Bacharach MGS-350 User manual

MGS-350
Gas Detector
Installation and Operation Manual
Instruction 6509-9000
Revision 1 – February 2013
Product Leadership •Training •Service •Reliability

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WARRANTY POLICY
BACHARACH, INC. WARRANTS THIS INSTRUMENT, EXCLUDING SENSORS, TO BE
FREE FROM DEFECTS IN MATERIALS AND WORKMANSHIP FOR A PERIOD OF TWO
YEARS FROM THE DATE OF PURCHASE BY THE ORIGINAL OWNER. THE SENSORS
HAVE A WARRANTY PERIOD OF ONE YEAR FROM THE DATE OF PURCHASE. IF
THE PRODUCT SHOULD BECOME DEFECTIVE WITHIN THIS WARRANTY PERIOD,
WE WILL REPAIR OR REPLACE IT AT OUR DISCRETION.
THE WARRANTY STATUS MAY BE AFFECTED IF THE INSTRUMENT HAS NOT BEEN
USED AND MAINTAINED PER THE INSTRUCTIONS IN THIS MANUAL OR HAS BEEN
ABUSED, DAMAGED, OR MODIFIED IN ANY WAY. THIS INSTRUMENT IS ONLY TO BE
USED FOR PURPOSES STATED HEREIN. THE MANUFACTURER IS NOT LIABLE FOR
AUXILIARY INTERFACED EQUIPMENT OR CONSEQUENTIAL DAMAGE.
DUE TO ONGOING RESEARCH, DEVELOPMENT, AND PRODUCT TESTING, THE
MANUFACTURER RESERVES THE RIGHT TO CHANGE SPECIFICATIONS WITHOUT
NOTICE. THE INFORMATION CONTAINED HEREIN IS BASED ON DATA CONSIDERED
ACCURATE. HOWEVER, NO WARRANTY IS EXPRESSED OR IMPLIED REGARDING
THE ACCURACY OF THIS DATA.
ALL GOODS MUST BE SHIPPED TO THE MANUFACTURER BY PREPAID FREIGHT.
ALL RETURNED GOODS MUST BE PRE-AUTHORIZED BY OBTAINING A RETURN
MERCHANDISE AUTHORIZATION (RMA) NUMBER. CONTACT THE MANUFACTURER
FOR A NUMBER AND PROCEDURES REQUIRED FOR PRODUCT TRANSPORT.
SERVICE POLICY
BACHARACH, INC. MAINTAINS AN INSTRUMENT SERVICE FACILITY AT THE
FACTORY. SOME BACHARACH DISTRIBUTORS / AGENTS MAY ALSO HAVE
REPAIR FACILITIES, HOWEVER, BACHARACH ASSUMES NO LIABILITY FOR
SERVICE PERFORMED BY ANYONE OTHER THAN BACHARACH PERSONNEL.
REPAIRS ARE WARRANTED FOR 90 DAYS AFTER DATE OF SHIPMENT
(SENSORS, PUMPS, FILTERS AND BATTERIES HAVE INDIVIDUAL
WARRANTIES). SHOULD YOUR INSTRUMENT REQUIRE NON-WARRANTY
REPAIR, YOU MAY CONTACT THE DISTRIBUTOR FROM WHOM IT WAS
PURCHASED OR YOU MAY CONTACT BACHARACH DIRECTLY.
IF BACHARACH IS TO DO THE REPAIR WORK, SEND THE INSTRUMENT,
PREPAID, TO BACHARACH, INC. AT THE FOLLOWING ADDRESS.
BACHARACH, INC.
621 HUNT VALLEY CIRCLE
NEW KENSINGTON, PA 15068
ATTENTION: SERVICE DEPARTMENT
ALWAYS INCLUDE YOUR RMA #, ADDRESS, TELEPHONE NUMBER, CONTACT
NAME, SHIPPING/BILLING INFORMATION AND A DESCRIPTION OF THE
DEFECT AS YOU PERCEIVE IT. YOU WILL BE CONTACTED WITH A COST
ESTIMATE FOR EXPECTED REPAIRS PRIOR TO THE PERFORMANCE OF ANY
SERVICE WORK. FOR LIABILITY REASONS, BACHARACH HAS A POLICY OF

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PERFORMING ALL NEEDED REPAIRS TO RESTORE THE INSTRUMENT TO
FULL OPERATING CONDITION.
PRIOR TO SHIPPING EQUIPMENT TO BACHARACH, CONTACT OUR OFFICE
FOR AN RMA # (RETURNED MERCHANDISE AUTHORIZATION). ALL RETURNED
GOODS MUST BE ACCOMPANIED WITH AN RMA NUMBER.
PACK THE EQUIPMENT WELL (IN ITS ORIGINAL PACKING IF POSSIBLE), AS
BACHARACH CANNOT BE HELD RESPONSIBLE FOR ANY DAMAGE INCURRED
DURING SHIPPING TO OUR FACILITY.
NOTICES
COPYRIGHTS: THIS MANUAL IS SUBJECT TO COPYRIGHT PROTECTION; ALL
RIGHTS ARE RESERVED UNDER INTERNATIONAL AND DOMESTIC
COPYRIGHT LAWS. THIS MANUAL MAY NOT BE COPIED OR TRANSLATED, IN
WHOLE OR IN PART, IN ANY MANNER OR FORMAT, WITHOUT THE WRITTEN
PERMISSION OF BACHARACH, INC.
ALL SOFTWARE UTILIZED AND/OR DISTRIBUTED BY BACHARACH IS SUBJECT
TO COPYRIGHT PROTECTION. ALL RIGHTS ARE RESERVED. NO PARTY MAY
USE OR COPY SUCH SOFTWARE IN ANY MANNER OR FORMAT, EXCEPT TO
THE EXTENT THAT BACHARACH GRANTS THEM A LICENSE TO DO SO. IF THIS
SOFTWARE IS BEING LOADED ONTO MORE THAN ONE COMPUTER, EXTRA
SOFTWARE LICENSES MUST BE PURCHASED.
TECHNICIAN USE ONLY
THIS UNIT MUST BE INSTALLED BY A SUITABLY QUALIFIED TECHNICIAN WHO
WILL INSTALL THIS UNIT IN ACCORDANCE WITH THESE INSTRUCTIONS AND
THE STANDARDS IN THEIR PARTICULAR INDUSTRY/COUNTRY. OPERATORS
OF THE UNIT SHOULD BE AWARE OF THE REGULATIONS AND STANDARDS IN
THEIR INDUSTRY/COUNTRY FOR THE OPERATION OF THIS UNIT. THESE
NOTES ARE ONLY INTENDED AS A GUIDE AND THE MANUFACTURER BEARS
NO RESPONSIBILITY FOR THE INSTALLATION OR OPERATION OF THIS UNIT.
FAILURE TO INSTALL AND OPERATE THE UNIT IN ACCORDANCE WITH THESE
INSTRUCTIONS AND WITH INDUSTRY GUIDELINES MAY CAUSE SERIOUS
INJURY INCLUDING DEATH AND THE MANUFACTURER WILL NOT BE HELD
RESPONSIBLE IN THIS REGARD.

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Table of Contents
SECTION 1. OVERVIEW ................................................................................5
1.1. General Information..................................................................................... 5
1.2. Specifications ............................................................................................... 6
SECTION 2. INSTALLATION AND WIRING ................................................... 14
2.1. General Placement Guidelines................................................................... 15
2.2. Machinery Rooms ...................................................................................... 15
2.3. Refrigerated Spaces ................................................................................... 17
2.4. Chillers........................................................................................................ 17
2.5. Air Conditioning (Direct Systems VRF/VRV) ............................................... 18
2.6. Remote Sensor Head Installation............................................................... 18
2.7. Components Overview and Configuration................................................. 19
2.8. Connecting to an MGS Controller .............................................................. 22
2.9. Connecting to a Repeater .......................................................................... 23
SECTION 3. OPERATION AND STABILIZATION............................................24
SECTION 4. FUNCTIONAL TESTS AND CALIBRATION ..................................25
4.1. Introduction ............................................................................................... 25
4.2. Bump Testing ............................................................................................. 27
4.3. Calibration: Exchange Method................................................................... 30
4.4. Calibration: Gas Method ............................................................................ 32
4.5. Calibration: Gas Method for SC Sensors .................................................... 34
4.6. Calibration: Gas Method for CAT Sensors.................................................. 35
4.7. Calibration: Gas Method for EC Sensors .................................................... 37
4.8. Calibration: Gas Method for IR Sensors ..................................................... 38
SECTION 5.TROUBLESHOOTING ............................................................... 40
DECLARATION OF CONFORMITY....................................................................41

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Section 1. Overview
1.1. General Information
The MGS-350 is a state-of-the-art fixed gas detector which can detect a
wide range of different gases. The gas sensors can be used on a stand-
alone basis or integrated into Controls or Building Management Systems
(BMS).
Supported gas types include the following.
Category Gases
Refrigerant gases
All refrigerant gases including: Ammonia, Carbon
Dioxide, Halocarbons - HFCs, HCFCs, CFCs
Combustible
gases Methane, LPG, Propane, Butane, and Hydrogen
Toxic gases Hydrogen Sulfide in sewage treatment, Carbon
Monoxide in parking garages, etc.
Volatile Organic
Compounds
Acetone, Benzene, Carbon Tetrachloride, Chloroform,
Ethanol, Toluene, Trichloroethylene, etc.
CAUTION: Suitably qualified operators of the unit should be
aware of the regulations and standards applicable to their
industry/country for the operation of this unit. This manual is
only intended as a guide and Bacharach
bears no
responsibility for the installation or operation of this unit.
CAUTION:
Failure to install and operate the unit in
accordance with these instructions and with industry
guidelines may cause serious injury or death.

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1.2. Specifications
Housings Dimensions Weight
Standard
145 x 185 x 80 mm
5.7 x 7.3 x 3.1 in 850 g 1.9 lb
IP66 w/ Digital
Display
175 x 165 x 82 mm
6.9 x 6.5 x 3.2 in 719 g 1.6 lb
IP66
175 x 165 x 82 mm
6.9 x 6.5 x 3.2 in 660 g 1.5 lb
IP66 w/ Splash
Guard
175 x 225 x 82 mm
6.9 x 8.9 x 3.2 in 756 g 1.7 lb
Splash Guard
w/ M42 Thread
75mm x 50 mm
3.0 x 2.0 in 72 g 0.2 lb
IP66 w/ Remote
Sensor Head
175 x 155 x 82 mm
6.9 x 6.1 x 3.2 in 917 g 2.0 lb
Exd
130 x 175 x 90 mm
5.1 x 6.9 x 3.5 in 4003 g 8.8 lb
Exd + Digital
Display
140 x 180 x 130 mm
5.5 x 7.1 x 5.1 in 2322 g 5.1 lb
IP66 w/ Exd
Remote Sensor
Head
175 x 155 x 82 mm
6.9 x 6.1 x 3.2 in 1240 g 2.7 lb
IP66 w/ PRV
Remote Sensor
Head
175 x 155 x 82 mm
6.9 x 6.1 x 3.2 in 900 g 2.0 lb
IP66
Airflow/Duct
Mount
175 x 125 x 82 mm
6.9 x 4.9 x 3.2 in 643 g 1.4 lb
Remote Face
Plate
86 x 86 mm
3.4 x 3.4 in 86 g 0.2 lb

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Category Specification
Power Supply 12-24 VAC 50/60 Hz, 12-30 VDC, 5 W maximum
Power Monitoring Green LED
Visual Alarm Orange LED for low level; Red LED for high level
Analog Outputs 0-5 V, 0-10 V, 4-20 mA
Digital Interface RS-485 (Modbus)
Digital Outputs 2 relays rated 1 A/125 VAC (resistive load)
Standard
Compliance CE mark
UL/CSA/IEC/EN 61010-1
FCC CFR 47 Part 15, Subpart B
Sensor
Information
Electro-
Chemical
(EC)
Semi-
conductor
(SC) Catalytic (CAT) Infrared (IR)
Sensor Life
(Typical) 3 years 5-8 years 5 years 5 years
EC Sensors Formula Typical Detection Range(s)
Ammonia NH30-100 ppm, 0-1,000 ppm, 0-5,000 ppm
Carbon Monoxide CO 0-100 ppm, 0-500 ppm, 0-1,000 ppm
Chlorine Cl20-20 ppm
Chlorine Dioxide ClO20-1 ppm
Ethylene Oxide C2H4O 0-20 ppm
Ethylene C2H40-20 ppm, 0-1,000 ppm
Fluorine F20-1 ppm
Hydrazine N2H40-1 ppm
Silane - Hydride SiH40-5 ppm
Hydrogen H20-1,000 ppm, 0-10,000 ppm, 0-100% LEL
Hydrogen Chloride HCl 0-50 ppm
Hydrogen Cyanide HCN 0-50 ppm
Hydrogen Sulfide H2S 0-30 ppm, 0-200 ppm
Nitric Oxide NO 0-10 ppm, 0-500 ppm
Nitrogen Dioxide NO20-50 ppm

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EC Sensors Formula Typical Detection Range(s)
Oxygen O20-30%
Ozone O30-2 ppm
Phosgene COCl20-1 ppm
Phosphine PH30-5 ppm
Sulfur Dioxide SO20-100 ppm
IR Sensors Formula Typical Detection Range(s)
Carbon Dioxide CO2
Standard
range:
0-10,000, 0-1% volume
Special
request: 0-5,000ppm, 0-2%, 0-5%, 0-10%
Combustible Gases Selected 0-100% LEL, 0-100% volume
CAT Sensors Formula Typical Detection Range(s)
All Combustible
Gasses Selected 0-100% LEL
SC Sensors Example Gases Typical Detection
Range(s)
HFCs R134a, R404A, R407C, R410A, R507 10-10,000 ppm
HCFCs R22 10-10,000 ppm
CFCs R11, R12 10-10,000 ppm
Combustibles Methane (Natural gas), Propane, Butane,
LPG, Isobutane, Ethylene 0-10,000 ppm
Ammonia NH30-10,000 ppm
Hydrogen H20-10,000 ppm
VOCs Acetone, Chloroform, Ethanol, Methanol, Methyl and Methylene Chloride, Ethyl and
Ethylene Chloride 0-10,000 ppm
NOTE: The actual factory calibration gas and detection range
is marked on each instrument.

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Sensor
Types Temperature Ranges
Standard Enclosure IP 66
SC -4º to 122º F (-20º to 50º C) -40º to 122º F (-40º to 50º C)
EC -4º to 104º F (-20º to 40º C) -40º to 104º F (-40º to 40º C)
CAT -4º to 122º F (-20º to 50º C) -40º to 122º F (-40º to 50º C)
IR -4º to 122º F (-20º to 50º C) -40º to 122º F (-40º to 50º C)
For temperature requirements lower than -40
°
, please contact the factory.
Figure 1. MGS-350 Standard Housing

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Figure 2. MGS-350 IP66 Housing (with Splash Guard)

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Figure 3. IP66 Splashguard (M42 x 1.5 Thread)
Figure 4. IP66 Duct Mount Housing

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Figure 5. Exd Housing
Units = mm

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Figure 6. IP66 Housing with Remote Sensor Head
NOTE: For the Exd Remote Head and 16.4 ft (5 m) cable,
the thread varies based on the model.
9.8 feet
(3 meters)
Typical

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Section 2. Installation and Wiring
WARNING: Explosion hazard! Do not mount the MGS-350 in an
area that may contain flammable liquids, vapors, or aerosols.
Operation of any electrical equipment in such an environment
constitutes a safety hazard.
CAUTION: The MGS-350 contains sensitive electronic
components that can be easily damaged. Do not touch nor
disturb any of these components.
NOTE: The mounting location of the monitor should allow it to be
easily accessible for visual monitoring and servicing.
NOTE: The monitor must be connected by a marked, suitably
located and easily reached switch or circuit-breaker as means of
disconnection.
NOTE: Connect monitor power and signaling terminals using
wiring that complies with local electrical codes or regulations for
the intended application.
CAUTION: An earth ground connection must be made when
using the vented metal enclosure or Exd enclosure. The safety of
this equipment is dependent on the integrity of the power supply
and the grounding of the MGS-350 enclosure.
IMPORTANT: For main PCB connections, Bacharach suggests
using one of the following:
•Belden 8761, 22 AWG single-pair shielded cable
•Belden 8450, 22 AWG individually shielded pairs
•an alarm type cable of 7/0.2 mm, 22 AWG.
NOTE: All external connections are made to the motherboard
through a cable fitting. A cable tie should be fitted within
approximately 0.75” (20
mm) of the cable gland inside the
enclosure. The connectors are plug-and-socket type, and will
accept wire of 16-22 AWG. Cable runs should be kept to a
minimum.

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NOTE: This instrument can be equipped with a semiconductor
sensor for the detection of refrigerant, combustible and VOC
gases. Semiconductor sensors are not gas specific and respond
to a variety of other gases including propane exhaust, cleaners,
and solvents. Changes in temperature and humidity may also
affect the sensor’s performance.
2.1. General Placement Guidelines
NOTE: The MGS-350 should be installed plumb and level and
securely fastened to a rigid mounting surface.
Sensors must be located within the appropriate wire lengths from the
central control unit (if used). In all cases the sensor supplied is designed
for maximum sensitivity to a particular gas. However, in certain
circumstances false alarms may be caused by the occasional presence
of sufficiently high concentrations of other gaseous impurities. Examples
of situations where such abnormalities may arise include the following:
•Plant room maintenance activity involving solvent or paint fumes
or refrigerant leaks.
•Accidental gas migration in fruit ripening/storage facilities
(bananas - ethylene, apples - carbon dioxide).
•Heavy localized exhaust fumes (carbon monoxide, dioxide,
propane) from engine-driven forklifts in confined spaces or close
to sensors.
Bacharach recommends setting the alarm delay to minimize false
alarms.
2.2. Machinery Rooms
There is no absolute rule in determining the number of sensors and their
locations. However, a number of simple guidelines will help to make a
decision. Sensors monitor a point as opposed to an area. If the gas leak
does not reach the sensor then no alarm will be triggered. Therefore, it
is extremely important to carefully select the sensor location. Also
consider ease of access for maintenance.
The size and nature of the site will help to decide which method is the
most appropriate to use. Locations requiring the most protection in a

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machinery or plant room would be around compressors, pressurized
storage vessels, refrigerant cylinders or storage rooms or pipelines. The
most common leak sources are valves, gauges, flanges, joints (brazed or
mechanical), filling or draining connections, etc.
•When mechanical or natural ventilation is present, mount a
sensor in the airflow.
•In machinery rooms where there is no discernible or strong
airflow then options are:
Point Detection, where sensors are located as near as
possible to the most likely sources of leakage, such as
the compressor, expansion valves, mechanical joints or
cable duct trenches.
Perimeter Detection, where sensors completely surround
the area or equipment.
•For heavier-than-air gases such as halocarbon and
hydrocarbon refrigerants such as R404A, propane, and butane
sensors should be located near ground level.
•For lighter-than-air gas (e.g., ammonia), the sensor needs to
be located above the equipment to be monitored on a bracket or
high on a wall within 12 in (300 mm) of (or on) the ceiling –
provided there is no possibility of a thermal layer trapped under
the ceiling preventing gas from reaching the sensor.
NOTE: At very low temperatures (e.g., refrigerated
cold store), ammonia gas becomes heavier than air.
•With similar density or miscible gases (e.g., CO or CO2), sensors
should be mounted about head high (about 5 ft [1.5 m]).
•Sensors should be positioned just far enough back from any
high-pressure parts to allow gas clouds to form and be detected.
Otherwise, a gas leak might pass by in a high-speed jet and not
be detected by the sensor.
•Make sure that pits, stairwells and trenches are monitored since
they may fill with stagnant pockets of gas.
•If a pressure relief vent (PRV) pipe is fitted to the system, it may
be a requirement to mount a sensor to monitor this vent pipe. It
could be positioned about 6 feet (2 m) above the PRV to allow
gas clouds to form.
•For racks or chillers pre-fitted with refrigerant sensors, these
should be mounted so as to monitor the compressors. If extract
ducts are fitted the airflow in the duct may be monitored.

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2.3. Refrigerated Spaces
In refrigerated spaces, sensors should be located in the return airflow to
the evaporators on a sidewall (below head-high is preferred), or on the
ceiling, not directly in front of an evaporator. In large rooms with multiple
evaporators, sensors should be mounted on the central line between 2
adjacent evaporators, as turbulence will result in airflows mixing.
2.4. Chillers
In the case of small water- or air-cooled enclosed chiller units mount the
sensor so as to monitor airflow to the extract fans. With larger models
also place a sensor inside the enclosure under or adjacent to the
compressors.
In the case of outdoor units:
•For enclosed air-cooled chillers or the outdoor unit for
variable refrigerant volume and variable refrigerant flow (VRV/VRF)
systems, mount the sensor so as to monitor airflow to the extract fan.
With large units also place a sensor inside the enclosure under or
adjacent to the compressors.
In the case of non-enclosed outdoor units:
•If there is an enclosed machinery section locate a sensor there.
•In the case of units with enclosed compressors, mount sensors in the
enclosures.
•Where you have protective or acoustic panels mount the sensor low
down under the compressors where it is protected by the panels.
•With air-cooled chillers or air-cooled condensers with non-enclosed
condenser sections it is difficult to effectively monitor leaks in the coil
sections. With some designs it will be possible using an airflow
sensor to monitor airflow to the start–up fans in the front or rear
sections.
•If there is a possibility of refrigerant leaks into a duct or air-handling
unit install a sensor to monitor the airflow.
Weatherproof sensors should be used for unprotected outdoor
applications.

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2.5. Air Conditioning (Direct Systems VRF/VRV)
For compliance with EN378, at least one detector shall be installed in
each occupied space being considered and the location of detectors
shall be chosen in relation to the refrigerant and they shall be located
where the refrigerant from the leak will collect. In this case refrigerants
are heavier than air and detectors should have their sensors mounted
low, e.g., at less than bed height in the case of a hotel or other similar
Category Class A spaces. Ceilings or other voids if not sealed are part of
the occupied space.
CAUTION: Monitoring ceiling voids in a hotel room would
not strictly comply with EN378.
Do Mount In-Room Sensors… Don’t Mount Sensors…
…at less than the normal heights of the
occupants. E.g., in a hotel room this is
less than bed height (between 8 and 20
inches [200 and 500 mm] off the floor).
…under mirrors.
…away from drafts and heat sources like
radiators, etc. …at vanity units.
… to avoid sources of steam. …in or near bathrooms.
2.6. Remote Sensor Head Installation
If you do not wish to surface mount the MGS-350, a brushed stainless
steel faceplate is available. The remote sensor is mounted in an
electrical box 1.7 in (44 mm) deep to which the vented faceplate is fitted.
CAUTION: To avoid component mix-up, do
not remove
sensor boards from multiple units at
the same time.
Alternatively, label them, or match the serial number on the
main PCB and the remote sensor PCB when reinstalling.
1. Remove the connector from the sensor PCB to feed the cable
through the housing.
2. Immediately refit the connector to the sensor board in the back of the
box. The MGS-350 and remote sensor must be kept together as they
are calibrated together and are a matched pair.

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To clean, the faceplate should be lightly dusted.
IMPORTANT: Do not spray chemicals on the MGS-350.
2.7. Components Overview and Configuration
Figure 7. MGS-350 Connections and Key Components

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Item Description
LEDs
LED 1 Green Power Status
LED 2 Red Software Check (2-second flash)
Relay 2 High-level alarm
LED 3 Yellow Software Check (2-second flash)
Relay 1 Low-level alarm
CON1
Input supply voltage and consumption (see below).
Supply voltages to be either:
•12 to 24 VAC or
•12 to 30 VDC.
CAUTION: An earth ground connection
must be made when using the vented
metal enclosure or Exd enclosure. The
safety of this equipment is dependent on
the integrity of the power supply and the
grounding of the MGS-350 enclosure.
CON2 Optional display connector
CON3 Analog Output
Pin 1: 0 V
Pin 2: 4-20 mA Load resistance < 400 Ω
Pin 3: 0-10 V Load resistance > 10 KΩ
Pin 4: 0-5 V Load resistance > 10 KΩ
CON4 Daughter board plug-in connection (installed in factory)
CON5 RS-485 Interface for connection to controller.
Pin 1: RS-485 “A”
Pin 2: RS-485 “B”
Pin 3: Common (shield)
For the communications cable, use a minimum 2
conductor with a common drain wire (screen).Set
address through address switches S2 and S3.
CON6 Relay 1 contacts (Low-level alarm, indicated by yellow
LED3)