Individual Peak Missing On Report; Chromatogram Oversized Or Off Scale; Variable Sample Size; Variable Retention Times - ABB PGC5000 Series Service Instructions Manual

PGC5000
PGC5000 Series Service Instructions

5.6.6 Individual peak missing on report

Chromatogram indicates all peaks are present; however, the data report shows the peak to be nonexistent or unknown.
The gating in the method needs to be modified to ensure gating of the missing peak in the report. This can be done by
modifying the gate ON/OFF time in the method table.

5.6.7 Chromatogram oversized or off scale

The chromatogram or peak areas are excessively large.
Causes;
1. Wrong carrier gas. Verify the correct carrier gas is being used.
2. Splitter out of adjustment (liquid sample). Adjust splitter (if installed) per factory data sheet as necessary.
3. Sample size too large (vapor sample). Manually verify block and bleed valves are functioning, if applicable; correct as
necessary. Verify the analyzer's sample vent is not restricted. Verify sample flow into analyzer is correct.

5.6.8 Variable sample size

Variable sample size can cause a non-repeatability of peak concentrations if the peak area is varying.
Causes:
1. Fluctuating sample size (liquid sample): Verify sample flow to analyzer. Verify sample is single phase. Verify splitter vent
is unrestricted.
2. Fluctuating sample size (vapor sample): Verify block and bleed valve vent is unrestricted, if applicable. Verify sample vent
pressure is not fluctuating. Verify sample flow to analyzer is not fluctuating. Verify sample flow to analyzer is correctly set
to 100 ml maximum. Possible leak in sample inject valve.

5.6.9 Variable retention times

Variable retention times can result in non-repeatability.
Causes:
1. Varying Carrier flow rate. Verify instrument air is per specification. Check oven indicators for more details. Monitor oven
purge pressure. Possible defective air purge regulator.
2. Varying oven temperature. Verify instrument air is per specification. Check oven indicators for more details. Monitor
oven purge pressure. Possible defective air purge regulator
3. Leak in column train. Leak check analyzer.
4. Contact the ABB factory for assistance in testing the functionality of the EPC Proportional Valves as well as Pressure
Sensors in the EPC block.

5.6.10 Reduced peak size

The chromatogram or peaks have reduced in size from that of a previous analysis.
Causes:
1. Wrong carrier gas. Verify the correct carrier gas is being used.
2. Excessive sample splitting (liquid sample). Verify splitter vent flow is per factory data sheet.
3. Sample size too small. Residue in the LSV stem's sample groove (liquid sample); service LSV. Verify sample flow to
analyzer coating on walls of the sample loop (vapor sample); clean or replace sample loop.
4. Detector gain (TCD only). Check detector gain jumper and adjust if necessary. Replacement TCD may not be correctly
jumpered. Compare jumpers to original TCD and correct as necessary.
5. Check that there are no leaks present on the valves and all make/break connections.
6. Inspect CP Valve sliders (if installed) for scratches and grooves.

5.6.11 Loss of power

If X purge system is installed, analyzer power will be removed and cannot be restored until purge air is restored.
Causes:
1. Air supply shut off.
2. Purged areas have leaks. Leak check with leak detector.
3. Purge air switches are defective. Replace purge switches.
SI/PGC5000-EN, Rev B
5 Diagnostics and troubleshooting
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