ENMET ISA-44-RAL-OD - Manual (Page 15)

ISA-44RAL-OD / ISA-44RAH-OD ENMET Corporation
11
5.2 Oxygen Detection Channel
After installation is completed, the oxygen meter must be adjusted to a clean air reference point of 20.9% oxygen by
volume. The equipment necessary for this is included in a calibration kit for ISA-44RAL-OD / RAH-OD units, ENMET
part number 03430-001.
1. Turn operation switch to H ORN O FF position.
2. Connect the calibration fixture to the bottled clean air (20.9% oxygen) and attach the calibration fixture to the quick-
release fitting on the low pressure regulator. If you have an ISA-44RAH-OD unit, first disconnect the high-pressure
regulator attached to the incoming air line until you are finished.
3. Open the small regulator on the calibration fixture to release clean air into the sampling head assembly. Keep
opening the small regulator until the needle on the pressure guage rises to the "...SET" mark or between 7 – 12
PSI .
4. After exposing the oxygen cell to clean air for 3-5 minutes (use bottled 20.9% oxygen if necessary), dial down the
oxygen Gain Potentiometer on the front panel of the unit so that the meter needle passes the alarm point. At that
point, the amber light should go on. If the alarm does not go on at the specified oxygen alarm point, recalibrate the
oxygen channel (Section 6.2). In addition, while the unit is in alarm, turn the horn switch on briefly to verify that the
audio alarm works.
5. Dial the oxygen Gain Potentiometer up again and leave the meter at 20.9%. Before closing the small regulator on the
calibration fixture and detaching it from both the low pressure regulator and the clean air cylinder, make sure the
pressure is equalized (regulator for sample head reads zero). If you do not wait until the pressure is equalized, the
pressure will cause a backflow of water from the humidifier, which will damage the sensor.
6. The initial adjustment is complete. Turn the audio alarm back on and reattach the high pressure regulator if you have
one.
5.3 Quick Field Tests
5.3.1 Carbon Monoxide Detection Channel Field Test
To Verify The Instrument's Response Capability: Use a cylinder of high-level CO/air mixture (for example, 200 ppm
CO for a 20 ppm CO calibrated unit) with a quick-disconnect gas fixture. See Figure 5.
1. Turn operation switch to H ORN O FF position.
2. Remove the compressed air line from the sample head assembly. Insert the test gas.
3. Open the small regulator on the calibration fixture to release clean air into the sampling head assembly. Keep
opening the small regulator until the needle on the pressure gauge rises to the "...SET" mark or between 7 – 12
PSI .
4. Meter should move upscale in less than 20 seconds and read full-scale within one minute.
Whenever you use a test gas containing a level of gas greater than the calibration level, the meter swings upscale, green
power light goes out, red alarm light goes on, and relay contacts "close" to trigger any remote alarms being used.
This Test Is To Verify Response Capability; It Does Not Imply Correct Calibration. If The Test Does Not Bring
The Unit Into Alarm, Contact ENMET Personnel Or An Authorized Service Center.