Date: Tue, 18 Sep 2001 22:06:34 -0700
Reply-To: Tom Moritz <tmoritz@BMI.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Tom Moritz <tmoritz@BMI.NET>
Subject: Re: info on the fridge
Content-Type: text/plain; charset="us-ascii"
Mark,
First of all, I have replaced the pale green LED with a brilliant blue LED.
Much easier to see in strong daylight. It's easy to do if you have done
any soldering on a printed circuit board in the past. The LED can be
purchased at Radio Shack. Just make sure you orient the notch on the base
of the LED the same way as the one you remove from the board. That makes
sure you have the polarity right.
Also, your comment regarding driving around a bit to facilitate lighting
the fridge reminded me I wanted to post a reason for why the fridges are
difficult to light and the way I work around this problem. First of all
you need to know that the fresh air intake and exhaust both open to
daylight at the flue cover. The loop therefore forms a U-tube and reduces
the possiblity that propane could leak into the interior of the car from
the fridge. In normal operation the hot exhaust gases from the combustion
process rises up the exhaust tube creating a vacuum that draws fresh air
down the fresh air intake.
Of course when you are trying to light the fridge for the first time there
is insufficient heat to induce the circulation. If the fridge doesn't
light the first time then the bottom of the U-tube is flooded with propane
which is much heavier than air. Too much propane won't ignite any better
than too little propane. This is where the pump comes in. By pumping air
into the bottom of the U-tube you might introduce enough oxygen to achieve
ignition. How many of you have heard a faint woomph when trying to light
your fridge? This is the sound of the excess propane igniting and rapidly
burning off. Unfortunately quite often heat is generated in both the
intake ducting as well as the flue and therefore not creating the thermal
imbalance required for proper air circulation.
What can you do to get the fridge to light more reliably? One way is to
plug your fridge in and use AC to cool the fridge. This will generate some
heat in the flue stack of the fridge which will induce enough circulation
to prevent flooding the burner chamber. You could also drive around with
the DC switch selected for the same effect.
If neither of these options are available and you can't get the burner to
light on propane try this. Make sure the fridge is NOT in propane mode.
Walk around to the flue cap and blow across it. You will probably smell
the faint oder of propane. Blow until the smell of propane is gone or for
twenty seconds, which ever is longer. Then go back and try to relight.
Blowing across the the flue causes a venturi effect and draws air through
the U-tube purging the propane and providing a fresh charge of oxygen for
combustion. If you leave the fridge in propane mode and you have a fridge
model with pulsating ignitor you could singe your nose hair when the
mixture of propane and fresh air reaches combustible proportions. I know,
it happened to me. Of course, driving around a bit will do the same thing
as blowing across the flue but my way gives the neighbors something to talk
about.
Regards,
Tom Moritz
--- original message ---
Date: Tue, 18 Sep 2001 19:46:08 EDT
From: Mark Watts <MVAone@AOL.COM>
Subject: info on the fridge
I have found it much more reliable to check the outside exhaust for heat than
to try and see if the led comes on. Pump and hold the buttton for a minute.
Then go check the vent. More than likely the fridge is working. Then wait for
dark to see if the led is bright. Also driving around the block is a lot
better than pumping the dang thing and almost always guarantees a light on
the first time.
disclaimer: this is how it works on my van YMMV ect..
Anyone else notice this?
cheers,
Mark
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