Dungs GAO-A2 Series User manual

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Gxx_A2 Sales Brochure • P/N 226 359 • Edi 01/08
Gas Pressure Switch
for DMV safety shutoff valves
GAO-A2…
GMH-A2…
GML-A2…
Description
The GAO-, GMH-, and GML-A2… pres-
sure switches are compact, ventless gas
pressure switches for modular valve train
components.
A2 pressure switches are suitable for
making and/or breaking a circuit when
the medium pressure changes relative
to the set point. The set point can be
set in the eld by an adjustable dial with
an integrated scale . The switches incor-
porate a vent limiter as per UL 353 and
limits the escape of gas less than 1.0 CFH
of natural gas at 7 PSI if internal switch
diaphragm ruptures.
Application
The GAO-, GMH-, and GML-A2… pres-
sure switches are recommended for
industrial and commercial heating ap-
plications with DMV dual modular valves,
SV safety valves, MBC multifunctional
controls, and FRI modular pressure regu-
lators. Various mounting options allow
direct mounting on the housing.
The GAO-, GMH-, and GML-A2… pres-
sure switch is suitable for natural gas,
propane, butane, air and other inert
gases. Suitable for up to 0.1% by vol-
ume, dry H2S.
UL Listed
• UL 353
• File # MH 16628
CSA Certified
• CSA C22.2 No. LR 53222
• File # 201527
FM Approved
• Class 3510, 3530
• File # J.I. 1Y9A9.AF
Commonwealth of Massachusetts
Approved Product
• Approval code G3-0106-191
• Gas pressure switch
Codes and Standards
This product is intended for installations
covered by but not limited to NFPA
85, NFPA 86, UL 795, CSD-1, ANSI
Z83.4, ANSI Z83.18, ANSI Z21.13,
and CSA B149.3.
DUNGS is an ISO 9001
manufacturing facility.

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GAO-A2… SPDT pressure switch requires no auxiliary power to actuate. The GAO-A2… is suitable for making and/or
breaking a circuit when the set point is exceeded or undershot. A tripped switch is indicated by a neon light after set point
is exceeded or undershot. Automatic reset when pressure returns below or above set point.
GMH-A2… SPDT pressure switch requires no auxiliary power to actuate. The GMH-A2… is suitable for making and/or
breaking a circuit when the set point is exceeded. A tripped switch is indicated by a neon light after set point is exceeded.
Manual reset is required to reset the switch.
GML-A2… SPDT pressure switch requires no auxiliary power to actuate. The GML-A2… is suitable for making and/or break-
ing a circuit when the set point is undershot. A tripped switch is indicated by a neon light after set point is undershot.
Manual reset is required to reset the switch.
GMH (Operating state shown)
As pressure rises, 2 NO closes, 1
NC opens, and Neon light ON (fault),
switch trips and locks out.
Specifications
Max. operating pressure
Pressure connection
Temperature range:
For series ending in -2,-3,-5, and -6
For series ending in -8
Materials
Electrical ratings
Nominal current
Electrical connection
Enclosure rating
Setting tolerance
Vent Limiter
GAO-A2-4-2,3,5,6 7 PSI (500mbar)
GMH- and GML-A2-4-4,6 7 PSI (500mbar)
GAO-, GMH- and GML-A2-4-8 14 PSI (1000 mbar)
O ring ange connection on underside of pressure switch
Ambient temperature -40 °F to +140 °F (-40 °C to +60 °C)
Medium temperature -40 °F to +140 °F (-40 °C to +60 °C)
Ambient temperature -22 °F to +140 °F (-30 °C to +60 °C)
Medium temperature -22 °F to +140 °F (-30 °C to +60 °C)
Housing Aluminium
Switch Polycarbonate
Diaphragm NBR-based rubber
Switching contact Silver or Gold
AC eff. min. 24 V max. 240 V
DC min. 24 V max. 48 V
Silver (Ag) contact ratings Gold (Au) contact ratings
AC 10A resistive @ 120 VAC
AC 8A inductive @ 120 VAC
DC min. 20mA @ 24 VDC DC max. 5mA @ 5 VDC
DC max. 2A @ 24 VDC DC max. 20mA @ 24 VDC
Screw terminals via 1/2” NPT conduit connection
NEMA Type 4
±15% switching point deviation referred to set point. Adjusted as pressure rises or
as pressure falls, vertical diaphragm position.
Incorporates a vent limiter as per UL 353 and limits the escape of gas less than 1.0
CFH of natural gas at 7 PSI if internal switch diaphragm ruptures.
GML (Operating state shown)
As pressure falls, 2 NO opens, 1
NC closes, Neon light ON (fault), switch
trips and locks out.
GAO (Shown as a high gas limit)
As pressure rises above set point,
1 NC opens, 2 NO closes, Neon light
ON (fault). As pressure falls below
setpoint, switch resets: 1 NC closes
and 2 NO opens.

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Adapters / replacement parts /
Accessories
A2 Mounting kit (included with switch)
DMV & MBC Port 3 adapter (side mount
for high pressure switch)
Replacement conduit adapter
Replacement conduit adapter
Replacement cover
Replacement cover
Screw for replacement cover
Replacement light
Replacement light
Replacement light
Male plug for A2
(use with 210-318 female connector)
Male plug for A2
(use with 210-318 female connector)
DIN Connector (female plug) for A2
(For use with 219-659 or 227-644)
Order No.
226-188
214-975
240-671
220-566
228-732
233-113
237-675
244-156
248-240
244-157
219-659
227-644
210-318
For equipment
GAO, GMH, GML
DMV-D(LE) 701 - 703
MBC series 1000-4000
GAO, GMH, GML
GAO, GMH, GML
GAO
GMH, GML
GAO, GMH, GML
GAO, GMH, GML
GAO, GMH, GML
Gold contact versions
GAO
GMH, GML
GAO, GMH, GML
Notes
M4 Screws, 10.5 x 2.25 O-ring
NPT 1/2“ - NPT 2“
Pg 11 to 1/2“ NPT adapter
M20 to 1/2“ NPT adapter
120 VAC, yellow bulb
120 VAC, green bulb
24 VDC/VAC, yellow bulb
Dimensions inch (mm)
GAO-, GMH-, GML-A2…
Slot for O-ring
Definition of switching hysteresis ∆p
The pressure difference between the upper
and lower switching pressures

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A2 mounting options
FRI gas pressure regulator
Pressure
tap
1
2
3
M
ounting
possible?
yes
yes
yes
A2 mounting options
DMV 701-703 Dual modular valve
Pressure
tap
1
2
3
4
5
Mounting
possible ?
yes
yes
yes, with # 214-975
yes, horizontal
yes, vertical with #225-047
yes, horizontal
yes, vertical with #225-047
A2 mounting options
DMV 525,5040-5125/11Dual
modular valve
Pressure
tap
1
2
3
4
5
6
M
ounting
possible?
yes
yes
yes
yes
no
no

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MBC ports
20
16 12 8
4
pBr
2
3
11
44
5
5
3
3
2
2
1
1
5
4
20
16 12 8
4
pBr
A2 mounting options
MBC series multifunctional
control
Pressure
tap
1
2
3
4
5
Mounting
possible ?
yes
yes
yes, with # 214-975
yes, horizontal
yes, vertical with #225-047
yes, horizontal
yes, vertical with #225-047
SV 1005 and SV 1007 Series ports
(pressure switch only mounts to upstream port #2)
A2 mounting options
SV 1005 and SV 1007 series safety
valve
Pressure
tap
1
2
3
4
Mounting
possible ?
no
yes
no
no
A2 mounting options
SV 1010, SV 1012, SV 1015, and
SV 1020 series safety valve
Pressure
tap
1
2
3
4
5
Mounting
possible ?
yes
yes
yes
no
yes

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We reserve the right to make any changes in the interest of technical progress.
Gas Pressure Switch
for DMV safety shutoff valves
GAO-A2…
GMH-A2…
GML-A2…
Type
GAO-A2…
pressure switch
GMH-A2…
pressure switch
GML-A2…
pressure switch
Version
GAO-A2-4-2
GAO-A2-4-3
GAO-A2-4-5
GAO-A2-4-6
GAO-A2-4-8
GMH-A2-4-4
GMH-A2-4-6
GMH-A2-4-8
GML-A2-4-4
GML-A2-4-6
GML-A2-4-8
Order No.
217-085A
217-086A
217-087A
217-088A
217-089A
217-323A
217-324A
217-325A
217-337A
217-338A
217-339A
Setting
range
in. W.C.
0.16 - 1.20
0.40 - 4.00
2.00 - 20.00
12.0 - 60.0
40.00- 200.0
1.00 - 20.00
12.0 - 60.0
40.0- 200.0
1.00 - 20.00
12.0 - 60.0
40.0 - 200.0
Switching hysteresis
in. W.C.
≤ 0.12
≤ 0.20
≤ 0.40
≤ 1.2
≤ 4.0
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Karl Dungs GmbH & Co. KG
P.O. Box 12 29
D-73602 Schorndorf, Germany
Phone [phone]
Fax [phone]
e-mail [email protected]
Internet http://www.dungs.com
Karl Dungs Inc.
524 Apollo Drive, Suite 10
Lino Lakes, MN 55014, U.S.A.
Phone [phone]
Fax [phone]
e-mail [email protected]
Internet http://www.dungs.com/usa/
All switches have 120 VAC neon lights factory installed
Factory
Calibration

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Karl Dungs, Inc
524 Apollo Drive,Suite 10 Lino Lakes, MN 55014 U.S.A.
Phone: [phone] Fax: [phone] E-mail: [email protected]
Enclosure Rating
NEMA Type 4
Maximum Operating Pressure
7 PSI (500 mbar)
Ambient / Fluid Temperature
Versions -2, -3, -5, & -6; -40°F to +140°F; (-40°C to +60°C)
Version -8; -20°F to +140°F; (-30°C to +60°C)
Materials in contact with Gas
Housing: aluminum & steel; Diaphragm: NBR-based rubber
Approvals
UL Listed: File #. MH 16628
CSA Certified: File # 201527
FM Approved: Report J.I. 1Y9A9.AF
Commonwealth of Massachusetts Approved Product
Approval code G3-0106-191
GAO-A2, GMH-A2, and GML-A2
Gas Pressure Switch
Installation Instructions
SPECIFICATIONS
High/low ventless gas pressure switch (SPDT) with automatic or manual reset. Includes visual indication of switch position.
Mounts directly to various ports on the SV, DMV and MB series valves and FRI series regulators.
Gxx_A2 Installation Manual - P/N 80111 - Ed. 01/09
Gases
Natural gas, propane, butane, air and other noncorrosive
gases. Suitable for up to 0.1% by volume, dry H2S.
Switch action
GAO: high/low limit, NC breaks on rise, automatic reset
GMH: high limit, NC breaks on rise, manual reset
GML: low limit, NO breaks on fall, manual reset
Switch Type and Contact Rating
SPDT; 10 A res., 8 FLA, 48 LRA @120 Vac
Vent Limiter
Incorporates a vent limiter as per UL 353 and limits the
escape of gas less than 1.0 CFH of natural gas at 7 PSI if
internal switch diaphragm rupture.
Electrical Connection
1/2” NPT conduit connection via screw terminals
ATTENTION
• Read these instructions carefully.
• Failure to follow them and/or improper installation may
cause explosion, property damage and injuries.
• Installation must be done with the supervision of a
licensed burner technician.
• Check the ratings in the specications to make sure that
they are suitable for your application.
• Never perform work if gas pressure or power is applied,
or in the presence of an open flame.
• Ensure that the switch is not subjected to vibration during
operation.
• Once installed, perform a complete checkout including
leak testing.
• Label all wires prior to disconnection when servicing.
Wiring errors can cause improper and dangerous
operation
• Verify proper operation after servicing.
• The system must be installed, used, and maintaned to
meet all applicable national and local code requirements
such as but not limited to NFPA 85, NFPA 86, UL 795,
CSD-1, ANSI Z83.4, ANSI Z83.18, ANSI Z21.13, and
CSA B149.3.

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MOUNTING
• Remove the clear cover from the switch.
• Use 14 or 16 AWG wire rated for at least 75°C
• Route the wires through the conduit connector
• Connect the wiring to the appropriate screw terminals.
CAUTION: All wiring must comply with local elec-
trical codes, ordinances and regulations.
WIRING
CAUTION: Do not exceed the switch ratings given
in the specifications and on the switch.
Recommended Mounting Procedure
• Remove the clear cover of the switch in order to remove
the thread forming socket head screws.
• Verify that the O-ring and the groove, in which the O-oring
is placed, are clean and free of notches or burrs.
• Place the O-ring into the groove on the back of the
pressure switch. This is located on the flate side of the
aluminum housing.
• Using a 3 mm hex wrench, remove the G 1/8 plug from
the port on which the switch is to be mounted. This will
be either a flange, the side of the FRI regulator, or a G 1/8
port of Dungs safety shutoff valve.
• Mount the switch onto the port using the thread-forming
socket head screws.
• The O-ring can slide during the mounting process, so it is
recommended that as the switch is pressed onto the port,
visually verify that the O-ring remains in the groove.
• Tighten the screws but do not exceed 22 lb-in.
• Perform a leak test to verify that no leakage occurs around
the O-ring.
GAO (Operating state shown as a
high limit). As pressure rises above
set point, 1 NC opens, 2 NO closes,
Neon light ON (fault). As pressure
falls below set point, switch resets: 1
NC closes and 2 NO opens.
GMH (Operating state shown)
As pressure rises above set-
point, 2 NO closes, 1 NC opens,
and Neon light ON (fault), switch
trips and locks out.
GML (Operating state
shown)
As pressure falls above set-
point, 2 NO opens, 1 NC closes,
Neon light ON (fault), switch trips
and locks out.
Wiring terminal
illustration

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Annually check the switch for proper operation
Set Point Calibration
The set point dial of the GAO and GMH is factory calibrated
with increasing pressure (GML: decreasing pressure). Due
to hysteresis, the GAO switch will actuate at a slightly lower
point as the pressure decreases.
Adjusting the Set Point
• Remove the clear cover from the switch.
• Turn the dial until the desired trip pressure is opposite the
white arrow (mark) on the yellow dial face.
• After adjusting the set point for normal operation check to
see that the gas pressure switch operates as intended.
• Use an accurate pressure gauge connected upstream
from the switch to measure the actual pressure.
• Replace the clear cover.
OPERATION AND ADJUSTMENT
Automatic Reset
The NC contact of the GAO breaks when pressure rises
above the set point. It makes automatically when pressure
returns to the normal operating level.
Manual Reset
The NC contact of the GMH breaks when pressure rises
above the set point. The NO contact of the GML breaks
when pressure falls below the set point. Neither of the
switches will return to their former position automatically. To
reset, wait until the pressure returns to the normal operat-
ing level. Then press and release the clear cover over the
red reset button in the center of the yellow dial face; it is not
necessary to remove the cover. The neon light indicates a
fault condition for the GML and GMH series and for the GAO
series when used as a high gas limit. The lead for the light
wired to terminal #2 on the GAO series should be wired to
terminal #1 when used as a low gas limit.

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MAINTENANCE AND TESTING
Annually check the switch for proper operation
Low Gas Pressure Switch:
First, connect a meter capable of reading +/- 0 ohms to•
the NO and COM contacts, and verify that the NO and
COM contacts are made. Measure the resistance, and if
the resistance is more than 1 ohm, remove switch from
service. is more than 1 ohm. (See terminal illustration
below for guidance).
Then, verify that the low gas pressure switch will change•
state when a low gas condition is sensed by connect-
ing a meter capable or reading +/- 0 ohms to the NC
and COM contacts and then by causing the switch to
go into a fault condition. Once the fault occurs, Measure
the resistance, and if the resistance is more than 1 ohm,
remove switch from service. is more than 1 ohm.
To cause the fault, perform one of the two procedures:•
Turn the pressure switch setpoint counterclockwise1.
until the switch trips.
Depressurize the volume of gas the low gas pressure2.
switch is sensing. For FRI/6 regulators, this can be
done by opening the side tap on the oppositive side
of the FRI/6 regulator. For DMV and MBC safety
shutoff valves, this can be done opening the port
1 pressure tap. For SV valves, open port 1 of the
upstream valve.
Allow the burner to go through a startup sequence, and•
then verify that the burner faults and is not allowed to
light off.
Close all test taps (ports) and open upstream ball valve.•
When finished, close all pressure test points used, and•
then open the upstream ball valve SLOWLY to allow gas
pressure to gradually bleed into the system.
CAUTION: Opening the upstream ball valve too fast
can permanently damage the regulator.
High Gas Pressure Switch:
First, connect a meter capable of reading +/- 0 ohms to•
the NC and COM contacts, and verify that the NC and
Measure the resistance, and if the resistance is more
than 1 ohm, remove switch from service. is more than 1
ohm.
Then, verify that the high gas pressure switch will•
change state when a high gas condition is sensed by
connecting a meter capable or reading +/- 0 ohms to
the NO and COM contacts and then by causing the
switch to go into a fault condition.
To cause the fault, perform one of the two procedures:•
Turn the pressure switch setpoint clockwise until the1.
switch trips.
Pressurize the volume of gas the high gas pressure2.
switch is sensing. This can be done by closing the
downstream ball valve, opening port 3 tap on a DMV
and MBC safety shutoff valves, or port 2 or 3 of the
downstream SV valve, and then using a pump to
pressurize the test chamber.
Measure the resistance across the NO and COM•
contacts. If the resistance is more than 1 ohm, remove
switch from service.
Allow the burner to go through a startup sequence, and•
then verify that the burner faults and is not allowed to
light off.
When finished, close all test taps (ports) and open the•
dowmstream ball valve.
NOTE: A resistance of more than 1 ohm indicates
that the switch contacts are starting to either cor-
rode or carbonize.
Terminal Illustration
Do not similate fault conditions while the
burner is firing.