Date: Fri, 29 May 1998 08:41:01 8
Reply-To: Wes Neuenschwander <wesn@ESKIMO.COM>
Sender: Vanagon Mailing List <Vanagon@vanagon.com>
From: Wes Neuenschwander <wesn@ESKIMO.COM>
Subject: Re: Driving with LP appliances on
> Date: Thu, 28 May 1998 12:25:54 -0700
> From: "Steven X. Schwenk" <sxs@SCHWENK-LAW.COM>
> Subject: Re: Driving with LP appliances on
> The fridge does not go out at highway speeds. It works great. An
> unusual wind current may once a year blow mine out, but that is rare and
> not related to the speed of the vehicle.
>
While I too have been known to drive with propane on, I try avoid it when
possible, based not so much on safety concerns (though they may indeed be
valid) as on operational concerns. IMO, driving with the fridge in
propane mode raises two concerns:
1) Movement of the vehicle will cause the liquid propane in the tank to
slosh around, "slugging" the regulator with liquid propane instead of the
gaseous propane it was designed to handle. This can cause substantial -
though brief - over-pressurization in the fuel supply line to the fridge
resulting in a too-rich, sooty flame condition.
2) High speed air movement around the vehicle while traveling at
highway speed may affect the delicate supply and exhaust pressurization
differential at the refrigerator burner vent. Once again, this may affect
the air/fuel mix, causing abnormal combustion, generating excessive
soot or other combustion by-products, fouling the burner.
Both the owner's manual and Dometic service manuals make it clear that
proper ventilation is both critical and difficult to achieve. Leaks
around the vent housing, unequal lengths in the supply and exhaust tubes
or even failure to seat the burner drain valve properly are all cited as
potential causes of combustion problems. It seems reasonable to assume
that driving 50+ MPH down the highway would be at least equally perturbing
to the combustion air flow.
The net result - soot, or other by-products - from either effect will
accumulate in the burner, causing it to foul prematurely. Ultimately the
accumulation of crud in the burner results in lighting problems and
flameouts. True, easy enough to fix - just pull the unit and clean the
burner and flues. But if you're lazy (like me) or if you take it to a
dealer and pay the $100+ service charge, avoiding the problem in the
first place is perhaps not too great a price to pay for the minor
inconvenience of switching it to 12V when on the road.
-Wes
Wes Neuenschwander
Seattle, WA
wesn@eskimo.com
