Teledyne gfc 7000ta operation manual Test Functions Indicated Failures

Troubleshooting Model GFC7000TA Carbon Dioxide Analyzer

Table 10-2: Test Functions - Indicated Failures

TEST

FUNCTIONS

TIME

RANGE

STABIL

CO2 MEAS

&

CO2 REF

MR RATIO

PRES

SAMPLE FL

SAMPLE

TEMP

BENCH TEMP

WHEEL TEMP

BOX TEMP

PHT DRIVE

INDICATED FAILURE(S)

Time of day clock is too fast or slow: To adjust See Section 6.6. Battery in clock chip on CPU board may be dead.

Incorrectly configured measurement range(s) could cause response problems with a Data logger or chart recorder attached to one of the analog output.

If the Range selected is too small, the recording device will over range.

If the Range is too big, the device will show minimal or no apparent change in readings.

Indicates noise level of instrument or CO2 concentration of sample gas (See Section 10.4.2 for causes).

If the value displayed is too high the IR Source has become brighter. Adjust the variable gain potentiometer on the sync/demod board

If the value displayed is too low or constantly changing and the CO2 REF is OK:

oFailed multiplexer on the mother board o Failed sync/demod board

o Loose connector or wiring on sync/demod board

Flow of purge gas to the GFC wheel housing may have stopped

If the value displayed is too low or constantly changing and the CO2 REF is BAD:

oGFC wheel stopped or rotation is too slow o Failed sync/demod board IR source

o Failed IR source o Failed relay board o Failed I2C bus

o Failed IR photo-detector

When the analyzer is sampling zero air and the ratio is too low:

oThe reference cell of the GFC wheel is contaminated or leaking.

oThe alignment between the GFC wheel and the segment sensor, the M/R sensor or both is

incorrect.

oFailed sync/demod board

oFlow of purge gas to the GFC wheel housing may have stopped When the analyzer is sampling zero air and the ratio is too high:

o Zero air is contaminated o Failed IR photo-detector

See Table 11-1 for SAMPLE PRES WARN

Check for gas flow problems. see Section 11.1.6

SAMPLE TEMP should be close to BENCH TEMP. Temperatures outside of the specified range or oscillating temperatures are cause for concern

Bench temp control improves instrument noise, stability and drift. Temperatures outside of the specified range or oscillating temperatures are cause for concern. See Table 11-1 for BENCH TEMP WARNING Wheel temp control improves instrument noise, stability and drift. Outside of set point or oscillating temperatures are cause for concern. See Table 11-1 for WHEEL TEMP WARNING

If the box temperature is out of range, check fan in the power supply module. Areas to the side and rear of instrument should allow adequate ventilation. See Table 11-1 for BOX TEMP WARNING.

If this drive voltage is out of range it may indicate one of several problems:

-A poor mechanical connection between the various components in inside the detector housing

-An electronic failure of the IR Photo-Detector’s built-in cooling circuitry, or;

-A temperature problem inside the analyzer chassis. In this case other temperature warnings would also be active such as BENCH TEMP WARNING or BOX TEMP WARNING.

Teledyne Analytical Instruments 222