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Thermo Fisher Scientific
Malfunction
Power comes on and the
display functions, but the
pump is not running.
Table 6–2. Troubleshooting – Calibration Failures
Malfunction
Analyzer does not calibrate
properly
Cannot zero instrument or
there is a high background
signal when sampling zero
air.
Possible Cause
AC power is not reaching the
pump.
Pump is jammed due to a
new or stiff diaphragm.
Pump bearings have failed.
Possible Cause
System leak
Pressure or temperature
transducer out of calibration
Dirty system
Leaky correlation wheel
Zero air flow rate is
inadequate.
Instrument is not drawing in
span gas.
Model 48i Trace Level-Enhanced Instruction Manual
Troubleshooting
Troubleshooting Guides
Action
Deparment.
Locate the three-pin
connector on the interface
board and use a voltmeter to
check AC voltage across the
two black wires (should read
110 - 120V, even on 220V or
100V instruments).
Carefully rotate the pump
fan to get past sticking point.
Disconnect AC power and
remove the gas lines from
the pump head, then try to
rotate the pump fan. If it is
jammed, or noisy, the motor
bearings may have failed.
Action
Find and repair leak.
Recalibrate pressure and
temperature transducer.
Clean cells and flow
components.
Replace with a known good
wheel.
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.
6-3
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Troubleshooting
