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Model GFC7000E Instruction Manual TROUBLESHOOTING & REPAIR PROCEDURES
04584 Rev A1 186
Table 11-1: Warning Messages – Indicated Failures (cont.)
WARNING
MESSAGE
FAULT CONDITION POSSIBLE CAUSES
SAMPLE PRES
WARN
Sample Pressure is
<10 in-Hg or
> 35 in-Hg
Normally 29.92 in-Hg
at sea level decreasing
at 1 in-Hg per 1000 ft
of altitude (with no
flow – pump
disconnected).
If sample pressure is < 10 in-hg:
o Blocked particulate filter
o Blocked sample inlet/gas line
o Failed pressure sensor/circuitry
If sample pressure is > 35 in-hg:
o Blocked vent line on pressurized sample/zero/span gas
supply
o Bad pressure sensor/circuitry
SAMPLE TEMP
WARN
Sample temperature is
< 10
o
C or > 100
o
C.
Ambient temperature outside of specified range
Failed bench heater
Failed bench temperature sensor
Relay controlling the bench heater
Failed relay board
I
2
C buss
SOURCE
WARNING
Occurs when CO
2
Ref
is <1250 mVDC or
>4950 mVDC.
Either of these
conditions will result in
an invalid M/R ratio.
GFC wheel stopped
Failed sync/demod board
If status LED’s on the sync/demod board ARE
flashing the
cause is most likely a failed:
IR source
Relay board
I
2
C buss
IR photo-detector
SYNC WARNING Phase Lock Loop (PLL)
has lost lock on wheel
rotation.
GFC wheel stopped
GFC wheel rotation very slow/dragging
Failed sync/demod board
If status LED’s on the sync/demod board ARE
flashing the
cause is most likely an a problem with the analyzer’s main
power:
Intermittent loss of the power supply too short to cause a
SYSTEM RESET warning;
Frequency problem with the AC mains.
SYSTEM RESET The computer has
rebooted.
This message occurs at power on.
If it is confirmed that power has not been interrupted:
Failed +5 VDC power,
Fatal error caused software to restart
Loose connector/wiring
WHEEL TEMP
WARNING
The filter wheel
temperature is
controlled at 68 ± 5
°
C
Blocked Cooling Vents below GFC Assembly
Analyzer’s top cover removed
Wheel heater
Wheel temperature sensor
Relay controlling the wheel heater
Entire relay board
I
2
C buss
11.1.2. Fault Diagnosis with TEST Functions
Besides being useful as predictive diagnostic tools, the test functions viewable from the front
panel can be used to isolate and identify many operational problems when combined with a
thorough understanding of the analyzer’s theory of operation (see Chapter 10).
The acceptable ranges for these test functions are listed in the “Nominal Range” column of the
analyzer Final Test and Validation Data Sheet (p/n 04307) shipped with the instrument. Values
outside these acceptable ranges indicate a failure of one or more of the analyzer’s subsystems.