Agilent Technologies 6850 Series Service Information page 332

Table 1-4. Troubleshooting valve related chromatographic problems
Symptom
Lost peaks (degradation)
Lost or tailing peaks
Baseline perturbation
Peak tailing broad peaks
Released: April 2004
Possible cause
Valve or transfer lines too hot
Transfer line activity
Valve or transfer line too cold
Slow valve rotation
Rotor distorted
Sample/Column pressure too
different
Column overload
Flow too slow
System voids
6850 Series Gas Chromatograph Service Procedures
Solution
Reduce temperature 50°C, re-evaluate
Use nickel or Hastelloy tubing
Increase temperatures 50°C, re-evaluate
Increase actuator pressure
Replace rotor
Add back-pressure regulator to sample
drain
Use smaller sample loop
Increase split flow
Increase column flow
Increase split flow
Check connections
Reduce volume of connecting tubing
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