07 to 0.15

0.15 to 0.55

0.40 to 1.6

1.40 to 5.5

3.0 to 11.75

4.0 to 20.0

Set Point

At Min.

0.04

0.10

0.15

0.30

0.40

0.40

Approximate

Dead Band

Bulletin E-56

(2) Ø3/16 [4.76]

MOUNTING HOLES

ON A 4-3/16 [106.36] B.C.

1/8 FEMALE NPT

LOW PRESSURE

CONNECTION

At Max.

Set Point

0.04

0.10

0.16

0.30

0.40

0.50

DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, IN 46361, U.S.A. Fax: [phone] e-mail: [e-mail]

Phone: [phone] www.dwyer-inst.com

INSTALLATION

Ø1/4 [6.350]

TYP

GROUND

SCREW

15/16 TYP

[23.81]

1-5/8

TYP

[41.28]

4-3/4 [120.65]
5-1/2 [139.70]

1-5/8

[41.28]
CLEARANCE
FOR COVER

REMOVAL

5-1/8

[130.18]

1-1/8

[28.58]

17/32

[13.49]

1-1/16

[26.97]

2-5/32

[54.76]

6-3/32

[154.78]

5-13/16
[147.64]

VENT

25/32

[19.83]

1/2 FEMALE NPT

CONDUIT CONNECTION TYP 2 PLACES

1/4 FEMALE NPT POSITIVE PRESSURE

1/4 FEMALE NPT NEGATIVE PRESSURE

1. Select a location that is free from excessive vibration,
corrosive atmosphere and where the ambient temperature
is within the limits for these switches.

2. Mount standard switches with the diaphragm in a vertical
plane and with switch lettering and nameplate in an upright
position. Some switches are position sensitive and may not
reset properly unless they are mounted with the diaphragm
vertical. (Special units can be furnished for other than verti­cal mounting arrangements if required.)

3. Connect switch to source of pressure, vacuum or differ­ential pressure. Metal tubing with 1/4˝ O.D. is recommend­ed, but any tubing which will not restrict the air flow can be
used. Connect to the two 1/8˝ female NPT pressure ports as
noted below:

• Differential pressures - connect pipes or tubes from source
of greater pressure to high pressure port marked HI-PR and
from source of lower pressure to low pressure port marked
LO-PR.

• Pressure only (above atmospheric) - connect tube from
source of pressure to high pressure port. The low pressure
port is left open to atmosphere.

• Vacuum only (below atmospheric pressure) - connect tube
from source of vacuum to low pressure port. The high pres­sure port is left open to atmosphere.

OPERATION

Pressure acting on the power diaphragm rotates the ampli­fying lever, which in turn extends the range spring and
rotates the snap switch input lever. When the set point is
reached, the snap switcch is actuated and the electrical con­tacts make or break.

ADJUSTMENT

To change the set point, proceed as follows:
A. Remove the snap-on cover from the conduit enclosure by
loosening its retaining screw and pulling firmly at its bottom
end. Turn the slotted adjustment screw at the top of range
spring housing clockwise to raise the set point pressure and
counter-clockwise to lower the set point.

B. The recommended procedure for calibrating or checking
calibration is to use a “T” assembly with three rubber tubing
leads, all as short as possible and the entire assembly offer­ing minimum flow restriction. Run one lead to the pressure
switch, another to the manometer of known accuracy and
appropriate range, and apply pressure through the third
tube. Make final approach to the set point very slowly. Note
that manometer and pressure switch will have different
response times due to different internal volumes, lengths of
tubing, fluid drainage etc. Be certain the switch is checked in
the position it will assume in use, i.e. with diaphragm in a
vertical plane and switch lettering and nameplate in an
upright position.

4. Electrical connections to the standard single pole, double
throw snap switch are provided by means of screw termi­nals marked “common”, “norm open”, and “norm closed”.
The normally open contacts close and the normally closed
contacts open when pressure increases beyond the set
point.

5. Switch loads should not exceed the maximum specified
current rating of 15 amps resistive. Switch capabilities
decrease with high load inductance or rapid cycle rates.
Whenever an application involves either of these factors,
the user may find it desireable to limit the switched current
to 10 amps or less in the interest of prolonging switch life.

ATEX Compliant Housing

Base number 1911 with -CN suffix.

C. For highly critical applicaitons it is a good idea to check
the set point adjustment and reset it as necessary once or
twice in the first few months of operation. This will compen­sate for any change in initial tension which may occur in the
spring and diaphragm. For most applications this change will
not be significant and no resetting will be required.

MAINTENANCE

Moving parts of these switches are sealed in and are per­manently tamper proof. The single adjustment is that of the
set point. Care should be taken to keep the switch reason­ably dry and free from dust or dirt. No lubrication or unusual
precautions are required for normal use.

DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, IN 46361, U.S.A. Fax: [phone] e-mail: [e-mail]

Phone: [phone] www.dwyer-inst.com