ENMET ISA-RAL-M - Manual (Page 14)

ENMET Corporation ISA-RAL-M, ISA-RAH-M
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7.0 Maintenance 7.0 Maintenance
Since the ISA-RAL-M carbon monoxide monitor is a safety instrument, it requires periodic testing and recalibration.
Refer to Operation (Section 5.0) and Calibration (Section 6.0) sections of this manual for testing and recalibration
procedures. In addition, perform the following:
7.1 Routine Maintenance
1. Check the unit for mechanical damage or simple malfunctions, such as burned out lamps.
2. Periodically check the water level inside the humidifier and add water to the high WATER LEVEL mark.
3. With the unit operating, make sure that the regulated air pressure is between 7 and 12 PSI on the gauge.
4. When power to the unit has been disconnected for more than a few hours, purge the sensor upon reapplication of
power. It may be necessary to periodically purge the sensor of a unit monitoring an airline that has a high level of
contamination. The interval between purges depends on the level of contamination. With the unit operation, turn
the switch to PURGE ON and leave for half-hour, then return the switch to OPERATE.
7.2 Sensor Cable Replacement
If the sensor no longer responds properly to calibration gases (see section 6.0, Calibration), the entire sensor cable
assembly must be replaced.
Materials Needed:
•
ISA-RAL-M sensor cable assembly, ENMET part no. 03035-109
•
Flat-headed screwdriver
•
Two adjustable wrenches (adjust to approx. 1")
Procedure:
1.
Disconnect power to the control unit to prevent electrical shock.
2. Unscrew the two front panel latches on the right side of the control unit. Open up the control unit front panel.
3. Locate TB1-5, TB1-6 and TB1-7 inside the control unit (see Figure 5). Unscrew the sensor cable leads from
these terminals.
4. Unscrew the rounded housing of the strain relief fitting in the bottom of the control unit, and draw the sensor
cable and terminal leads out through the fitting.
5. Empty the water from the humidifier bottle of the sample head assembly.
6. Using the adjustable wrenches, unscrew the brass bushing which connects the sensor cable to either the
regulator/humidifier or the hydrocarbon filter. Insert the bushing of the new sensor cable and tighten with
wrenches using hand pressure only.
7. Insert leads of new cable assembly through strain relief fitting located at bottom of enclosure. Tighten rounded
housing of fitting.
8. Attach colored leads of cable to TB1-5 (green), TB1-6 (white) and TB1-7 (black). Tighten terminal screws
gently but securely.
9. Close front panel of control unit, and replace and tighten latches.
10. Fill humidifier bottle of sample head assembly halfway with clean water and replace.
11. Apply power to instrument and allow to operate overnight with air flowing through bubbler and over sensor.
Then calibrate the instrument (see section 6.0).
7.3 Hydrocarbon Filter Replacement
The charcoal absorption filter for hydrocarbons will need periodic replacement. The length of time between
replacement depends on the instrument usage and VOC (Volatile Organic Compounds) level in the breathing air supply.
For ISA-RAL monitors that are in continuos air streams, 24 hours, 7 days a week 365 days a year it is recommended
that the filter be replaced when any of these conditions occur:
•
At least annually
•
Any time fluid is found inside the filter
•
Any time the filter is damaged
•
If any odor is detected in the breathing mask