Troubleshooting
Troubleshooting Guide
Thermo Scientific
43iQHL Instruction Manual
6-5
Problem
Possible Cause
Action
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
Check the external plumbing for
leaks or other problems.
Check all external plumbing and
the source of the sample to verify
that the SO
2
is not being absorbed
by the sampling system. Lines
carrying SO
2
must be made from
clean PTFE or stainless steel.
Detection circuit failure Run the optical span text to verify
PMT and associated electronics.
PMT failure
Check the PMT voltage. Adjust if
needed.
Flash lamp failure
Check the lamp voltage. Perform a
detector Autocal. If outside of spec,
replace the detector.
Span calibration coefficient
outside acceptable limits of
0.5–2.0.
Bad span gas
Verify quality of span gas.
System leak
Perform a leak test as described on
page
Insufficient calibrator
flow
Verify calibrator is providing a flow
of at least 1.5 LPM.
Excessive noise or spikes
on analog outputs
Defective or low
sensitivity
Check PMT voltage and run an
optical span test. Replace PMT
with known-good unit if possible.
Noise pick-up by
recorder or data logger
Check analog cable shielding and
replace.
Try to localize source of noise by
comparing analog signal to data
collected through RS-232 or
Ethernet.
Poor linearity
Problem with calibrator
Verify accuracy of the calibration
system with an independent flow
meter.
Hydrocarbon kicker
Replace kicker if older than 3 years.
Leak in sample probe
line
Check for variable dilution.
Summary of Contents for 43iQHL
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