Date:         Mon, 14 Jul 2008 18:41:55 -0400
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: Dometic Thermistor Function?
Comments: To: Michael Diehr <md03@XOCHI.COM>
In-Reply-To:  <EBAC6871-ABD0-40CC-ABD5-A97DE861BEF5@xochi.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 02:30 PM 7/14/2008, Michael Diehr wrote:
>It's mounted on my dometic to the top set of fins on the back of the
>unit. It's a bit loose, and I'm wondering if it's important that it
>have a thermal contact with the fin, or if it just measures ambient
>air temp?

That's a snap-switch that's supposed to be pressed against the fin to
measure fin temp.  When the fin gets up around 125F (IIRC) it starts
the fan, and when it gets down around 110F it shuts off.  It's been a
while since I've looked at one, but I seem to recall that it's held
on by a very light stamped aluminum frame screwed to the fin.  If
that's true, you can bend the ears on the frame to give a solid but
light pressure against the fin.  You *could* add a tiny touch of
thermal paste at the contact spot, but thermal paste will do much
more harm than good if it's not extremely thin, and the system is
designed to work without it.

As to the fan itself, I'd personally recommend getting a Fridge-Mate
fan specifically designed for this purpose.  It turns slowly, has
large blades (a bit larger than the original, you have to be careful
about clearance to the body), is extremely quiet, and draws very
little current, similar to the original.  Compared to the little box
fan it's much quieter, uses less juice, and moves more air.  It comes
with its own air-temp sensor, but use the Dometic one on the fin
instead.  Be sure it blows up, of course.  If you look on my website
I believe you'll find a drawing of how to modify the mount for the
original fan to accomodate the Fridge-Mate.  And of course don't
forget that brown is a ground wire everywhere on the whole vehicle
EXCEPT on the fridge...

This it the fan I'm talking about:
<http://www.campingworld.com/browse/skus/index.cfm/Outdoor-and-RV-Accessories/36042/skunum=36042>
It comes with a nice little toggle switch you can use for something else, too.

david


--
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage," '85 GL "Poor Relation"