Testing The Alarm Relay; Testing The 4-20Ma Loop - Macurco GD-6 Operation Manual

Macurco GD-xx Operation Manual
d. Detector has fan relay set to disable (OFF) or 20% LEL. Set fan relay to 10% LEL and repeat the test.
7. Remove the gas from the sensor. Proceed to test the alarm relay or replace the top cover.

7.3.2 Testing the Alarm Relay

Note: The gas concentration to activate the Alarm relay depends on the setting.
Connect the 20% LEL cylinder of Combustible Gas to the regulator. Ensure that the gas used for calibration matches
the gas selected in the GD-6 configuration.
1. Check the pressure gauge. If there is 25-psi or less the cylinder should be replaced.
2. Place the test hood over the gas sensor. Turn on the regulator to start the gas flow.
3. The Fan relay should activate according to the settings.
4. With the display function turned "On" and the gas concentration reaching the Alarm Relay setting, (20% LEL,
for example) the display will flash back and forth between "ALr" and "20". The buzzer will sound indicating
"Alarm" if the buzzer is turned "On". With the display function turned off the display does not show the gas
concentration but will show "ALr" when the Alarm relay is activated.
Note: If the Alarm relay fails to operate within 2 minutes, consider these possibilities:
a. Gas cylinder is empty, check the pressure gauge. Replace the gas cylinder if 25-psi or less.
b. Unit needs to be re-calibrated (go through recalibration and re-test).
c. Detector needs servicing (return unit to factory for servicing).
d. Detector has Alarm relay set to disable (OFF). Set Alarm relay to 20% LEL and repeat the test.
5. Remove the gas from the sensor after test. Proceed to test the 4-20 mA output or replace the top cover.

7.3.3 Testing the 4-20mA loop

Connect the 20% LEL cylinder of Combustible Gas to the regulator. Ensure that the gas used for calibration matches
the gas selected in the GD-6 configuration.
1. Check the pressure gauge. If there is 25-psi or less the cylinder should be replaced.
2. Place the test hood from the regulator over the gas sensor. Turn on the regulator to start the gas flow.
3. The fan relay should activate according to the settings.
4. The alarm relay should activate according to the settings.
5. The 4-20 mA output should ramp up from 4mA in clean air to 20 mA at 50% LEL. See 4-20 mA 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 25-psi or less.
b. Unit needs to be re-calibrated (go through recalibration and re-test).
c. Detector needs servicing (return unit to factory for servicing).
d. Detector has 4-20 mA option set to "OFF". Set 4-20 mA option to "On" and repeat the test.
6. Remove the gas from the sensor. Re-assemble the GD-6 (make sure the LED is aligned with the hole on the
front of the case).
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