Chromatography Forum

Dear Experts,

I recently run into some problems with my Waters Alliance e2695 HPLC.

No matter how I set up the system, it will only pump mobile phase in bottle A. I set mobile phase to be 25% A, 25% B, 25% C and 25% D. However, B, C, and D's mobile phase never moved. Only A's mobile phase is going down.

May I ask for some suggestions?

Thanks!

Try pumping 100% A, then 100% B, etc., and actually measure the flow rate each time (time collection in a graduate cylinder). My first guess would be that the B,C, and D solenoids are stuck shut. Second guess would be plugged sinker frits. Third guess would be kinked inlet lines.

Thanks Tom,

The Flow rate is accurate. The sinkers are working fine. I am guess maybe the GPV is broken. Do you have any thoughts? Thanks.

Swap the lines (a with B) on the degasser and gpv to confirm bad GPV. Rare to have 3 solenoids stuck. Run 100% water through all if heavy salt usage on b c and d
Also flush degasser chambers or bypass with a union

I tried that and got the same results.

Swap the lines (a with B) on the degasser and gpv to confirm bad GPV. Rare to have 3 solenoids stuck. Run 100% water through all if heavy salt usage on b c and d
Also flush degasser chambers or bypass with a union

If you don't have confidence in your "wrenching" skills, it's time to get a service tech in.
If you *do* have confidence, open up the pump and switch the solenoids between the A and B channels. As long as you have the B solenoid off, check to see if it's stuck (look at the service manual to confirm the necessary voltage first!).

If you don't have confidence in your "wrenching" skills, it's time to get a service tech in.
If you *do* have confidence, open up the pump and switch the solenoids between the A and B channels. As long as you have the B solenoid off, check to see if it's stuck (look at the service manual to confirm the necessary voltage first!).

Thank you. I think it may be better to schedule an on site service.

Probably the board that runs the GPV is shot. That happens.
We has one go recently, line C was our line of "choice".

When you set it to do 25% of each line and there's no clicking to be heard, and replacing the GPV does not help, it's that board.

Probably the board that runs the GPV is shot. That happens.
We has one go recently, line C was our line of "choice".

When you set it to do 25% of each line and there's no clicking to be heard, and replacing the GPV does not help, it's that board.

Thanks. That is very helpful!

G'day Zhikaining

did you solve this problem?

Would like to hear of your progress/outcome.

cheers