Teledyne GFC-7000T - Trace CO2 Analyzer - manual - Manual (Page 239)

Troubleshooting Model GFC7000TA Carbon Dioxide Analyzer
Teledyne Analytical Instruments 221
Table 11-1: Warning Messages – Indicated Failures (cont.)
WARNING
MESSAGE
FAULT CONDITION POSSIBLE CAUSES
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 bus
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 bus
IR photo-detector
SYSTEM RESET The computer has rebooted.
This message occurs at power on. If you have not cycled the
power on your instrument:
o
Failed +5 VDC power,
o
Fatal error caused software to restart
o
Loose connector/wiring
WHEEL TEMP
WARNING
The filter wheel temperature is
controlled at 68
 2 ° C
Blocked cooling vents below GFC Assembly. Make sure that
adequate clear space beneath the analyzer.
Analyzer’s top cover removed
Wheel heater
Wheel temperature sensor
Relay controlling the wheel heater
Entire relay board
I
2 C bus
10.1.2. 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 Section 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. Functions whose
values are still within the acceptable range but have significantly changed from the measurement
recorded on the factory data sheet may also indicate a failure. A worksheet has been provided in
Appendix C to assist in recording the value of these test functions.
Table 11-2 contains some of the more common causes for these values to be out of range.