This's been on going for months: I have to change the frit in the purge valve every week! With the purge valve opened, 5ml/min pressure will go above 30 bar after roughly a week of medium use (~150 injections)

I am using regular phosphate and acetate buffers at 25 - 50mM range. Attempts to fix the problem: Change plungers, pump seals, purge lines with 50/50 water/IPA and clean resorviors. What else could be the cause of the problem? Please help!

Phosphate buffer on chn A and solvent on channel B. The purge valve is open when you are are priming these lines at conc. that ppt the buffer.

You could look into one of these two things, also. First, to get to the purge valve frit, you have to remove a little plastic cap with a thin gold disc; if that disc is scored, damaged, etc., you could see a dramatic increase in pressure while purging - replace it. Second, you simply might have a bad purge valve altogether. Order another valve from Agilent and see if that makes a difference. If not, call Agilent Tech Support for and pick their brains. Hope this helps.

I had similiar problems before, and I agree with
what David Blais said above, but try and sonicate
the purge valve in acetonitrile for about 10 minutes. That and a methylene chloride flush of the system cleared the problem up for me.