Bacharach MGS-250 User manual

1: OPERATING AREA AND CONDITIONS
The Bacharach MGS-250 is an instrument for the
connuous monitoring of refrigerant gases.
The instrument is powered by 24V AC or DC. The
output signal can be selected as either voltage or
current. The on-board relay can be used to switch
alarm devices.
2: SAFETY INSTRUCTIONS
USER MANUAL: Before using this equipment,
carefully read and strictly follow the User Manual
(part number 6490-9000). The user must fully
understand and strictly observe the instrucons.
Use the equipment only for the purposes listed and
under the condions specified in those documents.
CODE COMPLIANCE: Comply with all local and
naonal laws, rules and regulaons associated with
this equipment.
GENUINE PARTS: Use only genuine Bacharach spare
parts and accessories, otherwise proper funconing
of the equipment may be impaired.
TECHNICIAN USE ONLY: This unit must be installed
by a suitably qualified technician who will install this
unit in accordance with these instrucons and the
standards in their parcular industry/country. Opera-
tors of the unit should be aware of the regulaons
and standards in their industry/country for the
operaon of this unit. These notes are only intended
as a guide and the manufacturer bears no responsi-
bility for the installaon or operaon of this unit.
Failure to install and operate the unit in accordance
with these instrucons and with industry guidelines
may cause serious injury including death and the
manufacturer will not be held responsible in this
regard.
SAFE MOUNTING: This monitor must be connected
by a marked, suitably located and easily reached
switch or circuit-breaker as means of disconnecon.
WARNING: Strictly follow the
instrucons in the Gas Detector
Manual (part number 6490-9000)
available at www.MyBacharach.com.
CAUTION: DO NOT MOUNT the
MGS-250 in an area that may
contain flammable liquids or
vapors. Operaon of electrical
equipment in such an area cons-
tutes a safety hazard.
GAS DETECTOR
INSTALLATION GUIDE
3: SPECIFICATIONS
To open the housing as received use a flat blade
screwdriver and depress the top latch. While push-
ing the latch, grasp the back edge of the housing
near the latch and pull the back away.
4: MOUNTING
Sensor
Housing
6.3 oz
4.0” x 5.5” x 1.5”
180 g
102 x 140 x 37 mm
Weight
and
Dimensions
Temperature
Rating -22° to 104° F -30° to 40° C
Enclosure ABS plastic; UL ammability
rating of 94V-0
Approvals CE, UL/CSA/IEC/EN 61010-1
NOTE: When installed in areas that may be
subjected to water spray, the oponal splash
guard (P/N: 6900-0001) should be used in
conjuncon with the MGS-250. Weight and
dimensions (above) do not include oponal
splash guard.
When mounted, the housing is simply opened by
pressing the top latch with a suitable screwdriver or
other flat blade. With the top latch depressed pull
the housing apart by grasping the sides and pulling
straight out. With the housing separated the
mounng base with terminal blocks will be visible.
IMPORTANT: Do not apply caulking or
other material around the gas detector
base. The gas detector relies on air
exchange through the spaces between the
base and the gas detector housing. Do not
obstruct the small gap around the housing
and the base with any material.
ACCESSIBILITY: The mounng locaon of the moni-
tor should allow it to be easily accessible for visual
monitoring and servicing.
VIBRATION FREE LOCATION: Do NOT mount the
MGS-250 directly to vibrang machinery as the
vibraons may degrade the gas detector’s perfor-
mance.
PLACEMENT GUIDELINES: The MGS-250 should be
installed plumb and level and securely fastened to a
rigid mounng surface.
WATER SPRAY: When installed in areas that may be
subjected to water spray, the oponal splash guard
(P/N: 6900-0001) should be used in conjuncon with
the MGS-250.
ENVIRONMENTAL CONSIDERATIONS: Carefully
consider the full range of environmental condions
to which the instruments will be exposed.
TARGET GAS CONSIDERATIONS: The physical data of
the gas or vapor to be detected must be observed.
APPLICATION CONSIDERATIONS: The specifics of
the applicaon (for example, possible leaks, air
movement/dra, etc.) must be observed.
ACCESSIBILITY CONSIDERATIONS: The degree of
accessibility required for maintenance purposes
must be granted.
ACCESSORY CONSIDERATIONS: The types of
oponal and accessory equipment that will be used
with the system must be kept in mind.
ELECTRONIC CONSIDERATIONS: The system contains
sensive electronic components that can be easily
damaged. Do not touch nor disturb any of these
components.
Mount the MGS-250 according to the above consid-
eraons, product dimensions (see Secon 3), maxi-
mum wiring lengths (see Secon 5), and the corre-
sponding mounng dimensions shown in the illustra-
ons that follow.
STEP 1: Open the housing.
STEP 2: Posion the base to the pre-determined
(acceptable) mounng locaon. Use the gas detec-
tor base to mark the mounng locaons as needed.
The hole paern on the back plate is sized to mount
the gas detector onto various electrical juncon
boxes. The other holes may be used as needed to
mount the gas detector to other structures, or onto
a wall.
STEP 3 - FOR WALL MOUNT: Aach the MGS-250
base to the mounng surface using two #6 screws
(provided) through two of the mounng holes, being
careful not to over-ghten the screws.
STEP 3 - FOR JUNCTION BOX MOUNT: Aach the
MGS-250 base to the juncon box (using mounng
hardware provided with your juncon box) through
the two juncon box holes.
STEP 4: Unless you are ready to wire the device,
carefully snap the cover onto the base unit.
P/N: 6490-9004
Revision 0
January 25, 2016
4: MOUNTING (CONTINUED) 4: MOUNTING (CONTINUED)
Flat Surface
Mounng Holes
(6 Places)
NOTE: Use #6
screw or smaller for
wall mounng.
Juncon Box
Mounng
Holes (2 Places)
Cable Gland
(Oponal) or
Blanking Plug
(Not Shown)
Cable Gland
(Installed)
DO NOT apply caulking or sealant on or
around the MGS-250 or its base.

World Headquarters
621 Hunt Valley Circle
New Kensington, PA 15068 USA
Phone: [phone] • Fax: [phone]
Toll Free: 1-800-736-4666
Website: www.MyBacharach.com
E-mail: [email protected]
5: WIRING AND CONFIGURATION
CABLE OPENINGS: Each MGS-250 transmier
contains two cable glands. The le cable gland
comes pre-installed, and the right cable gland is
oponal and must be installed if needed. If the right
cable gland is not needed, the blanking plug (includ-
ed in the mounng kit) must be installed instead.
114A Georges Street Lower
Dun Laoghaire • Co Dublin • Ireland
Phone: [phone] • Fax: [phone]
NOTE: To make wiring connecons,
you must first open the MGS-250
cover panel. The cover panel
detatches by pressing the top latch
with a suitable screwdriver or other
flat blade.
NOTE: Aer wiring is completed,
carefully re-assemble the enclosure.
Aer installaon is complete, be sure to
refer to the User Manual (part number
6490-9000) at
www.MyBacharach.com for addi-
onal instrucon for proper operaon.
Refer to the User Manual (part number 6490-
9000) at www.MyBacharach.com for detailed
instrucons on accessing the internal components
for wiring.
24VAC
L N
24VDC
+ GND
OUT
GND +
RS485
B A SH
RELAY
NC C NO
1 2 3 4 5 6 7 8 9 10 11 12
2
3
4
9
10
10
Terminal Block
Posions 1-6
Terminal Block
Posions 7-12
24 VAC NEUTRAL
1 2 3 4 5 6 7 8 9 10 11 12
24VAC
L N + GND
OUT
GND +
RS485
B A SH
RELAY
NC C NO
24 VDC
24 VDC +
(#3)
24 VDC Ground
(#4)
1 2 3 4 5 6 7 8 9 10 11 12
24VAC
L N + GND
OUT
GND +
RS485
B A SH
RELAY
NC C NO
24 VDC
WARNING: Incorrect wiring may
permanently damage the gas detector,
and void the warranty. Double check
all terminaons before applying power.
WARNING: The MGS-250 must be
powered by either:
• a suitable UL 60950/CSA cerfied
power supply that is isolated from line
voltage by double insulaon, or
• an appropriately rated UL listed/CSA
Class 2 transformer.
Failure to comply can result in personal
injury or death.
WARNING: Neutral
polarity must be
maintained across
units.
TRANSFORMER
24 VAC
NEUTRAL
120 VAC
SUPPLY
24
VAC
NEUTRAL 24
VAC
NEUTRAL 24
VAC
NEUTRAL
Analog Output
Ground (#5) Analog Output Signal (+) (#6)
1 2 3 4 5 6 7 8 9 10 11 12
24VAC
L N + GND
OUT
GND +
RS485
B A SH
RELAY
NC C NO
24VDC
Use 18 to
20 AWG wire
NC (#10) NO (#12)
COM (#11)
1 2 3 4 5 6 7 8 9 10 11 12
24VAC
L N + GND
OUT
GND +
RS485
B A SH
RELAY
NC C NO
24VDC
POWER (AC)
POWER (DC) ANALOG OUTPUT
ALARM OUTPUT
RS-485 “B”
Inverted (#7)
RS-485 “A”
Non-inverted (#8)
Shield (#9)
1 2 3 4 5 6 7 8 9 10 11 12
24VAC
L N + GND
OUT
GND +
RS485
B A SH
RELAY
NC C NO
24VDC
MODBUS NETWORK
IMPORTANT: For Modbus network
communicaons wiring, use only 18-24
AWG shielded twisted pair wire with
120 ohm characterisc impedance.
Refrigeraon or
Building
Controller
Terminator: IN
RS-485 TERMINATOR
OUT
IN
OUT
IN
OUT
IN
OUT
IN
OUT
IN
OUT OUT OUT IN
IMPORTANT: Be sure to enable the
terminaon resistor on the device at
each end of the network.