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Purge valve question on Waters 410 RI detector

Posted: Thu Aug 09, 2018 7:44 pm
by ecigtoxdoc
What has happened when all the effluent from the detector comes out the PRG_OUT line even if Purge is set to off? Response of the detector seems to still be okay? Does anyone have a service manual for the 410? I just have the operator's manual, and purge-valve problems are not mentioned.

Re: Purge valve question on Waters 410 RI detector

Posted: Mon Aug 20, 2018 9:28 am
by gstaepels
If the eluent is coming out of the Purge line, the reference cell of the RI detector in in the solvent flow. This means that at that point the detector cannot work. The problem you have may be in the waste/recycle line. If there is a blockage (or relative high backpressure) in this line, the eluent will flow through the purge line. Check the ID of the waste/recycle line. It should have a high ID. Using a narrow ID (e.g. 0.007" or 0.012") will cause a high backpressure on the RI detector and this flow through the reference cell.
Hope this helps.