purge valve won't close?

[Laney]

I have an Agilent 1200 HPLC with quad pump. After opening the purge valve to prime, I can no longer re-direct the solvent through the system by closing the valve. Instead 90%+ of solvent continues to bypass the system and go into waste line even when purge valve appears closed tightly. I dont note any stripping of the threads on the valve knob, and it turns with a level of ease similar to before the problem. Any suggestions for fixes? I've considered replacing the valve frit, but wonder if thats really a possible culprit, since the manuals indicate a bad frit leads to increased pressure -- which I haven't seen. Thanks for advices!

[prepcolumn]

replace the valve completely..

[bisnettrj2]

I agree, sometimes purge valves fail. Agilent sells the complete assembly. You might want to disassemble the valve as much as possible and see if there isn't something in there preventing a complete seal, but I would only do that when I have a new purge valve on the instrument. Never hurts to have a backup if you find some sort of obstruction in the valve (which is doubtful, but worth a shot once you've replaced it).

[Consumer Products Guy]

New purge valve assembly. Oder two, keep one as a spare, we do.

[Johnny Rod]

Are they as rubbish as the ones on the 1100?

[Pepter]

Mine works fine. Four years of using 1200.

[carls]

Have you replaced the gold seal (PN: 5001-3707)? The "frit" is a cylidrical filter and is not part of the sealing mechanism

[Consumer Products Guy]

Are they as rubbish as the ones on the 1100?

Same.

Rule #1: don't overtighten

Rule #2: don't overtighten

Rule #3: guess !!!

[aashish_pharmacy]

Hey I also had the same problem. I use Agilent 1260 Quaternary pump. I dismantled the purge valve from the knob side by just putting the lock out. I unscrewed the whole knob out and found a lot of particles inside, I care fully cleaned it with HOT water and IPA. Assembled back. Now its working.
But do it only if u have experience over it. Make sure u dont loose any minute parts while opning the knob.