- Pressure fluctuating from 0-600 psi with and without column.
- Priming does not help.
- Peaks are eluting late.
- Pressure dropout on plunger stroke
- Loss of pressure
- Sonicating check valves does not solve the issue
- Alliance HPLC System
- 2695/e2695/2795/2690/2790 Separations Module
- 515 HPLC Pump
- 1500 series
Faulty check valves.
FIX or WORKAROUND
- Replace the check valves with new valves of the correct type (See video below). Standard check valves, 700000254
- PerformancePLUS CV Cartridges, R/S, 1/8-in (700000254)
- Check Valve Cartridges, R/S, 1/16-in (WAT270941)
- PerformancePLUS CV Cartridge, Ceramic, 1/8-in ( 700002399)
- Check Valve, Ceramic (700002333)
- Check Valve Cartridge, R/S , Titanium (700002255)
- For 2790/2795, also replace Check Valve Cartridge, Ceramic, 1/16-in (700002761)
- If high delta psi or pressure fluctuation persists post new check valves replacement, then check system CD ratio (See video below.) If CD ratio > 1.80, consider to rebuild pump with Alliance solvent manager PM kit, 700004073.
- Confirm that no more pressure drops are present.
Replacing Alliance system Check Valve Cartridges
Checking the C/D Ratio on an Alliance 2695 HPLC