ENMET ISA-44-RALE-OD - Manual (Page 27)

ISA-44RALE-OD/ISA-44RAHE-OD/ISA-44E-OD ENMET Corporation
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6.3.1 Routine Gas Test
PROCEDURE:
N
OTE : Units without PURGE skip steps 2, 4 & 5
1. Make sure the instrument has been in continuous operation for at least 24 hours.
2. After 24 hours, PURGE for at least 20 minutes.
3. Turn Horn off.
4. Turn PURGE off (after 20 minute purge).
5. Wait one hour to let the sensor stabilize.
6. Fill the humidifier bottle of the gas calibration fixture about half way with tap water; be sure the center tube of the
humidifier extends into the water.
7. Attach the calibration fixture to the high-level calibration gas. Set the humidifier/flowmeter upright on a level
surface.
8. Open the regulator valve slowly and adjust the flow rate. Allow a steady stream to flow through the flowmeter at a
rate of 0.9 - 1.1 scfh (standard cubic feet/hour). Do not open the valve all the way. This causes calibration errors
and quickly uses up gas.
9. Firmly place the plastic cap over the sensor.
10. Let gas flow over the sensor until verify that the alarm triggers (amber light). Use the Table 5 for approximate
lengths of time to alarm.
Table 5: Routine Gas Test Timetable
Gas of Vapor Minutes
20 ppm CO 5 to 7
50 ppm CO 5
100 ppm CO 3
200 ppm CO 2
10% LEL methane 1 to 2
20% LEL methane 1 to 2
20% LEL propane 1 to 2
100 ppm vinyl chloride 1 to 2
Typical hydrocarbon vapors 1 to 2
11. After you verify the alarm response, turn the gas off and remove the calibration fixture from the gas cylinder.
12. Using low-level calibration gas, repeat steps 8, 9 & 10 to verify the low-level alarm (amber light).
13. Follow the above steps for each channel.
14. Remove the calibration assembly from the gas cylinder.
15. Turn the Horn back on.
N OTE : If this test fails to trigger the alarms and cause appropriate meter reading, and no other electrical or mechanical
malfunction is apparent, recalibrate the device (section 6.0).