Waters 600E pressure fluctuations

[dkreller]

Hello,

In the last laboratory I was working, there was a nice new Waters Alliance separations unit. If there were ever any pressure fluctuation problems, or if the unit hadn't been used for a while, it was quite straightforward to get the pressure/flow fixed up by dry and/or wet-priming.

I am in a new lab and have just started using a 600E unit that was sitting unused for about three years before it was brought back into use. We changed seals in the pumps and got reasonable performance for a while. However, after the system was not run for a few days, the pressure now fluctuates over a very large range, indicating the pump perhaps lost prime and/or there are bubbles in the pump.

I know that the 600E is a very popular and reliable model and fully expect that there are many people out there with extensive experience with it. Can anyone give me advice on how to troubleshoot and deal with this type of issue on the 600?

Thanks,

David

[juddc]

I've used both systems extensively and the 600 is a fantastic unit and amazingly reliable. It sounds like you need simply to re-prime the pump. You might wish to do this with degassed 50/50 MeOH / Water, as that's a pretty nice way to get everything wetted. I'd do a dry prime and see if that helps. If not, then one of your check valves is probably stuck. Pull the chack valve cartridges and sonicate them (I usually use 50/50 MeOH/Water or neat MeOH), then reinstall. Due to differences in design, the 600 cannot "swallow" bubbles in the lines like the Alliance can.