From: Steve Summit <scs@eskimo.com>
Date: Tue, 16 Jul 2002 15:14:24 -0400
Message-Id: <2002Jul16.0940.scs.0016@box16.scs.ndip.eskimo.net>
To: in-house-pikans@mit.edu, summer-pikans@mit.edu
Subject: sterilizer status
Cc: scs@eskimo.com

So there were two things wrong with the sterilizer.  One was that
the drain was clogged, such that the water level rose and rose
until it spilled over the front lip.  The other was (and still
is) that the drain cycle does not operate.

The clog was not, as I'd first suspected, in the U-trap at the
bottom (that is, down near the floor).  Rather, it was in the
vertical drain pipe, as a matter of fact mostly near the top of
the vertical drain pipe, and was nothing more than an incredible
conglomeration of scale, that semihard, semibrown, semicalcinaceous
substance that seems to plate out on surfaces which are continually
bathed in hot tap water.

With that clog at least partially reamed out, the overflow drain
works correctly, and the water level shouldn't get too high
during the course of a session.  But it looks like it will still
be necessary to drain the thing manually for a while, until we
can get the drain cycle fixed.

The scale encrustation on the whole sterilizer is pretty
incredible.  I think there's a "de-scaling" chemical we're
supposed to use once a month or so, and we should certainly
discover what it is, and get some, and use it once a day or so,
for a month or so.  I took out the bottom screen to clean it
(something I think we're supposed to do every day) and it is so
thoroughly covered with scale (only the grossest of which I was
able to remove) that water flow through it has got to be
significantly reduced.

The drain cycle is supposed to work, I think, by running the
pump motor but then opening a solenoid so that the water is not
recirculated through the spray arms, but rather diverted straight
down the drain.  At first I suspected that the drain solenoid
might have gone out, but then I realized that the motor doesn't
even try to run -- and we know the motor's okay, because it pumps
during the normal cycle.  So the likely problems are the logic
module, or simply the part of the on-off switch that initiates
the drain cycle.  The latter is more likely and should be very
easy to replace; the former might be difficult to fix and
expen$ive to replace.

[the rest of this is mostly for Chris and Rikky]

Assuming you can get a repairman in to look at it, he's likely to
be badly alarmed by the scaling.  Don't let him cow you, just say,
yeah, we fucked up, and ask him to tell you exactly what you need
and how often you should use it.  He may want to replace many
badly-scaled components; resist this.  Exception: the screen is
definitely in need of replacement (unless some clever course 5
major can figure out some particular acid to bathe it in just
strong enough to attack the scale but weak enough not to touch
the aluminum).  'Most everything else should probably be okay,
though.

If it's possible to remove the overflow drain hood so that it and
the upper end of the drain pipe can be thoroughly cleaned, that
would be a very good idea.

Both door springs need replacing.

By the time the repairman arrives, the drain cycle may or may
not need fixing (because I'm going to try to come by tonight
or tomorrow night and take another look at it), but obviously
there's enough else for him do do that it's well worth inviting
him anyway.

The repairman may have a hard time replacing the front panel,
because it bangs into the water supply line and fill solenoid
which run across the front.  If he can't get it back on, tell
him not to worry; I discovered a trick, and I can come by and do
it later.  (The trick is just to shove the pipe upwards by about
3/4 inch, from below using a big screwdriver, while fastening the
cover in place.)  If he wants to disassemble and realign the
supply line, tell him no thanks; I'm already planning to, and
I'm cheaper. :-)

One additional scale-related concern I have is that the heater
elements in the rinse tank may well be covered with the stuff,
insulating them and reducing their effectiveness and lowering
the temperature of the rinse water (or raising the time it takes
to get the rinse water up to temperature).  You might ask the
repairman about this, if it's worth removing and checking and
maybe cleaning those heater elements.  (He may want to replace
them, too, although that's likely to be *really* expen$$ive.)


Repairman aside, we should definitely figure out a way to make
sure that the bottom screen gets cleaned at least once a week or
so.  (Some disassembly is required, but it's really easy to do,
because it's designed to be, because it's supposed to be able
to be done every night, and by semiintelligent minimum-wage
graveyard shift restaurant dishwashers.  pikans should have no
problem.)  And we should also figure out a way to make sure that
the de-scaling gets done once a month, or however often it ought
to.