Thermo Scientific 450iQ Instruction Manual page 189

Thermo Scientific
Problem
Span calibration coefficient
outside acceptable limits of
0.5–2.0.
Excessive noise or spikes
on analog outputs
Poor linearity
Possible Cause
Instrument is not Check sample flow and pressure
drawing in sample as readings in the Settings>Health
expected 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.
Check the external plumbing for
leaks or other problems.
Check all external plumbing and
the source of the sample to verify
that the SO
absorbed by the sampling system.
Lines carrying SO
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.
Bad span gas Verify quality of span gas.
System leak Perform a leak test as described
on page 5-5.
Insufficient calibrator Verify calibrator is providing a
flow flow of at least 1.5 LPM.
Defective or low Check PMT voltage and run an
sensitivity optical span test. Replace PMT
with known-good unit if possible.
Noise pick-up by recorder Check analog cable shielding and
or data logger replace.
Try to localize source of noise by
comparing analog signal to data
collected through RS-232 or
Ethernet.
Problem with calibrator Verify accuracy of the calibration
system with an independent flow
meter.
Troubleshooting
Troubleshooting Guide
Action
or H S is not being
2 2
must be made
2
6-5
450iQ Instruction Manual