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purge valve won't close?
Posted: Wed Apr 11, 2012 4:09 am
by 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!
Re: purge valve won't close?
Posted: Wed Apr 11, 2012 5:36 am
by prepcolumn
replace the valve completely..
Re: purge valve won't close?
Posted: Wed Apr 11, 2012 12:06 pm
by 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).
Re: purge valve won't close?
Posted: Wed Apr 11, 2012 3:20 pm
by Consumer Products Guy
New purge valve assembly. Oder two, keep one as a spare, we do.
Re: purge valve won't close?
Posted: Tue Apr 17, 2012 7:16 am
by Johnny Rod
Are they as rubbish as the ones on the 1100?
Re: purge valve won't close?
Posted: Tue Apr 17, 2012 12:28 pm
by Pepter
Mine works fine. Four years of using 1200.
Re: purge valve won't close?
Posted: Tue Apr 17, 2012 1:28 pm
by carls
Have you replaced the gold seal (PN: 5001-3707)? The "frit" is a cylidrical filter and is not part of the sealing mechanism
Re: purge valve won't close?
Posted: Tue Apr 17, 2012 5:02 pm
by 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 !!!
Re: purge valve won't close?
Posted: Fri Jun 01, 2012 9:52 am
by 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.