Thermo Scientific 450iQ Instruction Manual page 188

Troubleshooting
Troubleshooting Guide
6-4 450iQ Instruction Manual
Problem
Reduced response or no
response to sample gas
with alarm(s) indicated
Reduced response or no
response to sample gas
with no alarm(s) indicated
Possible Cause
Instrument is not
drawing in span gas
SO or H S is being
2 2
absorbed and released
by dirt in tubing or filters
of the calibration system
or contamination inside
the instrument
Averaging time is not
correct
Flasher lamp
Undefined electronic
failure or pump failure
Instrument is not
drawing in sample as
expected
Instrument is not
properly calibrated
Action
drawing.
Check the sample flow and
pressure in the Settings>Health
Check>Status and Alarms>Flow
and Pressure screen.
Use an independent flow meter to
check flows at the sample inlet
and exhaust bulkheads (they
should match).
Perform a leak test as described
on page 5-5.
Replace any lines made of vinyl or
plastics with fresh PTFE or
stainless steel. Replace PTFE filter
membranes that look dirty.
Remove any filters that are not
PTFE membranes.
Check the "Averaging Time" in
the Settings>Measurement
Settings screen. If too high, the
unit will be slow to stabilize. If
too low, the signal may appear to
be noisy.
Replace with known-good lamp to
see if the lamp is the problem.
Check the status and alarms
screen to localize fault.
Check the response to known
span gas.
Run an optical span test.
Check the sample flow and
pressure in the Settings>Health
Check>Status and Alarms>Flow
and Pressure screen.
Use an independent flow meter to
check flows at the sample inlet
and exhaust bulkheads (they
should match).
Perform a leak test as described
on page 5-5.
Verify the SO or H S backgrounds
2 2
and SO or H S coefficients are
2 2
set appropriately in the
Calibration screen.
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