Macurco™ GD-2A
Combustible Gas Detector
User Instructions
Important: These User Instructions are to be provided to the homeowner/end user upon product
installation. Each person installing or using this equipment must read and understand the information
in these User Instructions before use. Installation of this equipment by untrained or unqualified
persons, or use that is not in accordance with these User Instructions may adversely affect product
performance and result in sickness or death. For proper use see User Instructions or call Macurco
Technical Service.
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TABLE OF CONTENTS
GENERAL SAFETY INFORMATION 4
INTENDED USE 4
LIST OF WARNINGS AND CAUTIONS 4
USE INSTRUCTIONS AND LIMITATIONS 6
USE FOR 6
DO NOT USE FOR 6
GENERAL DESCRIPTION 7
FEATURES 7
SPECIFICATIONS 7
INSTALLATION AND OPERATION INSTRUCTIONS 8
LOCATION 8
INSTALLATION 9
POWER UP 11
OPERATION 12
ALARMS 12
TROUBLE INDICATOR 13
The GD-2A is a low voltage (12-24 VAC or VDC) electronic detector of combustible, heating type
gases. The GD-2A is designed for connection to Fire Alarm/Burglary Control Panels. NOTE: Any
time the words “Control Panel” or “Alarm Panel” or “Alarm Control Panel” are used in these
instructions, they refer to a Fire Alarm/Burglary Control Panel. Alarm control panels that work on 12
or 24 VDC can provide battery backup to the GD-2A detectors. This combustible gas detector has
been evaluated by ETL for methane (natural gas) and propane (LP) gas. It is NOT designed to
detect smoke, fire or carbon monoxide.
LIST OF WARNINGS AND CAUTIONS
Each person using this equipment must read and understand the information in these User
Instructions before use. Use of this equipment by untrained or unqualified persons, or use that
is not in accordance with these User Instructions, may adversely affect product performance
and result in sickness or death.
Use only for monitoring the gas which the sensor and detector are designed to monitor. Failure
to do so may result in exposures to gases not detectable and cause sickness or death. For
proper use, see supervisor or User Instructions, or call Macurco Technical Service.
GD-2A may not function effectively below 32 F or above 120F. Using the detector outside of
this temperature range may adversely affect product performance and result in sickness or death.
This detector helps monitor for the presence and concentration level of certain specified
airborne gases. Misuse may produce an inaccurate reading, which means that higher levels of
the gas being monitored may be present and could result in overexposure and cause sickness or death. For proper use, see supervisor or User Instructions, or call Macurco Technical
Service.
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This product is intended for use in ordinary indoor locations of family living units and office
workspaces. The GD-2A is not designed to measure compliance with Occupational Safety and
Health Administration (OSHA) commercial or industrial standards.
When the unit is powered up it performs a self-test during which the green LED light will blink for
a period of one and one half to two minutes. Afterward, the green LED light will turn on
continuously to indicate the unit is in normal operation (ARMED). If the self-test fails or the
green LED light does not turn on continuously do not use. Failure to do so may adversely affect
product performance and result in sickness or death.
Immediately exit the environment if there is an alarm condition on the detector. Failure to do so
may result in sickness or death.
This detector will only indicate the presence of combustible gas at the sensor. Combustible gas
may be present in other areas. Accommodation spaces should be well ventilated when
household cleaning supplies or similar contaminants are used.
Do not cover or obstruct visual alarm LED. Doing so may adversely affect product performance
and result in sickness or death.
Do not disassemble unit or attempt to repair or modify any component of this detector. This
detector contains no user serviceable parts, and substitution of components may adversely
affect product performance and result in sickness or death.
CAUTION
Avoid the use of harsh cleaning materials, abrasives and other organic solvents. Such
materials may permanently scratch the surfaces, damage the sensor, labels or instrument
housing.
If you have any doubts about the applicability of the equipment to your job situation, consult an
industrial hygienist or call Macurco Technical Service.
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USE INSTRUCTIONS AND LIMITATIONS
Each person using this equipment must read and understand the information in these User
Instructions before use. Use of this equipment by untrained or unqualified persons, or use that is not in accordance with these User Instructions, may adversely affect product performance and
result in sickness or death.
USE FOR
The GD-2A is an electronic detector of combustible, heating type gases (natural gas and propane),
designed for connection to alarm control panels. It can operate on 12 to 24 VDC power from
standby or interruptible panel power, or be powered separately. The GD-2A is intended for
installation in buildings in non-hazardous locations such as residences, retail stores, office
buildings, and institutional buildings.
Use only for monitoring the gas which the sensor and detector are designed to monitor. Failure to
do so may result in exposures to gases not detectable and cause sickness or death. For proper
use, see supervisor or User Instructions, or call Macurco Technical Service.
DO NOT USE FOR
The GD-2A is NOT intended for use in industrial applications such as refineries, chemical plants,
etc. The GD-2A does NOT detect carbon monoxide. Do NOT mount the GD-2A in a corner. The
GD-2A is designed for connection to Fire Alarm/Burglary Control Panels. Do not connect the GD2A to Fire Alarm Circuits, or Burglar Alarm or other signals. The Alarm Control Panel must be
dedicated to gas detection or have alarm devices that provide a distinctive alarm for gas detection.
Do NOT mount the GD-2A in kitchens or bathrooms - alcohol’s, ammonia, cleaning solvents, paint
thinner, gasoline vapors, and aerosol propellants (aerosol cans such as hair spray usually contain
a combustible gas) may cause nuisance alarms.
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GD-2A may not function effectively below 32 F or above 120F. Using the detector outside of this
temperature range may adversely affect product performance and result in sickness or death.
GENERAL DESCRIPTION
The GD-2A is a low voltage (12-24 VAC or VDC) electronic detector of combustible, heating type
gases, that has been evaluated by ETL for methane (natural gas) and propane (LP) gas. The GD2A is designed for connection to Fire Alarm/Burglary Control Panels. The GD-2A has a SPDT
Alarm relay, for connection to control panels or other devices. The GD-2A does NOT detect carbon
monoxide. The GD-2A does not have an internal audible sounder.
FEATURES
Listed to UL standard 2075 for the standard for safety for gas and vapor detectors and sensors
Sensitivity tested based on UL 1484 standard for residential gas detectors
Detects heating gases: propane (LP) and natural gas (methane)
SPDT alarm and N.C. trouble relays
Can be self-restoring or latching
Electronic sensors: no maintenance or recalibration
Temperature compensated
Simple installation and operation
Supervised sensor
SPECIFICATIONS
Size: 4 ½ X 5 X 1 5/8 inches
Shipping weight: 0.54 pound
VOLTAGE: 12 to 24 VAC or VDC
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Current (non-alarm): 45 mA @ 12 VDC, 22 mA @ 24 VDC, 65 mA @ 12 VAC, 45 mA @ 24
VAC
Current (in alarm): 70 mA @ 12 VDC, 35 mA @ 24 VDC, 100 mA @ 12 VAC, 65 mA @ 24 VAC
Color: White
Sensor maintenance: Not required
Alarm relay rating: 0.125 AMPS, 40V, 3VA
Trouble relay: 0.250 AMPS, 40V, 10VA
Operating temperature range: 32° to 120° F
Alarm set point: Per UL 1484 (25% LEL)
INSTALLATION AND OPERATING INSTRUCTIONS
The following instructions are intended to serve as a guideline for the use of the Macurco GD-2A
Combustible Gas Detector. It is not to be considered all-inclusive, nor is it intended to replace the
policy and procedures for each facility.
This detector helps monitor for the presence and concentration level of certain specified airborne
gases. Misuse may produce an inaccurate reading, which means that higher levels of the gas
being monitored may be present and could result in overexposure and cause sickness or death.
For proper use, see supervisor or User Instructions, or call Macurco Technical Service.
LOCATION
A GD-2A is usually located in each room (except kitchens or bathrooms) where there are gas
appliances or through which gas pipes pass. Do NOT mount the GD-2A in a corner. Do NOT
mount the GD-2A in kitchens or bathrooms - alcohols, ammonia, cleaning solvents, paint thinner,
gasoline vapors, and aerosol propellants (aerosol cans such as hair spray usually contain a
combustible gas) may cause alarms. Do NOT mount the GD-2A where the normal ambient
temperature is below 32° F (0° C) or exceeds 120° F (50° C).
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This product is intended for use in ordinary indoor locations of family living units and office
workspaces. The GD-2B is not designed to measure compliance with Occupational Safety and
Health Administration (OSHA) commercial or industrial standards.
INSTALLATION
1. If the gas used is natural gas (methane) mount the GD-2A on a wall about one foot down from
the ceiling. If the gas used is propane (LP), mount the GD-2A on a wall or column one foot above
the floor. Use the same spacing as for smoke detectors- 30-foot centers, 900 square feet per
detector.
2. The three part plastic case allows the GD-2A to be either surface mounted or installed over a
four-inch square or double gang electrical box, providing a near flush mount. The GD-2A snap on
front cover will need to be removed before installation. To remove it, lightly pry the front cover off of
the mounting plate (middle section) with a coin or flat screwdriver inserted into the vent at the
bottom. The cover will snap off exposing the electronics and mounting plate.
3. For flush mount, remove the 2 screws and rear cover from the mounting plate and use the
appropriate hole-pattern for installation. The four holes toward the center of the mounting plate
match the hole- pattern of a double gang electrical box. The four holes near the corners match the
pattern of a four-inch square box. Mount the GD-2A so the “TOP” marked side of the mounting
plate is at the highest side. Snap the front cover back on when finished, making sure that the lights
line up with the access holes.
4. When using the GD-2A with normally closed initiating circuits, use the Com. and N.C. alarm
relay connections.
5. See wiring diagram and information below for connections of the GD-2A.
UL 2075 Requirements - 12.4.1 Power supply leads provided for field connection shall not be
less than 6 inches (152 mm) long, provided with strain relief, and shall be no smaller than 18
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AWG (0.82 mm
2
). The insulation, when thermoplastic, shall not be less than 1/32 inch (0.8
mm) thick.
Exception No. 1: A lead is not prohibited from being less than 6 inches long when it is
evident that the use of a longer lead results in damage to the insulation.
Exception No. 2: Solid copper leads as small as 26 AWG (0.13 mm
2
) are not prohibited from
use when:
A. The current does not exceed 1 ampere for lengths up to 2 feet (61 cm) and the current
does not exceed 0.4 ampere for lengths from 2 feet up to 10 feet (3.05 m);
B. There are two or more conductors and they are covered by a common jacket, or the
equivalent; and
C. The assembled conductors comply with the requirements of the Strain Relief Tests,
Section 18.
12.4.2 Leads provided for field connection to power limited signaling circuits, such as those
employed for connection to remote signaling devices, shall not be smaller than 16 AWG (1.3
mm2), for a single conductor; 19 AWG (0.65 mm2) for two or more conductors; and 26 AWG
(0.13 mm2) for four or more conductors of a multi-conductor cable. The conductor shall be
solid, bunch tinned stranded, or stranded copper. Stranded copper wire consisting of not
more than seven strands shall be employed only for 18 AWG (0.82 mm2) and larger
conductors.
6. The GD-2A uses a full wave bridge rectifier at its power input, so that it is independent of the
polarity of the input power. It can operate on DC or AC voltages between 12 and 24 volts.
7. A switching regulator is used to efficiently match the wide input voltage range to the fixed,
internal power system. As a result the power consumption is fairly constant at about 0.75 watts in
normal operation, and 1.0 watt in alarm.
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8. The alarm control panel zone inputs must be terminated with end of line resistors (E.O.L.R.),
which are provided with the panel. The GD-2A does not have an internal audible sounder and must
be connected to a Fire Alarm/Burglary Control Panel with an audible device that provides at least
85 dB sound output.
POWER UP
When the unit is powered up it performs a self-test during which the green LED light blinks for a
period of one and one half to two minutes. Afterwards, the green LED light will turn on continuously
to indicate the unit is in normal operation (ARMED). If the self-test fails or the green LED light does
not turn on continuously do not use. Failure to do so may adversely affect product performance
and result in sickness or death.
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When power is first applied to the detector, it will go through a warm-up period of one and one half
to two minutes, during which alarms are inhibited. The green LED light will turn on and off during
the delay period. The green light will turn on continuously (ARMED) afterwards to indicate the unit
is in normal operation.
OPERATION
1. Once the GD-2A is operational (ARMED) the green light will be on continuously. If gas is
detected the red LED (ALARM) turns on and the SPDT alarm relay activates to indicate the
alarm condition.
2. In the configuration, as shipped from the factory, the GD-2A is self-restoring. When the air
clears of gas, the red light turns off and the relay switches to its normal state. A jumper wire
on the circuit board can be clipped to allow the unit to latch in upon alarm. Once latched in,
power will need to be interrupted to un-latch the alarm condition.
3. The GD-2A can be modified, either before or after installation, to have a latching output. Pull
off the cover and locate the jumper wire labeled “CLIP FOR LATCH IN” on the printed circuit
board in the upper right hand side. Clip or cut this jumper wire and separate the wire ends.
Now the unit will stay in alarm (once gas has exceeded the pre-set threshold) until the power
is interrupted. When replacing the cover, make sure the lights line up with their access holes.
4. The GD-2A has a supervisory circuit of critical functions. A trouble condition, due to failure of
a non-reliable component, results in both lights switching on and off and the normally closed
trouble relay opening. A power failure also causes the trouble relay to open.
ALARMS
Immediately exit any environment if there is an alarm condition on the detector. Failure to do so
may result in sickness or death.
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The final alarm is determined by the configuration of the control panel, with the GD-2A only
switching its relay to actuate the panel. Do not connect the GD-2A to Fire Alarm Circuits, or Burglar
Alarm or other signals. The illumination of the red (ALARM) light on the GD-2A indicates the alarm
condition. When an alarm occurs immediately evacuate the premises and seek assistance.
This detector will only indicate the presence of combustible gas at the sensor. Combustible gas
may be present in other areas. Accommodation spaces should be well ventilated when household
cleaning supplies or similar contaminants are used.
In addition to the methane (natural gas) and propane (LP) gas that it is designed to detect, the GD2A can also be affected by a broad range of combustible gases. Some of these that may cause an
alarm are: alcohol, ammonia, cleaning solvents, paint thinner, gasoline vapors, and aerosol
propellants. Aerosol cans such as hair spray usually contain a combustible gas. Always make sure
that there is adequate ventilation when you use these products. Proper location, not in kitchens or
bathrooms, will minimize alarms due to normal use of household products.
TROUBLE INDICATOR
The trouble signal is determined mostly by the configuration of the alarm panel, with the GD-2A
trouble relay only providing an open circuit for actuation. A failure of the gas-sensing element will
result in both lights turning on and off and the trouble relay opening. Failure of power supplies in
the GD-2A or a lack of power to the detector will result in the trouble relay opening. The most
common expected trouble would be a break in the wiring between the panel and the GD-2A. When
a trouble signal occurs call the alarm panel installer for assistance.
Do not cover or obstruct visual alarm LED. Doing so may adversely affect product performance
and result in sickness or death.
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MAINTENANCE
The GD-2A does not require regular maintenance. The unit uses a self-purging semi-conductor
sensor that has a long life expectancy. All service and repair of the GD-2A are to be performed by
Macurco. Macurco does not sanction any third-party repair facilities.
Do not disassemble unit or attempt to repair or modify any component of this instrument. This
instrument contains no user serviceable parts, and substitution of components may impair intrinsic
safety which may adversely affect product performance and result in sickness or death.
TESTING
Once the unit is fully operational (the green light is on steady), test the unit by directing gas from an
unlighted butane cigarette lighter into the detector near the left hand side through one of the vent
holes. It will be necessary to hold the lighter valve open for several seconds. The red light
(ALARM) will turn on, the alarm relay switches, and any devices connected should activate. The
detector should be tested regularly by using gas from an unlit cigarette lighter, as detailed above.
CLEANING
The GD-2A should be cleaned using the soft brush attachment of your vacuum cleaner. The GD2A should be tested after cleaning to ensure the unit is operating normally.
SENSOR POISONS
The gas-sensing tip in the detector is designed with extreme sensitivity to the environment. As a
result, the sensing function of the tip may deteriorate if it is exposed to a direct spray from aerosols
such as paints, silicone vapors, etc., or to a high density of corrosive gases (such as hydrogen
sulfide, sulfur dioxide) for an extended period of time.
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LIMITED WARRANTY
The Macurco GD-2A Combustible Gas Detector is warranted to be free from defective material and
workmanship for a period of two (2) years from the date of manufacture (stamped on the unit). If
any component becomes defective during the warranty period, it will be replaced or repaired free of
charge, if the unit is returned in accordance with the instructions below. This warranty does not
apply to units that have been altered or had repair attempted, or that have been subjected to
abuse, accidental or otherwise. The above warranty is in lieu of all other express warranties,
obligations or liabilities. THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR PARTICULAR PURPOSE ARE LIMITED TO A PERIOD OF TWO (2) YEARS Macurco shall
not be liable for any incidental or consequential damages for breach of this or any other warranty
express or implied arising out of or related to the use of said equipment. Manufacturer or its agent’s
liability shall be limited to replacement or repair as set forth above. Buyer’s sole and exclusive
remedies are return of the goods and repayment of the price, or repair and replacement of nonconforming goods or parts.