- Alliance fails compression test with 200-µL sample loop and 250-µL syringe
- Instrument passes all diagnostics using 100% methanol with 100-µL sample loop and 250-µL syringe
- Successfully adjusted seals, and measurements are within specified criteria or range
- High-pressure motor valves 1 and 2 pass leak test diagnostics
- Alliance 2695 Separations Module
Compressible volume is increased when conducting the compression test with larger sample loops.
- The parameters for the compression test were much too tight at anything below 20-psi delta decay with the larger sample loop.
FIX or WORKAROUND
- Adjust the compression test parameters according to the default parameters recommended in the operators guide.
- Recommendation: use a max delta decay of 50 psi as the default.
- Change other parameters, such as the target compression pressure, only as necessary when working with larger sample loops and/or different solvent compressibility.
- Review the compression test guidelines outlined in the following operator's guides:
Compression test passed with repeatable results with the 200-µL sample loop when delta decay was 50 psi and target compression pressure was 200 µL. This is within the acceptable range of parameters for characterizing the instrument using this diagnostic.