3M MACURCO GD-2 User Instructions

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 3M in U.S.A., 1-800-243-4630. 

In Canada, call Technical Service at 1-800-267-4414.

The GD-2A is an electronic detector of combustible gases. The GD-2A is designed 

for connection to UL Listed Fire Alarm/Burglary Control Panels. This combustible 

gas detector has been evaluated by UL for methane (natural) and propane (LP) gas. 

It is NOT designed to detect smoke, fire or carbon monoxide. 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 alarm relay activates to indicate the alarm condition at 

the control panel. In the configuration, as shipped from the factory, the GD-2A is self-

restoring meaning that when the air clears of gas, the red light turns off and the relay 

switches to its normal state. 

If you suspect a gas leak, alert others and have everyone leave immediately. 

•

Do not light a match. Do not turn lights on or off. Do not use any electrical 

switches, including a garage door opener. Do not use the telephone, 

including cell phones. The electrical current in a phone, light or electric 

switch is enough to spark an explosion. 

•

Go outside to a safe place away from the suspect area and only then call 

the gas company for help or in an emergency call 911. 

•

Stay away from your home until someone in authority tells you it is safe to 

return. 

GENERAL SAFETY INFORMATION

INTENDED USE

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 UL Listed 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 UL Listed 

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 UL 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 3M in U.S.A., 1-800-243-4630. In Canada, call 

Technical Service at 1-800-267-4414.

•  GD-2A may not function effectively below 32ºF (0ºC) or above  

120ºF (50ºC). 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 3M in U.S.A., 

1-800-243-4630. In Canada, call Technical Service at 1-800-267-4414.

•  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 3M at 1-800-243-4630. In 

Canada, call Technical Service at 1-800-267-4414.

3 

Macurco

™

Combustible Gas Detector GD-2

User Instructions for the 3M Macurco™ Combustible Gas Detector GD-2

Important:

 These User Instructions are to be provided to the homeowner/end 

user upon product installation.

3M Occupational Health and  

Environmental Safety Division

3M Center, Building 0235-02-W-70

St. Paul, MN 55144-1000

Printed in U.S.A.

3M and Macurco are trademarks of 3M.

© 2010 3M Company. All rights reserved.

98-0060-0162-6/2

34-8704-8986-0

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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 3M in U.S.A., 1-800-243-4630. In Canada, call Technical 

Service at 1-800-267-4414.

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 UL Listed Fire Alarm/

Burglary Control Panels. Do not connect the GD-2A 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 - alcohols, 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.

GD-2A may not function effectively below 32ºF (0°C) or above 120ºF (50°C). 

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 UL for methane (natural gas) and 

propane (LP) gas. The GD-2A is designed for connection to UL Listed 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 DETECTOR AND SENSORS

•  SENSITIVITY TESTED BASED ON UL 1484 STANDARD FOR RESIDENTIAL GAS 

DETECTORS

•  DETECTS HEATING GASES: PROPANE (LP), 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

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SPECIFICATIONS

•  SIZE: 4 1/2 X 5 X 1 5/8 inches

•  SHIPPING WEIGHT: 0.54 pound

•  VOLTAGE: 12 to 24 VAC or VDC

•  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: SPDT, 0.125 AMPS, 40V, 3VA

•  TROUBLE RELAY: SPST (NC), 0.250 AMPS, 40V, 10VA

•  OPERATING TEMPERATURE RANGE: 32°F to 120°F (0°C to 50°C)

•  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 

3M™ 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 3M in U.S.A., 1-800-243-4630. In 

Canada, call Technical Service at 1-800-267-4414.

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). 

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.

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. 

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