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Troubleshooting
Troubleshooting Guides
6-4
Model 48i Trace Level-Enhanced Instruction Manual
Malfunction
Instrument appears to zero,
but there is weak or no
response to span gas.
Zero or Span will not
stabilize.
Possible Cause
Internal or external lines,
filters, and other sample
handling equipment are
contaminated or dirty.
Span cylinder empty
Calibration system failure
Flow rate of the diluted span
mix is inadequate.
Instrument is not drawing in
span gas.
IR Source has failed.
Flow rate of the diluted span
mix is inadequate.
Instrument is not drawing in
span gas.
Action
Replace inlet filter (if
installed) and as much of the
tubing as possible.
Check the source pressure.
Check solenoids or other
hardware to be sure that
span gas is being delivered.
Check by-pass or
atmospheric vent to verify
that the zero air system is
providing more flow than the
instrument draws.
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 IR Source
intensity, replace source.
Check by-pass or
atmospheric pressure vent to
verify that the zero air
system is providing more
flow than the instrument is
drawing.
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.
Thermo Fisher Scientific
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Troubleshooting
