ENMET ISA-44-RALE-OD - Manual (Page 24)

ENMET Corporation ISA-44RALE-OD/ISA-44RAHE-OD/ISA-44E-OD
20
6.1 CO Channel Calibration
MATERIALS:
q
cylinder of 20 ppm CO (high level alarm concentration)
q
cylinder of 19.5% oxygen (oxygen alarm concentration)
q
small screwdriver
q
digital voltmeter
q
ENMET calibration fixture (ENMET part no. 03605-001)
Figure 7: Control Unit CO Channel
PROCEDURE:
W ARNING : Area must be declassified during this procedure.
1. If necessary, unscrew the clear plastic bottle of the humidifier and fill to the line with clean water. Replace bottle
onto humidifier.
2. Attach the calibration fixture to high-level CO alarm gas (20 ppm CO).
3. Remove the sample head assembly from the compressed air line, and attach the quick release fitting of the
calibration fixture to the inlet of the sample head assembly. To do this, pull back the metal collar of the quick
release fitting, fit the calibration fixture over the sample head assembly air inlet, and release the collar.
4. Slowly open the valve of the calibration fixture until the gauge on the sample head assembly reaches 5 to 10 PSI.
5. Allow the gas to flow over the sensor for 5 to 7 minutes.
6. After 5 - 7 minutes, adjust the meter/gain potentiometer R33 (on CO channel circuit board) until the reading on the
CO meter of the display plate corresponds to the concentration of the low alarm point.
7. While the gas is still flowing, slowly adjust the low level alarm set potentiometer R35 (on CO channel circuit
board) until the amber alarm LED just barely activates. Be precise; you are setting the low alarm point. If the low
alarm LED is already on, adjust potentiometer R35 until the channel comes out of alarm, then readjust very slowly
until the alarm LED just barely triggers.
8. Adjust R33 gain potentiometer just until the high alarm point is reached.
9. If the LED did not activate, adjust R34 (on CO channel circuit board) until the LED just activates.
10. Using the regulator on the calibration fixture, turn off the gas. Wait until the pressure gauge on the sample head
assembly reads zero, then remove the calibration fixture and gas. Reattach sample head to air line. Meter should
go down. CO channel calibration complete.
C AUTION : If sensor fails to respond correctly or fails to clear follow steps a and b below.
CO M ETER
Low Alarm R35
R33 Meter/Gain
R32 Heater
R38 Purge
Test Point
Black
Test Point
Red
High Alarm R34
Test Point
Heater Red
Purge LED
Red
Fault LED
Red
Power LED
Green
High Alarm LED
Red
Low Alarm LED
Amber
35 34 33 32 38