At 09:54 AM 8/22/2010, Dave Mcneely wrote:
>Neil, first a query:  Will the reduced clearance offset the
>advantage of the insulation?

Good point.  The RM182 was apparently designed for this specific
application, as you'll see if you look at the manual.

>  I have the Dometic installation manual.

If it has a little scribble on the cover, it's the one that came with
Dutiful Passage, my '84 Westy.

>I have not measured the temperature in that space.  However, when
>the outside temperature was over 105 F (reached 107 F that day) last
>week, and my van was in the sun, the refrigerator fan was
>running.  Someone else on here said it kicks on at 145 F.

If I'm not mistaken the spec is on at fin temp of 140F, off at
120F.  When the fridge isn't running, the fins should be at ambient.

>Why not use fiberglass bat, unfaced or with no vapor barrier
>anyway?  No problem there with either heat damaging the material (or
>worse, causing toxic outgassing), or with water vapor retention.  Dave

That's what Westfalia Werke used.  Aside from the need for better
insulation, the original is famous for trapping water which causes
the panel to rust severely and prematurely.

Foams like that are typically blown with ethane, which isn't
toxic.  The swelling occurs when the plastic softens, allowing
pressure in the (closed) cells to blow the foam a little
bigger.  Should be a one-time effect for a given max temp.

Burning *urethane* foam will kill you deader than a mackerel, so if
your seats catch fire, bail out quick.  That's what kills all the
passengers in burning airplanes.

Yours,
David