E-56 ATEX:E-56atex 2/11/10 10:04 AM Page 1

Bulletin E-56

Series 1900 Pressure Switch

Specifications - Installation and Operating Instructions

1/8 FEMALE NPT

HIGH PRESS. 60 TYP
CONNECTION

(2) Ø3/16 [4.76]

3 MOUNTING HOLES
[76.20] 1-5/16 ON A 4-3/16 [106.36] B.C.
Ø3-1/2 [33.32] 1/8 FEMALE NPT
[88.90] TYP LOW PRESSURE
CONNECTION

41/64 51/64
Ø7/8 [22.23] [20.24]
[16.27] 1-19/32 CONDUIT 1-7/8
[40.48] CONNECTION [47.63]
2-11/32 2-9/32
[59.53] 1-3/4 [44.45] [57.94]
CLEARANCE 2-7/16 [61.90]
FOR COVER
REMOVAL

Series 1910 pressure switch. All Series 1910 switch with conduit The Dwyer-engineered force-motion amplifier increases the
pressure and electrical connec- enclosure off. Shows electric leverage of diaphragm movement and results in a switch with
tions and set point adjustments switch and set point adjustment excellent sensitivity and repeatability.
are on one side for easy installa- screw.
tion.

Advanced design and precision construction permit SPECIFICATIONS

these switches to perform many of the tasks of larger, Service: Air and non-combustible, compatible gases.
costlier units. Designed for air conditioning service, they Wetted Materials: Consult Factory.
also serve many fluidics, refrigeration, oven and dryer Temperature Limits: -30 to 180°F (-34 to 82.2°C) (32°F
for non dry air).
applications. For use with air and non-combustible gases.
Pressure Limits: 45˝ w.c. (11.2 kPa) continuous, 10 psig
Series 1900 switches are available with set points of 0.07 ( 68.95 kPa) surge.
to 20 inches water column. Set point adjustment can be Switch Type: Single-pole double-throw (SPDT).
made easily - before or after installation. Range screw is Repeatability: ±3%.
inside conduit enclosure to help prevent tampering. For Electrical Rating: 15 A @ 120-480 VAC, 60 Hz. Resistive
easy mounting and access, pressure and electrical con- 1/8 HP @125 VAC, 1/4 HP @ 250 VAC, 60 Hz. Derate to
nections and set point adjustment are located on one 10 A for operation at high cycle rates.
side. This permits installation in corners or spaces too Electrical Connections: 3 screw type, common, normally
small for other switches. open and normally closed.
Process Connections: 1/8˝ female NPT.
SPECIAL MODELS & ACCESSORIES Mounting Orientation: Diaphragm in vertical position.
Consult factory for other position orientations.
Special close coupled street elbow for right angle pres-
Set Point Adjustment: Screw type inside conduit
sure connections. Can be installed on switch anytime. enclosure.
Zinc plated aluminum. 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
WEATHERPROOF ELECTRIC 1-1/8
Weatherproof Housing 7/8
4 [101.6] SQ. CONNECTION HUB
1/2⬙ NPT FEMALE
[28.58] 94/9/EC ATEX compliant for II 2 G EEx d IIB T6.
16 ga. steel enclosure with gasketed [22.23] (4) 5-16 [7.94] DIA.
MTG. HOLES
cover (NEMA 4) for wet or oily condi-
tions. Withstands 200 hour salt spray
NOTE: For ATEX units wire in accordance with local electrical
2 [50.8]

codes. Cable should enter enclosure housing through an

3 [76.2]

test. Wt. 5 Ibs. (2.3 kg). Switch must

be factory installed. Change 1910
base number to 1911 and add -WP approved EX cable gland (not supplied).
suffix. Example: 1911-1-WP. 3/4
[19.05] 3/4 [19.05]
3/32
4-3/4
[120.65] 5-1/2
HIGH PRESS. LOW
1-1/4 [31.75]
PRESS.
3 [76.2]
3-1/8 [79.38]
[2.38] SERIES 1910 SWITCHES — MODELS OPERATING
[139.7] CONN. 1/8 N.P.T. CONN. 1/8 N.P.T. 2-3/4 RANGES, DEADBANDS
6-1/2 [165.10]
CLEARANCE FOR 1/2 NPT PROCESS Approximate
4X Ø.281 [7.14]
COVER REMOVAL CONNECTION Operating Dead Band
Explosion-Proof Housing Model Range,
NEMA 7, 9 NEMA 3. (7 lbs). Switch
At Min. At Max.
must be factory installed. Change
2X 4-1/4
[107.95]
Number Inches W.C. Set Point Set Point
2X 6-1/8
model to 1911 and add -EXPL suffix. [155.58]
1910-00 0.07 to 0.15 0.04 0.04
Example: 1911-1-EXPL. Aluminum 3X 1-1/16

base and cover rated Class I, Groups 1/8 FEMALE NPT

[26.99]
1910-0 0.15 to 0.55 0.10 0.10
LOW PRESSURE CONNECTION
3 [76.20]
C & D, Div. 1. Class II, Groups E, F, & 1/8 FEMALE NPT
HIGH PRESSURE CONNECTION
6-5/8 [168.28]
1910-1 0.40 to 1.6 0.15 0.16
G, Div. 1. 1910-5 1.40 to 5.5 0.30 0.30
1910-10 3.0 to 11.75 0.40 0.40
1910-20 4.0 to 20.0 0.40 0.50

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E-56 ATEX:E-56atex 2/11/10 10:04 AM Page 2

INSTALLATION OPERATION
1. Select a location that is free from excessive vibration, Pressure acting on the power diaphragm rotates the ampli-
corrosive atmosphere and where the ambient temperature fying lever, which in turn extends the range spring and
is within the limits for these switches. rotates the snap switch input lever. When the set point is
reached, the snap switcch is actuated and the electrical con-
2. Mount standard switches with the diaphragm in a vertical tacts make or break.
plane and with switch lettering and nameplate in an upright
position. Some switches are position sensitive and may not ADJUSTMENT
reset properly unless they are mounted with the diaphragm To change the set point, proceed as follows:
vertical. (Special units can be furnished for other than verti- A. Remove the snap-on cover from the conduit enclosure by
cal mounting arrangements if required.) loosening its retaining screw and pulling firmly at its bottom
end. Turn the slotted adjustment screw at the top of range
3. Connect switch to source of pressure, vacuum or differ- spring housing clockwise to raise the set point pressure and
ential pressure. Metal tubing with 1/4˝ O.D. is recommend- counter-clockwise to lower the set point.
ed, but any tubing which will not restrict the air flow can be
used. Connect to the two 1/8˝ female NPT pressure ports as B. The recommended procedure for calibrating or checking
noted below: calibration is to use a “T” assembly with three rubber tubing
leads, all as short as possible and the entire assembly offer-
• Differential pressures - connect pipes or tubes from source ing minimum flow restriction. Run one lead to the pressure
of greater pressure to high pressure port marked HI-PR and switch, another to the manometer of known accuracy and
from source of lower pressure to low pressure port marked appropriate range, and apply pressure through the third
LO-PR. tube. Make final approach to the set point very slowly. Note
• Pressure only (above atmospheric) - connect tube from that manometer and pressure switch will have different
source of pressure to high pressure port. The low pressure response times due to different internal volumes, lengths of
port is left open to atmosphere. tubing, fluid drainage etc. Be certain the switch is checked in
• Vacuum only (below atmospheric pressure) - connect tube the position it will assume in use, i.e. with diaphragm in a
from source of vacuum to low pressure port. The high pres- vertical plane and switch lettering and nameplate in an
sure port is left open to atmosphere. upright position.

4. Electrical connections to the standard single pole, double C. For highly critical applicaitons it is a good idea to check
throw snap switch are provided by means of screw termi- the set point adjustment and reset it as necessary once or
nals marked “common”, “norm open”, and “norm closed”. twice in the first few months of operation. This will compen-
The normally open contacts close and the normally closed sate for any change in initial tension which may occur in the
contacts open when pressure increases beyond the set spring and diaphragm. For most applications this change will
point. not be significant and no resetting will be required.

5. Switch loads should not exceed the maximum specified MAINTENANCE

current rating of 15 amps resistive. Switch capabilities Moving parts of these switches are sealed in and are per-
decrease with high load inductance or rapid cycle rates. manently tamper proof. The single adjustment is that of the
Whenever an application involves either of these factors, set point. Care should be taken to keep the switch reason-
the user may find it desireable to limit the switched current ably dry and free from dust or dirt. No lubrication or unusual
to 10 amps or less in the interest of prolonging switch life. precautions are required for normal use.

1/2 FEMALE NPT

CONDUIT CONNECTION TYP 2 PLACES
25/32 1/4 FEMALE NPT POSITIVE PRESSURE
[19.83] Ø1/4 [6.350]
1/4 FEMALE NPT NEGATIVE PRESSURE TYP

GROUND
SCREW
VENT

5-13/16 6-3/32
[147.64] [154.78]

17/32 1-5/8 4-3/4 [120.65] 15/16 TYP

[13.49] 1-1/16 1-1/8 TYP [23.81]
[26.97] 1-5/8 [41.28] 5-1/2 [139.70]
[28.58]
2-5/32 [41.28]
[54.76] CLEARANCE
5-1/8 FOR COVER
[130.18] REMOVAL

ATEX Compliant Housing

Base number 1911 with -CN suffix.

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E-56 ATEX:E-56atex 2/11/10 10:04 AM Page 3

Bulletin E-56

Presostatos Serie 1900

Instrucciones de Montaje y Operación

1/8 FEMALE NPT

HIGH PRESS. 60 TYP
CONNECTION

(2) Ø3/16 [4.76]

3 MOUNTING HOLES
[76.20] 1-5/16 ON A 4-3/16 [106.36] B.C.
Ø3-1/2 [33.32] 1/8 FEMALE NPT
[88.90] TYP LOW PRESSURE
CONNECTION

41/64 51/64
Ø7/8 [22.23] [20.24]
[16.27] 1-19/32 CONDUIT 1-7/8
[40.48] CONNECTION [47.63]
2-11/32 2-9/32
[59.53] 1-3/4 [44.45] [57.94]
CLEARANCE 2-7/16 [61.90]
FOR COVER
REMOVAL

Series 1910 pressure switch. All Series 1910 switch with conduit The Dwyer-engineered force-motion amplifier increases the
pressure and electrical connec- enclosure off. Shows electric leverage of diaphragm movement and results in a switch with
tions and set point adjustments switch and set point adjustment excellent sensitivity and repeatability.
are on one side for easy installa- screw.
tion.

El diseno avanzado y la constucción prcisa permitne SPECIFICATIONS

que estospresostatos reemplacen a otros de mayor pre- Service: Air and non-combustible, compatible gases.
cio y tamaño. Sirven para uso en acondicionamiento de Wetted Materials: Consult factory.
aire, hornos, secaderos y aplicaciones en fluídica y refrig- Temperature Limits: -30 to 180°F (-34 to 82.2°C) (32°F
eración. Aptos para uso en aire y gases no combustibles. for non dry air).
Ranges disponibles desde 0.07˝ a 20˝ de C.A. Pressure Limits: 45˝ w.c. (11.2 kPa) continuous, 10 psig
( 68.95 kPa) surge.
El ajuste puede ser antes o después de instalado. El
Switch Type: Single-pole double-throw (SPDT).
tornillo de ajuste está oculto dentro de la cubierta de Repeatability: ±3%.
conexiones para evitar manipuleo indebido. El ajuste, las Electrical Rating: 15 A @ 120-480 VAC, 60 Hz. Resistive
conexiones de presión y elelctricas están de un solo lado 1/8 HP @125 VAC, 1/4 HP @ 250 VAC, 60 Hz. Derate to
para facilitar el montaje. Esto permite la instalación en rin- 10 A for operation at high cycle rates.
cones o lugares estrechos. Electrical Connections: 3 screw type, common, normally
open and normally closed.
MODELOS Y ACCESORIOS ESPECIALES Process Connections: 1/8˝ female NPT.
Accesorio Dwyer A-329 Mounting Orientation: Diaphragm in vertical position.
Consult factory for other position orientations.
Codo de conexión an ángulo recto. Puede instalarse en Set Point Adjustment: Screw type inside conduit
enclosure.
cualquier momento. Construcción en aluminio zincado.
Weight: 1lb. 4.5 oz. (581 g).
Agency Approvals: CE, UL, CSA, FM.

Gabinete Hermético WEATHERPROOF ELECTRIC 1-1/8

4 [101.6] SQ. CONNECTION HUB [28.58]
Gabinete de acero cal. #16 para am- 7/8 1/2⬙ NPT FEMALE
bientes extremadamente húmedos o [22.23] (4) 5-16 [7.94] DIA.
aceitosos. Peso 5 lb. Presóstato in- MTG. HOLES
stalado en fábrica. Especifique “WP”
2 [50.8]

más el nro. de modelo.

3 [76.2]

PRESOSTATOS SERIE 1910

3/4
[19.05] 3/4 [19.05] RANGOS Y BANDA MUERTA
4-3/4 1-1/4 [31.75] 3/32
5-1/2 3 [76.2] [2.38]
[120.65] HIGH PRESS. LOW PRESS. 3-1/8 [79.38] Banda Muerta
[139.7] CONN. 1/8 N.P.T. CONN. 1/8 N.P.T. 2-3/4
Modelo Rango Aj. Minimo Aj. Máximo
Gabinete Antiexplosivo 6-1/2 [165.10]
CLEARANCE FOR 1/2 NPT PROCESS
COVER REMOVAL CONNECTION
4X Ø.281 [7.14]
Base de hierro fundido y tapa en alu-
minio. Peso aprox. 5 lb. Especifique 1910-00 0,07 to 0,15 0,04 0,04
“EXPL” más el nro. de modelo. 2X 4-1/4
[107.95]
2X 6-1/8
1910-0 0,15 to 0,55 0,10 0,10
[155.58]
1910-1 0,40 to 1,6 0,15 0,16
3X 1-1/16
1/8 FEMALE NPT
[26.99] 1910-5 1,40 to 5,5 0,30 0,30
LOW PRESSURE CONNECTION
1/8 FEMALE NPT
3 [76.20]
6-5/8 [168.28]
1910-10 3,0 to 11,75 0,40 0,40
HIGH PRESSURE CONNECTION
1910-20 4,0 to 20,0 0,40 0,50

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E-56 ATEX:E-56atex 2/11/10 10:04 AM Page 4

INSTALACION
1. Elija un sitio donde no haya vibraciones excesivas, OPERACION
atmósfera corrosiva, y la temperatura se mantenga den- La presión actúa sobre el diafragma, girando la palanea
tro de los límites tolerados por el presóstato (vea las amplificadora. Esta a su vez, extiende el resorte
especificaciones). antagónico (de calibrasión) el que está mecánicamente
vinculado a la palanca actuadora del interruptor inversor:
2. Instale el presóstato con el diafragma en un plano ver- Al alcanzarse el valor preajustado, la condición de los
tical, y el Logo de DWYER y la escritura de la etiqueta contactos se invierte, es decir el NA pasa cerrado, y el
en la parte superior. Algunos instrumentos son sensibles NC pasa abierto.
a la posición y no conmutarian adequadamente si el
diafragma no está vertical. AJUSTE
Para cambiar el ajuste, proceda de la siguiente manera:
Si se requiere, se pueden suministrar unidades espe- A. Retire la tapa cubre-conexiones aflojando el tornillo de
ciales para montaje en distinte posición. retención, y tirando firmemente de su extremo inferior.
Gire el tornillo de ajuste en sentido horario para incre-
3. Conecte el presostato a proceso por medio de los mentar la presión de actuación, o bien gírelo en sentido
conectores hembra NPT de 1/8˝. Se recomienda para anti-horario para disminuir la misma.
esto., utilizar tubo metalico de 1/4˝ diam. ext. sin embar-
go puede usarse cualquier tubo que no retrinja el paso B. El procedimiento más seguro y simple para consequir
de aire. Recuerde que: una calibración correcta (o la verificación) del punto de
• Presión diferencial: Conecte la alta presion a HI-PR trabajo es la siguiente:
(alta presion) y la baja a LO-PR (baja presion). 1. Conecte una tubería de goma de poca longitud desde
• Presión: conecte la presión (superior a la atmosférica) el presóstato a una T de conexión, otra desde la T a un
a HI-PR, dejando LO-PR abierto a la atmósfera. manómetro de exactitud reconocida, y otra desde una
• Vacío: igual gue para Presión, pero invirtiendo las fuente disponible de presión.
conexiones a proceso. Deje el conector no utilizado 2. Aplique presión lentamente, teniendo en cuenta gue el
abierto a la atmósfera. presóstato y el manómetro pueden tener diferentes tiem-
pos de reacción debido a diferencias en volumen de aire,
4. Las conexiones electricas se efectúan mediante ter- además de otras característcas mecanicas diferentes. La
minales a tornillo, marcados “ Common” (Común); “Norm aproximación final al punto de trabajo debe ser muy
Open” (Normal Abierto) y “Norm Closed: ( Normal lenta.
Cerrado). Los contactos se invierten al incrementarse la 3. Asegúrese que el presóstato está en posición correcta
presión por sobre el ajuste (set point). de funcionamiento, o por lo menos en la posición que
será montado. Recuerde que el funcionamiento correcto
5. La corriente no debe exceder do los 15 A sobre carga de la unidad corresponde a montaje vertical del diafrag-
resistiva, La capaciedad del interruptor decrece con car- ma.
gas inductivas, o ciclos rápidos de conmutación. Cuando
estas condiciones se presenten, o se esté en dudas C. En aplicaciones muy críticas, es conveniente durante
acerca de las mismas, se recomienda limitar la corriente los primeros meses de servicio verificar el punto de tra-
a 10 A para prolgar la vida util de interuptor. Otro méto- bajo, y eventualmente restablecer el contacto varias
do consiste enaumentar la capacidad de corriente del veces, para compensar cambios iniciales en la tension
interruptor mediante un relé para alta corriente o contac- del resorte antagónico, y diafragma. En la mayoría de los
tor. Consulte al Representante de DWYER en caso casos, esto no es necesario.
necesario.
MANTENIMIENTO
Las partes móviles y contactos están sellados, siendo
inalterables. El único ajuste disponible es del punto de
trabajo. Evite ingreso de suciedad y acumulación
humedad. No se requiere lubricación periódica.

©Copyright 2010 Dwyer Instruments, Inc. Printed in U.S.A. 2/10 FR# 26-440232-00 Rev. 2

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