3M MACURCO GD-6 - Manual (Page 12)

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5. The 4-20mA output should ramp up from 4mA in clean air to 20mA at 50% LEL. See 4-20mA diagram in these User
Instructions.
note: If the 4-20ma output does not ramp up within 2 minutes, consider these possibilities:
a. Gas cylinder is empty, check the pressure gauge. Replace the gas cylinder if 25psi or less.
b. Unit needs to be re-calibrated (go through recalibration and re-test).
c. Detector is in need of servicing (return unit to factory for servicing).
d. Detector has 4-20mA option set to “OFF”. Set 4-20mA option to “On” and repeat the test.
6. Remove the gas from the sensor. Re-assemble the 3M™ Macurco™ GD-6 Combustible Gas Detector (make sure the LED
is aligned with the hole on the front of the case).
Quick Gas Test
A cigarette lighter can be used to perform a functionality test of the 3M™ Macurco™ GD-6 Combustible Gas Detector. This
test allows installers to do a quick functionality test of the gas sensor.
1. Units to be tested must be powered continuously for a minimum of 3 minutes before proceeding.
2. For optimum test results, the unit should be in clean air and be in a low ambient air flow.
3. Check that the 3M™ Macurco™ GD-6 Combustible Gas Detector status indicator light is illuminated green continuously.
If not, do not proceed with tests. See 3M™ Macurco™ GD-6 Combustible Gas Detector Trouble Indicator section in these
User Instructions.
4. The display option should be set to “On” and reading 0% LEL in clean air.
5. Aim the lighter into the sensor grate area (under “DO NOT PAINT”) on the front cover and release the gas without igniting
the flame for 2 to 3 seconds.
6. Wait for a few seconds. The digital display should climb indicating the increased gas concentration at the sensor
confirming a pass of the quick test.
note: If the Display does not change within 10 seconds, consider these possibilities:
a. Lighter is empty.
b. Unit needs to be re-calibrated (go through the Field Calibration Procedure in these User Instructions and re-test).
c. Detector is in need of servicing (return unit to factory for servicing).
7. Wait for the display to return to 0% LEL and configure options to desired settings.
Field Calibration procedure
note: For optimum calibration results the unit should be in clean air and be in a low ambient air flow.
Using a certified gas with a concentration other than the one listed for this instrument and sensor when conducting a
calibration or calibration verification test (bump test) will produce inaccurate readings. This 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, User Instructions or call 3M in U.S.A., 1-800-243-4630. In Canada, call Technical Service at 1-800-267-4414.
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Zero the Sensor
1. Remove the Philips screw on the front of the 3M™ Macurco™ GD-6 Combustible Gas Detector. Pull the front cover of the
unit off.
2. To select Calibration Zero Mode ( 000), from normal mode, press the Next button four times to get to CaL or Calibration Mode.
3. Then press the Enter button to get to “000” - Calibration Zero Mode.
4. Press the Enter button and the display will read 0 alternating with 000 (blinking) indicating zero calibration in progress
(max 165 sec).
5. If the process is successful, the display will read __0 alternating with paS (blinking) Zero Calibration complete.
6. If the process was not successful the display will read __1 alternating with Fail (blinking) Zero Failed. If this occurs, repeat
steps 2 through 4. If the sensor fails to zero twice contact Technical Assistance: 1-800-237-9049.
7. To return to Normal Mode press Enter and then press Next until “End” is displayed. Press Enter to return to Normal Mode.
Calibration
1. Remove the Philips screw on the front of the 3M™ Macurco™ GD-6 Combustible Gas Detector. Pull the front cover of the unit off.
2. Assemble the 10% LEL gas cylinder and regulator together. Ensure that the gas used for calibration matches the gas that the
3M™ Macurco™ GD-6 Combustible Gas Detector is configured to (mE, Pro or Hy).
3. Check the pressure gauge on the regulator. If you have 25psi or less you will need to replace the gas canister.
4. Place the test Hood from the regulator over the gas sensor.
5. To select Calibration Span Mode (
Spn), from normal mode, press the Next button four times to get to CaL or Calibration Mode.
6. Press the Enter button to get to “000” Calibration Zero Mode, then press the Next button to get to “Spn” - Calibration
Span Mode.