No Peaks; Double Sampling; Mystery Peaks - ABB PGC5000 Series Service Instructions Manual

PGC5000
PGC5000 Series Service Instructions
2. Contaminated or missing carrier gas, hydrogen fuel or burner air. Verify the supplied cylinders are analytical grade.
Replace cylinders one at a time; activate the pressure zones and relight the flame. Observe the baseline to isolate possible
contaminated cylinder. Replace cylinder as necessary.
3. Contaminated tubing (normally a startup issue). Locate supply cylinders as close as possible to the analyzer. Connect
them using a clean piece of tubing. Activate the pressure zones and relight the flame. Observe the baseline to isolate
possible contaminated tubing. Replace tubing as necessary.
4. Leaks. Pressure test supply lines from the source to the analyzer and pressure test the analyzer. Correct leaks as
necessary. Activate the pressure zones and relight the flame. Observe the baseline on the Manual Mode tab to verify
noise issue has been resolved.
5. Contaminated FID assembly. The FID may become contaminated due to flooding columns with liquid hydrocarbons or
running analyses with the flame out for long periods of time.
6. FID electrical failure. Disconnect the coaxial cable at the FID Amplifier assembly. Observe the baseline on the Manual
Mode tab. If baseline noise is not present, replace the coaxial cable. If it is still present reconnect the coaxial cable.
Replace the FID Amplifier assembly.
7. TCD detector balance. If the detector is not balanced between the reference and measurement filaments, balance is
needed.
8. TCD filament failure. Replace the filaments.
9. FPD baseline characterized by random noise and/or spikes. FPD noise is generally the result of electrical noise or
contamination.

5.6.3 No peaks

This generally indicates that either no sample was injected, or the injected sample is not being detected or processed.
No peak detection could be caused by any one of the following:
1. No sample flowing to the sample valve. Verify sample is flowing to the sample valve.
2. No carrier gas supplied to the analyzer. Verify air supply pressure and replace bottle as necessary.
3. No air to the sample valve actuator. Verify air supply pressure and replace bottle as necessary.
4. Baseline offset is extreme. Check for contaminated carrier, fuel and bottle, as necessary.
5. Column broken or connection in the column train is disconnected. Replace or reconnect column. Leak check analyzer and
set flows.
6. Low zone temperatures. Check system indicators for more details.
7. Analysis entries. Review analysis and correct as necessary.
8. Sample valve failure. Manual verify that valves are operating. Manually verify that solenoid valves are operating. Service
valves or replace solenoid as applicable. Replace DTC Master Digital.
9. Failed Detector Amplifier PCB.

5.6.4 Double sampling

The chromatogram peaks appear to have double apexes. The trailing peak apex is generally smaller than the leading one due to
the first having the greater sample size. Double sampling issues are isolated to the sample valve. Generally the first injection
occurs when the valve is turned on (valve stem inserted into the injection chamber). The second injection is made when the
valve is turned off (the valve stem is withdrawn from the injection chamber).
Cause: Worn liquid sample valve. Service the liquid sample valve.

5.6.5 Mystery peaks

Chromatograph displays extra peaks or a noted difference in composite chromatograph appearance from that of the
calibration.
Cause: If only present on calibration sample and not on process, verify that the correct calibration and proto fuel samples are
being analyzed. Possibly a new calibration blend has been installed that contains a blending error. Perhaps the wrong
calibration sample has been selected or incorrect analysis is attached to it.
If mystery peaks are present on all process or calibration samples, the analyzer is experiencing a sampling problem. The sample
valve seals may be leaking. The sample valve may be double sampling (see "Double Sampling"). The sample stem may be
scratched or deformed. Peaks may also be originating from a previous analysis cycle.
Check to ensure correct process stream is aligned with sample system.
SI/PGC5000-EN, Rev B
5 Diagnostics and troubleshooting
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