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Subject:Re: Attn: Dometic Experts! - does the 12 volt function really work ?
From:David Beierl
Date:Tue, 22 Jul 2008 23:26:11 -0400

At 10:51 PM 7/22/2008, Scott Daniel  - Turbovans wrote:
>thanks for your good answer.
>But 'what boiler' ......is that a metaphor or what ??

Nope.  Real boiler.  See
<http://www.rvmobile.com/Tech/Trouble/coolunit.htm> for picture and
<http://www.rvmobile.com/Tech/Trouble/cooldoc.htm> for explanation of
how it all works.

>so your saying the sloshing of the amonia in the system .......or what ?

Various parts of the system contain rich ammonia solution, weak
ammonia solution, ammonia vapor, liquid ammonia, hydrogen, mixed
hydrogen and ammonia vapor -- all working in a gravity-driven
cycle.  Works best when it's not getting shaken around.  But if you
tilt it too much the cycle stops and the boiler boils dry and cakes
the chromate powder onto the boiler walls -- the sloshing around
prevents that, so you can go up long hills etc without worrying about
the fridge.

>And you are saying that any *voltage drops* that occur at the fues,
>connections etc,
>will take away from what the heater element ultimately has to work with.
>I know that's what you meant.

That's another way of saying it.  Any voltage that doesn't appear
across the heater terminals will appear somewhere else in the
circuit, and in this circuit every volt the heater doesn't see will
take away roughly 7.5 watts from the heater (and dissipate it where
that voltage *does* appear).  If it's from poor contact at the
fuse-holder, that's how you get a blown fuse without an overcurrent
condition -- the heat just melts the fuse element.

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