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Thermo Fisher Scientific
Malfunction
Table 6–3. Troubleshooting – Measurement Failures
Malfunction
Reduced response or no
response to sample gas with
alarm(s) indicated.
Reduced response or no
response to sample gas with
no alarms indicated.
Possible Cause
Averaging time is not set
correctly.
Possible Cause
Undefined electronic failure
or pump failure
Instrument is not drawing in
sample as expected.
Instrument is not drawing in
sample as expected.
Instrument is not properly
calibrated.
Model 48i Trace Level-Enhanced Instruction Manual
Troubleshooting
Troubleshooting Guides
Action
Check the Averaging Time in
Main Menu. If too high, the
unit will be slow to stabilize.
If too low, the signal may
appear noisy.
Action
Check alarm screens and the
diagnostic voltage screen to
localize fault.
Check the response to
known span gas.
Check sample Flow and
Pressure readings on the
Diagnostics 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 in the
"Preventive
Maintenance" chapter.
Check sample Flow and
Pressure readings on the
Diagnostics 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 in the
"Preventive
Maintenance" chapter.
Check the external plumbing
for leaks or other problems.
Go to the Calibration Factors
menu and verify that the
Background and Coefficient
are set appropriately.
6-5
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Troubleshooting
