Alliance 2695 fails static leak test - WKB199238

SYMPTOMS

• The static leak test on an Alliance 2695 fail (criteria (< 600 psi/min for Firmware versions after 2.02 or < 300 psi/min for Firmware versions prior to 2.02) and compressed % volume of less than 20%)
   
• Error message during static leak test: "Accumulator unable to compress"
   
• Error message during static leak test: "Primary unable to compress"
   
• Error message during static leak test: "Accumulator leak rate ok, but lost pressure during the primary leak down testing phase"
   
• A multitude of other error messages during the static leak test
   
• Error message during static leak test (appearing at the end of the test): "Accumulator check valve failed to close"
  
  The static leak test fails for the accumulator. As the test starts, the accumulator builds pressure up to 5000 psi and then begins its leak-down period. The pressure drops at an acceptable rate, until the primary begins to compress. As the primary reaches about 3000 psi, the pressure of the accumulator drops to match the pressure of the primary. The test runs to completion, giving failing numbers for both heads.
   
• No or incorrect amount of flow delivered

ENVIRONMENT

• Alliance HPLC System
• 2695 Separations Module
• 2695D Dissolution Separations Module
• 2795 Separations Module

CAUSE

• Poor flushing of the system
• Leaking tubing and/or fittings
• Malfunctioning check valves
• Faulty prime/vent valve or check valves
• Worn metal parts inside the pump
• Worn tubings/fittings
• Failing seals inside the pump

FIX or WORKAROUND

This is a general guide to solve static leak test failures on an Alliance 2695 system. Feel free to perform only the steps necessary in your individual case to solve your pump issue.

1. Prime the system on all four channels in methanol as follows:
       a.    On a steel system with a flow rate of 10 mL/min for 6 min at least with 1 min 100% composition each channel and 2 min on 25% each.
       b.    On a peek system use double the time but half the flow rate, or the tubings might break loose.
    
2. Pressurize your system for at least 15 min with at least 3000 psi back pressure and check the delta psi to identify possible air bubbles. (You might want to give some gentle slaps with a wrench to the check valve housings if you still believe there is an air bubble inside.)
    
3. Do the static leak test and see if it passes. If the error message “X unable to compress” appears, consider replacing the check valves involved. If not, continue with point 4.
    
4. Check all pump tubings/fittings for visible leaks. If there are leaks visible, tighten or replace (find all parts in the “additional information” section).
    
5. Check if any tubings or your used pin plug look worn and/or over-bent and if they might be the problem. If they do, replace them (find all parts in the “additional information” section).
    
6. Perform the static leak test with the pin plug attached to the top transducer outlet and see if it passes. If not, continue with point 7. If it does, replace the parts needed to pass your full static leak test. This may include tubing from the top transducer to the vent valve, the vent valve itself, the tubing from vent valve to mixer, or the mixer itself (find all parts in the “additional information” section).
    
7. Disassemble the failing pump head according the Alliance control panel guidance and replace all seals. Check the seal wash housing and the high-pressure head (with the metal J-tube) for any scratches on the relevant surfaces. Have a very close look at the manifold plate as well and check for scratches or other surface altering. Also check if the tubing connected to the manifold and the check valve housings fitting look worn. Replace all parts that look faulty in any way. It is recommended that you replace the check valve housing as well as the tubing on top of the manifold whenever you replace the manifold itself, because the fittings may be faulty.
    
8. Perform the static leak test and see if it passes. If your static leak test still fails, you might have installed your new seals incorrectly. Keep a close eye on the three seals installed to the high-pressure head and make sure the middle one is pushed in tightly and straight. The outer ones should be plain with the metal plate.
    
9. Rebooting the system can help pass the test as well.

ADDITIONAL INFORMATION

Please find parts you might use to repair your pump to pass the Alliance 2695 static leak test in the following list:

Tubing:

• Standard Flow, GPV-Inlet Tubing (.030 SS) Blk (WAT270986)
• High Flow, GPV-Inlet (.040 SS) (WAT270968)
• Low Flow GPV-Inlet (.020 SS) (WAT270976)
• Tubing - Lower Transducer Accum Head (WAT270971)
• Tubing L. Head - Top Transducer (WAT270970)
• Tubing Top Transducer Vent Valve (WAT270972)
• Tubing Vent Left-In Line (WAT270974)
• Tubing Primary Head Lower Transducer (WAT270978)

Seals:

• Face Seal Replacement Kit (4/pkg) (WAT270939)
• Plunger Seal Kit - Yellow (2/pkg) (WAT270938)
• Seal Wash Plunger Seal Kit (2/pkg) (WAT271018)
• Wash Tube Seal Replacement Kit (4/pkg) (WAT270940)
• Seal Wash Face Seal Replacement Kit (WAT271017)

Other parts:

• Pressure Transducer (WAT270966)
• Prime/Vent Valve (WAT270965)
• Inline Filter Assembly (WAT035190)
• Check Valve Cartridge Housing (700002332)
• Check Valve Cartridges, R/S, 1/16-in (WAT270941)
• Check Valve Cartridge, Ceramic, 1/16-in (700002761)
• Manifold (WAT270963)
• Head Assembly w/o Seals (WAT270961)
• Seal Wash Assembly (WAT270962)
• Plunger Assembly (Standard) (WAT270959)