Date: Mon, 10 Aug 2009 10:58:10 -0700
Reply-To: Al Knoll <anasasi@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Al Knoll <anasasi@GMAIL.COM>
Subject: Re: Dometic 182 B Fridge- Ad Nauseum
In-Reply-To: <1ed6d210908081256m18a852e3qf0d2c1b8bce6ef5d@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Grumbling helps. Hurling insults helps. Nose to mat supplication helps.
Understanding how it works is the key.
The cooling is done by the ammonia cycle refrigeration. This closed system
takes in energy as heat. How this heat is generated is not 'known' by the
ACR. A heating coil powered by 110AC can supply the heat, a heating coil
powered by 12V can supply the heat or that little lpg/propane flame can
provide the heat. The ACR doesn't know and if it doesn't cool then it
likely will not cool under any circumstances of applied heat EG. AC/DC/LPG.
To test the effectiveness of the ACR use 110VAC and measure the operation of
the Dometic. Use a good thermometer and note the starting and steady state
environment. Steady state is where the Dometic is holding at operating
temperature for several hours. This will give you a baseline measure from
which you can determine the effectiveness of operation under DC and LPG.
The LPG burner requires maintenance over it's lifetime in order to provide a
suitable amount of heat to run the ACR. A suitable output requires a proper
mixture of the LPG. That means the right ratio of LPG and oxygen on a
steady basis to maintain the flame in the burner. For lighting the burner,
the mix must be not too lean, not too rich. Very hard to measure
empirically but fairly easy to determine. When you use the little airpump
it pumps air into the system so that the LPG will have enough oxygen to burn
cleanly. When you hold down the ignitor button it disables the flame sensor
that will stop the flow of LPG unless a flame is present. When you 'strike'
the ignitor by clicking the button it causes a small spark in the vicinity
of the LPG orifice. If the burner doesn't ignite, the flame sensor will
stop the flow of LPG as soon as you release the button. If it does ignite
it takes some time to heat the flame sensor to a proper level so that LPG
will continue to flow after you release the button.
To get this ratio you must have airflow and LPG flow, disruption or
degradation of either will put you back to the first paragraph above. 11in
of water is the recommended LPG pressure. You can measure this using a
water manometer made of clear plastic tubing and a fitting on the manifold
at the output of the regulator on the LPG tank. If you don't have suitable
regulated pressure, repair as necessary until you do. All other attempts
will be compromised if the LPT supply is below par.
Flue and burner box cleaning has been covered elsewhere.
When both the pressure and the obstructions to air flow have been resolved
you might be able to start the burner. However there is a particularly
pesky pest that seems to inhabit places where LPG can be found. It is a
tiny spider. Blowing apart the spider housing authority residences with
compressed air is recommended. Then you have a chance.
The proposed precooling with 110AC masks the airflow problem by getting
airflow through the ductwork as the heated air flow aids the ignition of the
LPG flame. Likewise using a bicycle pump on the drain tube provides
addtional airflow to get the fire going. In either case the need for such
measures indicates an airflow or lpg flow problem that must eventually be
resolved.
Karl Mullendore has much more experience that I do on maintenance and repair
of Dometic 3way refrigerators and
would likely be able to help you with your particular cooling problem.
Oh yeah, it might work better in the dark.
Pensioner
On 8/8/09, Doug Alcock <doug.alcock@gmail.com> wrote:
>
> Everyone has their oown fridge mojo. I'll spare you my complete one
> ---except for 2 comments. Lighting the stove is (as far as I'm concerned)
> only to get propane flowing --- if you've had the tank off or something.
> Turn the strove off before lighting fridge. My other tip is that the fridge
> lights better when it is on the highest propane setting. I vary the setting
> for lighting with temperature ---- only if it is really hot will I light it
> with the setting on high. (This may apply after you've pre-heated things by
> running on AC). Otherwise --- turn it down to about 3/4 or 2/3 for --- say
> 70 degrees. If it is colder --- I turn it down more than that. Once the
> fridge is lit I turn it up full blast. Your mileage may vary widely :-)
>
> Good Luck,
> Doug
>
> On Sat, Aug 8, 2009 at 12:11 AM, Melissa Mourkas <westywoman@mac.com>
> wrote:
>
> > Volks-
> >
> > The OE Dometic 182B fridge was pulled from the van, cleaned &
> > serviced this week. Ran super COLD at the shop on propane. I
> > brought her home and tried to fire up the fridge on propane this
> > afternoon. (Yes, the valve was on, the burners on the stove
> > lighted). No dice. I have to admit, I got a bit pissed off.
> > Plugged the damn thing in on 110V and went in to have dinner. Bear
> > in mind I have read all available online posts on how to start these
> > things, ad nauseum.
> >
> > Post-prandials, I went out to the van to try again. 110V had lowered
> > the temp nicely, so I knew it was working. First try, it started on
> > propane. Go figure.
> >
> > Question:
> > 1.Is it because it was dark and I could see the LED? or
> > 2. Because I pre-cooled the fridge on 110V.
> >
> > I will be on my maiden voyage tomorrow (and my trusty mechanic will
> > be in tow, how lucky am I?). But I'd really like this fridge to
> > work. After all, I dumped an '81 for this....
> >
> > Melissa Mourkas
> > 84 Westy
> >
>
>
>
> --
> http://www.dougalcock.com
>
