ENMET ISA-44-RALE-OD - Manual (Page 21)

ISA-44RALE-OD/ISA-44RAHE-OD/ISA-44E-OD ENMET Corporation
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5.0 Rough Test 5.0 Rough Test
5.1 ISA-44RALE-OD
The rough test is performed weekly after the instrument has been installed and is operating. The test verifies the alarm
capability of the instrument in response to gas and oxygen deficiency. If the alarms do not activate as defined in the
procedure outlined below, the ISA-44RALE-OD has failed this test and must be recalibrated. The rough test can also be
used as a quick check out for ISA-RALE-OD instruments which have been shut off.
MATERIALS:
q
cylinder of 75 ppm CO
q
cylinder of 17.0% oxygen
q
ENMET calibration fixture (ENMET part no. 03605-001)
q
clean water
Figure 6: Calibration Fixture with Sample Head Assembly
PROCEDURE:
1. Insure the humidifier on the sample head assembly has clean water up to the fill mark.
2. Set the Purge/Operate/Horn-off switch to the PURGE position. Allow the instrument to purge for ½ hour.
3. After ½ hour, set the Purge/Operate/Horn-off switch to OPERATE and allow the MOS sensor to stabilize for 10
minutes.
N OTE : When switch is set to OPERATE after PURGE, the CO channel may go into alarm while the sensor is stabilizing.
4. After 10 minutes, attach the calibration fixture to the cylinder of 75 ppm CO. Make sure the valve on the calibration
fixture is in the off position. Take all necessary precautions to prevent unrestricted release of pressurized air from the
compressed air line.
5. Attach the quick release fitting of the calibration fixture to the air inlet of the sample head assembly. To do this, pull
back the metal collar of the quick release fitting, put the fitting over the air inlet, and release the collar.
6. Slowly open the valve of the calibration fixture so that gas just starts to bubble through the humidifier of the sample
head assembly. Continue to slowly open the regulator until the air flow meter of the sample head assembly reads
between 5 and 10 PSI.
Cylinder
Gas or Oxygen
Calibration
Fixture
Sample Head
Assembly