You might check your particulate filters to insure correct size is being
used.
Solder resists will pass through 10 micron and larger filters.


-----Original Message-----
From: Wallisch, Ernst [mailto:[log in to unmask]]
Sent: Thursday, July 13, 2000 10:06 AM
To: [log in to unmask]
Subject: [TN] Question on D.I. system fouling


Hello Technetters,

        I am using OA paste and subsequently cleaning the CCAs in an inline
cleaner using strait D.I. water.  We have been using this process for about
5 years.   In the past year we have suddenly experienced fouling of our D.I.
water treatment system (on two separate occasions), requiring system
rebedding (not just regeneration).   The D.I. water treatment system
consists of particulate filters, carbon bed, chelate bed, cation, anion &
mixed beds.  It is a closed loop system.  The system is fed (due to vapour
loss in cleaner's exhaust ) by a separate D.I. system, which in turn is fed
by city water.  This system does not get fouled up.

        An analysis on the anion bed from the cleaner's water treatment
system resulted in the following:

                aluminum  65ppm
                iron  24 ppm
                sulphur  4200 ppm


        We have never had ppm counts like these!


        If anyone could shed some light on the reason(s) for the bed
fouling, it would be greatly appreciated.

Thank you,

Ernst Wallisch
Manufacturing Engineer
Computing Devices Canada
(Ottawa, Ontario, Canada)
(613) 596-7536

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