Frequently Asked Questions

A: This is not a problem and is normal. Any time the power is cycled it will display this. ​

A: Test points may be found on the Relay PCA.

A: The STATUS outputs do not provide a dry contact output, so you will require an external relay with 5 VDC coil. Wire the positive terminal of the relay coil to the “+” STATUS connection and the negative terminal of the relay coil to the desired STATUS output to monitor. Additionally a jumper will be needed between the “D” and ground (far right) terminals. Your relay output will then act as a dry contact for this output. ​

A: Please see the following document to view the note addressing the voltage and frequency dependent changes: voltage_frequency_change.pdf​

A: The analyzer should work as low as 198 VAC.​

A: It is recommended to make the approach frequency jumper modification to operate the unit at a different frequency. Please contact the factory for details on the appropriate part number(s) and instructions. ​

A: The valves are rated for 75 psig closed and 15 psig open.

A: If the CO2 levels are low and constant, this should be ok. If the levels vary, this would cause the reading to vary as well. ​

A: The voltage drop across the transistor is load-dependent, but is generally about 1.0-1.5 V. Since it is difficult to source relays to run at such a low coil voltage, using an external power supply instead of the internal supply to assure the relay is turned on is recommended. ​

A: The detector must see a certain threshold achieved for button to appear to initiate that calibration. In the case of zero, the reading must be under a level (e.g. 0.5 ppb) to allow a zero and for the span, the signal must fall within a range of acceptability based on the concentration. These thresholds may be configuration-dependent and can be found in the Manual Calibration section of the manual.​

A: This is fine; methane is not an interferent to the carbon monoxide reading at these levels. However, you should be sure the background is representative of the process to calibrate in any offset it creates.​

A: The relays are rated 10A @ 125 VAC and 6A @ 277 VAC ​

A: The purge pressure internal to the analyzer is normally set at about 7.5 psig manually with the purge pressure regulator. Externally this line should be supplied with 1000 cc/min (± 20%) at 30 psig (± 25%). The upper limit of the purge gas pressure alarm is 12.5 psig; the lower limit is set to 2.5 psig. ​

A: Soda lime powder.​

A: The GFC7000 does not have a flow reading on the front panel. The flow control must be provided external to the analyzer as this analyzer is designed for a flow to be pushed through rather then pulled through it. In order to monitor the flow you will need some sort of external flow meter, preferably after the analyzer.​

A: This instrument is designed to be operated at an inlet pressure slightly over atmospheric pressure. (These are "blow through" cells.)​

A: Two to three years.​

A: Nitrogen or air is fine. It just can't have any CO2 in it and should be dry -- less than 0°C dew point. ​

A: Please follow the appropriate procedure below for either VOLTAGE or CURRENT output.

VOLTAGE OUTPUT

1. From the main menu press SETUP-MORE-DIAG-ENTR-NEXT until ANALOG I/O CONFIGURATION press ENTR.

2. Press SET> 5 times.

3. The top line should read A/IN CALIBRATED: YES 

4. Press CAL to calibrate the analog inputs.

5. Press < SET 4 times.

6. The top line should read CONC_OUT_1: RANGE 5V

a. If this is the output voltage you desire then go to step 7

b. If this voltage is incorrect press EDIT and change to the output voltage desired, press ENTR and go to step 7.

7. Press EDIT, Press SET>. The top line should read CONC_OUT_1: REC OFFSET: 0mv

a. If you don’t want a recorder offset go to step 8.

b. If you want a recorder offset press EDIT. Enter the OFFSET value and press ENTR. Go to step 8.

8. Press SET>. The top line should read CONC_OUT_1: AUTO CAL: ON

a. If this says AUTO CAL ON press EDIT and turn it OFF.

b. If this says AUTO CALL OFF go to step 9.

9. Press SET>. The top line should read CONC_OUT_1: CALIBRATED: YES

10. Now place your meter on pins 1 and 2 on the rear panel analog output connector and set your meter to read mvDC.

11. Press CAL on the front panel.

12. You should have some DN and UP buttons. And the top line should be say ZERO ADJUST or something similar. 

13. The output on the meter should be as close as possible to 0mV ±0.3mV.

a. If it is not then press DN or UP until the meter reads as close as possible to 0mv

b. If it does go to step 14

14. Press ENTR.

15. The top line should now say GAIN ADJUST and you should have DN and UP buttons again. The meter should now read your full-scale voltage (i.e. 1V, 5V, 10V) you will have to change the range on the meter to read Volts instead of Mili-volts.

16. Press the DN and UP buttons until the output on the meter reads your full-scale voltage ±1mV.

17. Press ENTR

18. That channel is now calibrated.

19. Do this for all channels and ensure that you move the meter on the output connector to the proper pins.

CURRENT OUTPUT

1. From the main menu press SETUP-MORE-DIAG-ENTR-NEXT until ANALOG I/O CONFIGURATION press ENTR.

2. Press SET> 5 times.

3. The top line should read A/IN CALIBRATED: YES 

4. Press CAL to calibrate the analog inputs.

5. Press < SET 4 times.

6. The top line should read CONC_OUT_1: CURRENT

a. If you desire Current output then go to step 7

b. If you do not desire Current output press EDIT and change to the output voltage desired, press ENTR and follow the steps in the Voltage Output procedure.

7. Press EDIT, Press SET>. The top line should read CONC_OUT_1: AUTO CAL: ON

a. If this says AUTO CAL ON press EDIT and turn it OFF.

b. If this says AUTO CALL OFF go to step 8.

8. Press SET>. The top line should read CONC_OUT_1: CALIBRATED: YES

9. Now place your meter on pins 1 and 2 on the rear panel analog output connector and set your meter to read mA.

10. Press CAL on the front panel.

11. You should have some DN and UP buttons. And the top line should be say ZERO ADJUST or something similar. 

12. The output on the meter should be as close as possible to 0ma ±0.01ma (if 0-20ma output), 4ma ±0.01ma (if 4-20ma output).

a. If not then press DN or UP until the meter reads as close as possible to 0ma or 4ma.

b. If it does go to step 13

13. Press ENTR.

14. The top line should now say GAIN ADJUST and you should have DN and UP buttons again. The meter should now read your full-scale current output 20ma.

15. If it doesn’t press the DN and UP buttons until the output on the meter reads your full-scale current output of 20ma ±0.01ma.

16. Press ENTR

17. That channel is now calibrated.

18. Do this for all remaining channels that contain the Current option and ensure that you move the meter on the output connector to the proper pins for that channel.​

A: The temperature coefficient is typically less than 5 ppb/°​C.​

A: Please see the attached document: 02_039E_Downloading_New_Firmware_in​to_E_Series_Analyzers.doc​

A: Please see the attached document: GFC_7000E_Startup_Guide.doc

A: The scrubber should last for about 1 year with less then 1ppm of CO2 in the stream. This puts the scrubber around 8000ppm/hours. Please keep in mind that this is just an approximation and your results may vary. 

For the purge air it is recommended to use N2 gas. If you use air with the CO2 scrubber it will die very shortly, within days as the amount of CO2 in the air is close to 400ppm. We do not recommend using this scrubber to scrub ambient air for the purge of the analyzer. I recommend that you use N2. DO NOT USE AIR TO PURGE THE UNIT UNDER ANY CIRCUMSTANCES. ​

A: The variation that you will see with an unpurged housing is simply the ratio of the unpurged length to the total length multiplied by the variation in CO2. In this case the un purged length is about 2.5 cm, the total path length is 1503 cm, yielding a rejection ratio of about 600:1. If there is a 300 ppm variation in the ambient CO2, something that is likely due to variations in human habitation, and photosynthesis, you'll see a variation of about 0.5 ppm. If this is acceptable then it should work.​

A: 15 psi. However, this is not a working pressure. The purge and sample inlets are blow through, i.e. no restriction to vent, so the working inlet and purge pressures are under 1psi, just enough to establish flow through the unit.

A: The Lower Detectable Limit is < 5ppb​

A: There is no warning, but a loss may provide a reading error.​

A: No, the reading continues to be active. Some errors may not affect the reading, such as those involving the display, analog outputs, or potentially the sample flow.​

A: If the warning level is set to 0 psi for PURGE_PRESS_SET (LO) in VARS, that effectively turns off the warning. There is no other way to eliminate or disable the purge features. ​

A: Record all front panel TST values and take note of the temperature value. Feel the top of the bench and see if it corresponds to the temperature. For example if it reads approximately 25°C, the unit should be cool to the touch and if it reads approximately 60°C, it will be hot. If cool, navigate to the Signal I/O menu located in the DIAG menu and find where the heater can be manually controlled. Measure the 120 VAC voltage going to the heater and verify if it is being cycled when the heater is being turned on/off. If the voltage properly cycles but the bench doesn't get hot, the problem is likely the strip heater. If the 120V doesn't cycle on and off, the problem is likely the relay board. ​

A: Response time is < 60 seconds to 95% of reading change. ​

A: The GFC7001 does not need purge air. ​

A: Maintenance information is detailed in the product manual. You will need to change the front panel part particulate filter, #009690100, once a week. You will want to have a source on hand, #09550000, typical replacement is every 2 years. If it has a pump, you will want a rebuild kit PU0000022 and rebuild the pump once a year. If it has an orifice, you will want a filter, FL0000001, and replace it once a year. ​

A: These parameters are used as a temperature correction. CAL BOX TEMP was the temperature within the analyzer at the time of the last calibration, and BOX TEMP is the current analyzer temperature. The electronics adds 5 ppb for each degree Celsius the BOX TEMP parameter is above CAL BOX TEMP, correcting for the anticipated error the temperature variance will cause. ​

A: Pressure compensation is in effect at all times, including during calibration.​

A: Zero air is a gas that is similar in chemical composition to the earth's atmosphere but scrubbed of all components that might affect the analyzer's readings (specifically CO and water vapor). If the analyzer is equipped with an Internal Zero Span (IZS) or an external zero air scrubber option, it is capable of creating zero air by removing interfering compounds. If the analyzer is NOT equipped with the optional CO2 sensor, zero air should be scrubbed of CO2 as well as this gas can also have an interfering effect on CO measurements. 

​For analyzers without an IZS or external zero air scrubber option, a zero air generator with CO and water vapor removal option may be used. ​

A: The GFC series includes an integral pressure sensor and compensates for fluctuations. It does not have an integral flow meter.​