murco MGS User manual

MGS
Gas Detector
Installation and Operation Manual
Instruction 1000-0085
Revision 0 – July 2013
Product Leadership •Training •Service •Reliability

MGS Installation and Operation Manual
2 1000-0085 Rev 0
WARRANTY POLICY
MURCO 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-AUTHORISED BY OBTAINING
A RETURN MERCHANDISE AUTHORISATION (RMA) NUMBER. CONTACT THE
MANUFACTURER FOR A NUMBER AND PROCEDURES REQUIRED FOR
PRODUCT TRANSPORT.
SERVICE POLICY
MURCO MAINTAINS AN INSTRUMENT SERVICE FACILITY AT THE FACTORY.
SOME MURCO DISTRIBUTORS / AGENTS MAY ALSO HAVE REPAIR FACILITIES,
HOWEVER, MURCO ASSUMES NO LIABILITY FOR SERVICE PERFORMED BY
ANYONE OTHER THAN MURCO 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 MURCO DIRECTLY.
IF MURCO IS TO DO THE REPAIR WORK, SEND THE INSTRUMENT, PREPAID, TO
MURCO AT THE FOLLOWING ADDRESS.
MURCO
114A GEORGES STREET LOWER
DUN LAOGHAIRE
CO DUBLIN IRELAND

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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, MURCO HAS A POLICY OF PERFORMING ALL
NEEDED REPAIRS TO RESTORE THE INSTRUMENT TO FULL OPERATING
CONDITION.
PRIOR TO SHIPPING EQUIPMENT TO MURCO, CONTACT OUR OFFICE FOR AN
RMA # (RETURNED MERCHANDISE AUTHORISATION). ALL RETURNED GOODS
MUST BE ACCOMPANIED WITH AN RMA NUMBER.
PACK THE EQUIPMENT WELL (IN ITS ORIGINAL PACKING IF POSSIBLE), AS
MURCO 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
MURCO
ALL SOFTWARE USED AND/OR DISTRIBUTED BY MURCO 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 MURCO 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. Technical Specifications............................................................................ 6
Section 2. Installation and Wiring ................................................................ 8
2.1. General Placement Guidelines ................................................................. 9
2.2. Components and Access Overview .......................................................... 9
2.3. Machinery Rooms ................................................................................... 12
2.4. Refrigerated Spaces ............................................................................... 14
2.5. Chillers .................................................................................................... 14
2.6. Air Conditioning (Direct Systems VRF/VRV) .......................................... 15
Section 3. Housing Dimensions................................................................. 16
Section 4. Operation and Stabilisation...................................................... 20
Section 5. Configurations ........................................................................... 21
5.1. Overview ................................................................................................. 21
5.2. Adjusting the Alarm Set Point ................................................................. 21
Section 6. Functional Tests and Calibration............................................. 22
6.1. Introduction ............................................................................................. 22
6.2. Bump Testing .......................................................................................... 24
6.3. Calibration Overview ............................................................................... 27
6.4. Calculating Calibration Voltage ............................................................... 28
6.5. Calibrating Semiconductor (SC) Sensors ............................................... 28
6.6. Calibrating Electrochemical (EC) Sensors.............................................. 29
6.7. Calibrating Infrared (IR) Sensors ............................................................ 29
Section 7. Troubleshooting ........................................................................ 30
CE Declaration of Conformity ...................................................................... 31

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Section 1. Overview
1.1. General Information
The MGS 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).
The MGS can be used:
•in new buildings/areas that require continuous monitoring with high
tech gas sensor transmitters.
•to add gas detection solutions to an existing system.
Typical detection applications include the detection of:
•refrigerant gases
•combustible gases
•toxic gases and/or volatile organic compounds.
The MGS Controller is an optional device used to remotely monitor up to six
MGS devices. For more information, refer to the MGS Controller manual (P/N
1000-0694).
Electrochemical and Infrared Board Semiconductor Board
Figure 1. MGS Sensor Boards (EC, IR, and SC)

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1.2. Technical Specifications
Specification Description
Power Supply 12-24 VDC, 12-24 VAC 50/60 Hz, 2 W max.
Power consumption (12V): 60mA (EC), 153mA (SC), 136mA (IR)
Power Monitoring
Green LED
Visual Alarm Red LED
Audible Alarm
Buzzer, enable/disable
Fault Monitoring Red LED (on); Green LED (off)
Analogue Outputs 4-20 mA; 0-5 V; 0-10 V; 1-5 V; 2-10 V
Relay (Digital) Outputs 1 relay rated 1 A @ 24 VAC/VDC; Delay: 0, 1, 5, or 10 minutes
IP Rating
IP41 (standard); IP66 (optional)
Temperature Rating Sensor Standard Housing IP66 Housing
IR (all) -20°to 50°C -40°to 50°C
SC (all) -20°to 50°C -40°to 50°C
EC (all but NH3) -20°to 40°C -20°to 40°C
EC (0-1K ppm NH3) -20°to 40°C -40°to 40°C
Humidity Rating 0-95% non-condensing
Dimensions/Weights per
Enclosure Type (see Note
below)
Housing
Dimensions
Weight
IP41 (standard) 86 x 142 x 53 mm 180 g
IP66 (optional) 175 x 165 x 82 mm 629 g
w/ Splash Guard 175 x 225 x 82 mm 700 g
w/ Remote Sensor
175 x 155 x 82 mm
790 g
w/ Exd Sensor Head
175 x 155 x 82 mm
1185 g
w/PRV Sensor Head 175 x 155 x 82 mm 830 g
w/ Airflow/Duct 175 x 125 x 82 mm 578 g
Exd (ATEX only) 140 x 180 x 90 mm 2234 g
Standard Compliance
UL 61010-1, CSA C22.2 No. 61010-1, IEC 61010-1, EN 61010-1,
EN 55011, EN 50270, FCC Part 15, Subpart B, WEEE RoHS EuP
NOTE: The hazardous area Exd Gas Monitor products are
designed with individually certified Exd main housing enclosures and
certified Exd remote or attached sensor enclosures. The main
housing enclosure and its PCB assembly are also Exd certified, but
the final Exd Gas Monitor assemblies (main enclosure and/or
sensor assembly) are not currently Exd certified, but are pending
additional testing.

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Supported CFM/Duct Sizes for the Duct Mount Housing
Units Duct Size
Inches 12 x 12 12 x 24 18 x 18 24 x 24 24 round
Feet 1 x 1 1 x 2 1.5 x 1.5 2 x 2 Pi x 1 x 1
Area (ft2) 1 2 2.25 4 3.14
CFM Ft/min (Based on CFM and Duct Size)
2800
2800
n/a
n/a
n/a
n/a
3000 3000 n/a n/a n/a n/a
3400
3400
n/a
n/a
n/a
n/a
3800
3800
n/a
n/a
n/a
n/a
4000 4000 n/a n/a n/a n/a
4400
4400
n/a
n/a
n/a
n/a
4800
4800
n/a
n/a
n/a
n/a
5000
5000
2500
n/a
n/a
n/a
5400
5400
2700
n/a
n/a
n/a
5800
5800
2900
2578
n/a
n/a
6000
6000
3000
2667
n/a
n/a
6400
6400
3200
2844
n/a
n/a
6800
6800
3400
3022
n/a
n/a
7000
7000
3500
3111
n/a
n/a
7400
7400
3700
3289
n/a
n/a
7800
7800
3900
3467
n/a
n/a
8000
8000
4000
3556
n/a
2548
8400
8400
4200
3733
n/a
2675
8800
8800
4400
3911
n/a
2803
9000
9000
4500
4000
n/a
2866
9400
9400
4700
4178
n/a
2994
9800
9800
4900
4356
n/a
3121
10000
10000
5000
4444
2500
3185

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Section 2. Installation and Wiring
WARNING: Explosion hazard! Do not mount the MGS 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 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.
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.

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2.1. General Placement Guidelines
NOTE: The MGS 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 localised exhaust fumes (carbon monoxide, dioxide, propane)
from engine-driven forklifts in confined spaces or close to sensors.
Murco recommends setting the alarm delay to minimise false alarms.
2.2. Components and Access Overview
NOTE: The wiring is the same for the electro-chemical, semi-
conductor, and infrared models. The controller wiring is the same
for all controllers.
There is a 5-minute power-up delay to allow the sensor to stabilise. Refer to
Figure 2 and Figure 3 for internal components and wiring.

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Figure 2. EC or IR Sensor Components and Wiring

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Figure 3. SC Sensor Components and Wiring

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Item Description
Enclosure
Access
To open the standard sensor enclosure (IP41 model), turn
the cable clamp 1/2 turn counter-clockwise to loosen the
internal gland nut, depress the clip on top of the enclosure
and open. Reverse to close. (Note: For the IP66 enclosure,
use the four bolts on the front cover.)
Power 12-24V AC/DC, connect at positions 0V and +V at connector
block CN1.
•For AC: Jumper A is on, D is off. (See Figure 2 and
Figure 3.
•For DC: Jumper A is off, D is on. (Default factory setting
is DC.)
Use 2 wires, typically 18 AWG (minimum).
Output Connect two wires to terminal block CN2 positions 0V and V
or I for voltage or current, respectively.
•Connect 4-20mA at CN2 positions 0V and I
•Connect voltage output at CN2 positions 0V and V
Relay Set
Point
P1 sets the trip point for the relay and audible alarm using the
0- 5V scale (measure at test points 0V and alarm test point
TP1). Default factory setting is 50% of the range.
Time
Delay
A time delay for the operation of the relay and audible alarm
can be selected using jumpers JP5 and JP6. Default factory
setting is zero.
Audible
Alarm
The audible alarm can be disabled using jumper JP2. Default
factory setting is enabled.
2.3. 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 machinery or

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plant room would be around compressors, pressurised 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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2.4. 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.
2.5. 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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2.6. 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 an 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.

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Section 3. Housing Dimensions
Figure 4. MGS Standard Housing

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Figure 5. IP66 Housing with Splashguard

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Figure 6. IP66Airflow Duct Mount Housing
Figure 7. Exd Housing
Units = mm

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For Dimensions and Mounting Locations , See Figure 5.
Figure 8. IP66 Housing with Remote Sensor Head
NOTE: For the Exd Remote Sensor 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 4. Operation and Stabilisation
On powering up, the MGS will sense for the presence of gas after an initial
warm-up delay of 5 minutes. The green LED will flash at 1 second intervals
during the warm-up.
In an alarm condition:
•green LED stays on and the red LED is on
•audible alarm operates (if not disabled and after delay, if set).
•relay output activates (after a delay, if set)
•V and I output changes proportionally with gas concentration.
In a fault condition:
•green LED will be off and the red LED will be on
•voltage/current fault output will activate:
o2mA on the 4-20mA output
o0.5V on the 1-5V output
o1.0V on the 2-10V output.
The typical time for various sensor types to stabilise is shown below.
Sensor Type Stabilisation Time
Electrochemical (EC) 20-30 seconds
Semiconductor (SC) 1-3 minutes
Infrared (IR) 2 minutes
On power up, the electrochemical sensor outputs a signal voltage normally
below the set alarm level. Semiconductors output over the + max scale, i.e.,
> 5V. Both move towards zero as they stabilise.
If sensors have been in long-term storage or the detectors have been turned
off for a long period, stabilisation is much slower. However, within 1-2 hours
sensors should have dropped below the alarm level and be operational. You
can monitor progress exactly by monitoring the 0-10V output. When the
output settles around zero the sensor is stabilised. In exceptional
circumstances the process can take up to 24 hours or more.