35-3010A-11 Sample-Draw Detector • 19
Maintenance
This section describes maintenance procedures. It includes preventive maintenance
procedures. This section also includes procedures to troubleshoot the sample draw
detector, replace components of the sample draw detector, and adjust the low flow setting.
Preventive Maintenance
This section describes a preventive maintenance schedule to ensure the optimum
performance of the sample draw detector. It includes daily and quarterly procedures.
Daily
1.
Verify that the pilot light is on.
2.
Verify that the flowmeter indicates a flow rate of approximately 1.2 SCFH.
If necessary use the bypass valve or flow adjust potentiometer to adjust the flow rate
to 1.2 SCFH.
3.
Verify a reading of 0%LEL for the combustible channel, 0 ppm for the H
2
S channel
(100 mV at the amp 2 test points), and background concentration for the CO
2
channel
(typical background concentration of CO
2
is about 0.04% volume depending on
location).
4.
Investigate significant changes in the display reading.
Quarterly
Calibrate the sample draw detector as described in the “Calibration” section.
Troubleshooting
The troubleshooting guide describes symptoms, probable causes, and recommended
action for problems you may encounter with the sample draw detector.
NOTE:
This troubleshooting guide describes sample draw detector problems only. See
the instruction manual for the controller if it exhibits any problems.
Fail Condition
Symptoms
•
The sample draw detector’s Fail light is on.
•
The controller is operating properly but indicates a reading well below zero on one or
more channels.
Probable Causes
•
The sample draw detector’s flow rate is too low because of an obstructed sample line,
failed pump, etc.
•
The sample draw detector is malfunctioning.
•
The sensor or transmitter wiring is disconnected or misconnected.
Recommended Action
1.
At the sample draw detector, set the correct flow rate with the bypass valve or flow
adjust potentiometer.
2.
If you cannot set the correct flow rate, check the sample lines for obstructions or kinks.
