Bubble found on compression

[TimB]

This morning I went to clean out my column, and it went fine. However, now I am getting a "Bubble found on compression" error message on the display of my Waters 2695 HPLC. I tried wet priming with fresh acetonitrile/water mobile phases, what I use 80% of the time, but no luck. Should I switch to 100% MeOH and try wet priming again?

[grzesiek]

purged injector already?

[TimB]

This may be a more serious issue... I noticed a small leak from one of the pumps... i took off the outer black ring and the piston and now solvent is flowing out of it. The other pump looks OK.

[grzesiek]

yes, this test is useful for detecting leaks too, that was to be my next question

[TimB]

yea the injector was purged... I undid the line going into the bottom of that pump, and solvent is flowing out of it at a pretty high rate.

Is this supposed to be like this?

It's coming from the solvent mixer inlet it looks like

[grzesiek]

sorry but wiyhout seeing i cannot help you more
if you have a leak that's probably the reason why you got the bubble alert

if you cannot do sth with the leak i would suggest to call service, they probably will teach you how to deal with the problem next time better than people writing on the forum

if the solvent is lowing and the flow is set to zero, you probably should go into the panel menu and disable it, but this happens so rarely that i can't get you clear instructions so calling service (thay on the other hand probably can) will be the quickest way

i hope you will succeed with the problem

[TimB]

Thanks for all your help grzesiek. I think a call to Waters is in order.

[Hollow]

yes it's normal that the mobile phase will flow when the inlet is disconnected from the pump, as long as the solvent line is immerged in the solvent reservoir.
There's a function called "Turn off GPV" (or so) in the "Diagnositc" section of the onborad-menu. This will close the GPV and prevents that solvent will flow while maintaning the flow path after the GPV.

[grzesiek]

"Turn off GPV" (or so) in the "Diagnositc" - this is it

[TimB]

I got the GPV turned off and everything and proceeded to look at the pump. The pump and seals appear to be fine. I tried purging the injector again and it keeps failing the compression check. There was an air bubble in the syringe, but i took care of that. I even tried wet priming with MeOH. Nothing. Still giving me the same errors when I go to start the flow.

(Most of this was done with Waters on the phone). I think I need a visit from a service engineer.