MERIDIAN
UNIVERSAL GAS DETECTOR
MAINTENANCE
7-28
USE AND DISCLOSURE OF DATA
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prohibited.
LCD displays CAL
REQUIRED
• Bad or weak calibration
gas.
• Poor calibration
technique.
• Replace gas source.
• Follow proper calibration procedure (refer to
).
LCD displays
UNDER RANGE
• Gas reading is below
zero.
• Interference gas present
and gives negative
reading.
• Sensor drifted.
• Re-zero in clean air.
• Check for possible interference gas.
• Re-zero and calibrate.
LCD displays
OVER RANGE
• Exposed to gas
concentration higher than
its range.
• Sensor exposed to
interference gas higher
than sensor range.
• Sensor is not settled yet,
or sensor is out of
balance.
• Check test gas verses sensor range.
• Apply clean air.
• Wait for sensor to settle. Re-balance the sensor (zero for
IR and Cat Bead sensors).
LCD displays
sensor X is
OFFLINE and fault
LED flashes
OR
LCD displays
SYSTEM FAULT
• Sensor is removed from
device.
• Sensor connection not
fully engaged.
• Replace sensor (refer to
Section 7.3.1 Replacing a Sen
-
sor
).
• Verify Sensor is pushed firmly into detector head.
LCD displays I.S.
VIOLATION and
fault LED Flashes
Sensor mapping has
changed from initial
configuration.
Re-map the sensors (refer to
).
LCD displays
SENSOR FAULT
Exposed to gas
concentration higher than its
range.
Clear the Sensor Fault (refer to
).
Table 7-7: Troubleshooting Matrix (Continued)
Symptom
Cause
Solution
