Testing The Alarm Relay; Testing The 4-20Ma Loop - Macurco RD-6 Manuel D'instructions

Macurco RD-xx User Manual
5. With the display function turned "On", the RD-xx will show the current concentration of gas or "0" (zero) in clean air.
When the gas concentration reaches the Fan Relay setting (100 ppm, for example) the display will flash back and forth
between "FAn" and current gas reading.With the display function turned "OFF", the display does not show the gas
concentration but will show "FAn" as long as the fan relay is activated.
Note: If the Fan relay does not change state within 5 minutes, there are four possibilities:
a. The gas cylinder is empty, check the pressure gauge. Replace the gas cylinder if 25psi or less.
b. The detector has fan relay set to disable (diS) or higher than 600 ppm. Set fan relay to 400 ppm or less and
repeat the test.
c. The detector has fan relay delay set to 3 or more minutes. Set fan relay to 0 minutes and repeat the test.
d. The detector is in need of servicing (return unit to the factory for servicing).
6. Remove the gas from the sensor. Proceed to Test the Alarm relay or replace the top cover. Fan relay test is complete.

7.4.3 Testing the Alarm Relay

Note: The gas concentration to activate the Alarm relay depends on the setting.
1. Connect the 600ppm cylinder of Refrigerant to the regulator.
2. Check the pressure gauge. If there is 25psi or less the cylinder should be replaced.
3. Place the test hood over the gas sensor. Turn on the regulator to start the gas flow.
4. The Fan relay should activate according to the settings.
5. With the display function turned "On" and the gas concentration reaching the Alarm Relay setting, (150 ppm, for
example) the display will flash back and forth between "ALr" and current gas reading. 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 5 minutes, there are three possibilities:
a. The gas cylinder is empty, check the pressure gauge. Replace the gas cylinder if 25-psi or less.
b. The detector has Alarm relay set to disable (diS) or higher than 600 ppm. Set Alarm relay to 400 ppm and
repeat the test.
c. The detector is in need of servicing (return unit to the factory for servicing).
6. Remove the gas from the sensor after Test. Proceed to Test the 4-20mA output or replace the top cover. Alarm relay
test is complete.

7.4.4 Testing the 4-20mA loop

1. Connect the 600ppm cylinder of Refrigerant to the regulator.
2. Check the pressure gauge. If there is 25-psi or less the cylinder should be replaced.
3. Place the test hood from the regulator over the gas sensor. Turn on the regulator to start the gas flow.
4. The Fan relay should activate according to the settings.
5. The Alarm relay should activate according to the settings.
6. The 4-20 mA output should ramp up from 4mA in clean air to 9 mA at 300 ppm. See 4-20 mA diagram on page 7.
Note: If the 4-20mA output does not ramp up within 5 minutes, there are three possibilities:
a. The gas cylinder is empty, check the pressure gauge. Replace the gas cylinder if 25-psi or less.
b. The detector has 4-20 mA option set to "OFF". Set 4-20mA option to "bAS or EnH" and repeat the test.
c. The detector is in need of servicing (return unit to the factory for servicing).
7. Remove the gas from the sensor. Re-assemble the RD-xx (make sure the LED is aligned with the front case hole). 4-20
current loop test is complete.
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