Dwyer Instruments 1950G-10-B-24-NA User manual

Series 1950G – Integral Explosion-Proof Pressure Switches

®

Specications - Installation and Operating Instructions

Bulletin E-57G

Set point

adjustment screw

1/2˝ female NPT

electrical conduit

connection

Vent drain

plug

The Series 1950G Explosion-Proof Switch combines the best features of the
popular Series 1900 Pressure Switch with a compact explosion-proof housing.

This unit is UL, CSA, FM listed for use in Class I, Groups A*, B, C, D, Class II, Groups
E, F, & G and Class III atmospheres and Directive 2014/34/EU (ATEX) Compliant for

2813 II 2G Ex db IIB+H2 T6 Gb. IECEx certied Ex db IIB+H2 T6 Gb (-40°C
< Ta < + 60°C) units are available. It is also totally rain-tight for outdoor installations.
Six models allow set-points from 0.07 to 20 in w.c. (1.78 mm to 508.0 mm w.c .).

Easy access to the SPDT relay for electrical hook-up is provided by removing the top
plate of the aluminum housing. A captive screw allows the cover to swing aside while
remaining attached to the unit. Adjustment to the set point of the switch can be made
without disassembly of the housing. The unit is very compact, about half the weight
and bulk of equivalent conventional explosion-proof switches.

Attention: Units with the “NA” sufx are not Directive 2014/34/EU (ATEX) compliant.

These units are not intended for use in potentially explosive atmospheres in the EU.
These units may be CE marked for other Directives of the EU.

External

ground screw

Captive
screw

UL, CSA, FM Listed For

CL, I GR. A*, B, C, D - CL. II GR. E, F, G - CL. III

ATEX Compliant for

2813 II 2G Ex db IIB+H2 T6 Gb

EU-Type Certicate Number: DEMKO 19 ATEX 2216X
ATEX Standards:
EN 60079-0, EN 60079-1

IECEx Certied for:

Ex db IIB+H

IECEx Certicate of Conformity:

IECEx UL 19.0045X
IECEx Standards:
IEC 60079-0, IEC 60079-1
UKCA Ex Compliant for
Ex db IIB+H2 T6 Gb

UKCA Ex Certicate

UL 21UKEX2362X
UKCA Ex Standards
EN 60079-0, EN 60079-1

SPECIFICATIONS

Service: Air and compatible combustible gases.

Wetted Materials: Contact factory.

Temperature Limits: 0 to 140°F (-17 to 60°C). Note: Set point drift may occur with
ambient temperature changes.

Pressure Limits: 45 in w.c. (11.2 kPa) continuous; 10 psig (68.95 kPa) surge.
Enclosure Rating: IP54, NEMA 3, 7 and 9.
Switch Type: 1 Form C relay (SPDT).
Electrical Rating: 10A, 120/240 VAC, 28 VDC. Resistive 50 mA, 125 VDC.
Power Requirements: 24 VDC ±10%. 120 or 240 VAC ±10% optional.
Electrical Connections: Internal terminal block.
Process Connections: 1/8˝ female NPT.

Mounting Orientation: Diaphragm in vertical position. Consult factory for other
position orientations.
Set Point Adjustment: Screw type on top of housing.

Weight: 2 lb 15.7 oz (1.35 kg).

Note: References to ATEX apply to UKCA Ex.

MODEL 1950G SWITCHES:
OPERATING RANGES AND DEADBANDS

To order Specify
Model Number*

1950G-00-B-__
1950G-0-B-__
1950G-1-B-__
1950G-5-B-__
1950G-10-B-__
1950G-20-B-__

*Specify either 24 for 24 VDC, 120 for 120 VAC or 240
for 240 VAC when ordering. Example: 1950G-00-B-120

*Add “NA” sufx for models with UL, CSA and FM

approvals only. Example: 1950G-00-B-120-NA

2 T6 Gb (-40°C < Ta < +60°C)

Approximate Dead

Operating

Range
in w. c.

0.07 to 0.15

0.15 to 0.5

0.4 to 1.6

1.4 to 5.5

3.0 to 11.0

4.0 to 20.0

Band
At Min.

Set Point

0.04

0.06

0.11

0.4

0.9

1.2

At Max.

Set Point

0.06

0.11

0.29

0.9

1.8

3.0

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[42.86]

RANGE

17/64˝ DIA. MTG. HOLES [2]

[10.312]

LOCKWASHER

CONDUCTOR

FRONT VIEW DETAIL

SIDE VIEW DETAIL

ADJUSTMENT

SCREW

1/2˝ NPT

ELECTRICAL

CONDUIT

CONNECTION

1/8˝ NPT HIGH

PRESSURE PORT

1-11/16

EXTERNAL GROUND

4-7/8

[123.8]

5-7/16
[138.1]

1/8˝ NPT

LOW PRESSURE

PORT

VENT

DRAIN

PLUG

3-1/2

[88.90]

1-17/32

[38.89]

CAPTIVE

SCREW

13/32

Figure A

1950G switch outline dimensions

INSTALLATION

1. Select a location free from excess vibration and corrosive atmospheres where
temperatures will be within the limits noted under Physical Data on page 1. Switch
may be installed outdoors or in areas where the hazard of explosion exists. See

page 1 for specic types of hazardous service.

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.

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 ow
can be used. Connect to the two 1/8˝ female NPT pressure ports as noted below.

A. Differential pressures - connect pipes or tubes from source of greater pressure
to high pressure port marked HIGH PRESS, and from source of lower
pressure to low pressure port marked LOW PRESS.

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

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

4. To make electrical connections, remove the three hex head screws from the
cover and after loosening the fourth captive screw, swing the cover aside. Electrical
connections to the standard single pole, double throw relay and AC supply voltage
connections to the unit, are provided by means of terminals marked “COM”, “NO”,
“NC”, “~” and “~” (See Figure A). Electrical connections to the standard single pole,
double throw relay and DC supply voltage connections to the unit, are provided by
means of terminals marked “COM”, “NO”, “NC”, “+” and “-” (See Figure B.). The
normally open contacts close and the normally closed contacts open when
pressure increases beyond the setpoint. Switch loads for standard models should

not exceed the maximum specied current ratings as stated on page 1. For ATEX,

IECEx compliance, cables and cable glands suitable for temperature of at least

105°C shall be used. The cable entry device shall be of certied ameproof type,
suitable for the conditions of use and be correctly installed. Refer to Certicate

No.: IECEx UL 19.0045X for conditions of safe use for IECEx Compliant units.
Switch capabilities decrease with an increase in ambient temperature, load
inductance, or cycling rate.

Figure B

For units supplied with both internal and external bonding terminals, the ground screw
inside the housing must be used to ground the control. The internal bonding screw is
for supplementary bonding when allowed or required by local code. When external
bonding conductor is required, conductor must be wrapped a minimum of 180° about
the external bonding screw. See below.

SCREW

CLAMP PLATE

CLAMP

ADJUSTMENT

To change setpoint:
A. Remove the plastic cap and turn the slotted Adjustment Screw at the top of the
housing clockwise to raise the setpoint pressure and counter-clockwise to lower
the setpoint. After calibration, replace the plastic cap and re-check the setpoint.

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 ow restriction. Run one lead to the pressure

switch, another to a manometer of known accuracy and appropriate range, and

apply pressure through the third tube. Make nal approach to the setpoint very

slowly. Note that manometer and pressure switch will have different response

times due to different internal volumes, lengths of tubing, uid 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 Dwyer nameplate in an
upright position.

C. For highly critical applications check the setpoint adjustment and if necessary,
reset it as noted in step A.

MAINTENANCE

The moving parts of these switches need no maintenance or lubrication. The only
adjustment is that of the setpoint. Care should be taken to keep the switch reasonably
clean. Periodically the vent drain plug should be rotated then returned to its original
position. This will dislodge deposits which could accumulate in applications where

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there is excessive condensation within the switch. Repairs to be conducted by Dwyer
Instruments, LLC. Cover bolts are Class 10.9 35 mm long.