Date: Wed, 16 Jul 2008 13:37:54 -0400
Reply-To: David Beierl <dbeierl@ATTGLOBAL.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Beierl <dbeierl@ATTGLOBAL.NET>
Subject: Re: Dometic won't light troubleshooting
In-Reply-To: <FDF3C007-9E04-4EDC-B543-1F1B2E46DA1C@xochi.com>
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At 12:55 PM 7/16/2008, Michael Diehr wrote:
>However, left it running over night, and in the AM the temperature was
>about 60 (on 120VAC the temperature overnight was 33). Grr. :(
:-( But it runs well on AC, so you know the cooling unit is ok. Has
to be a matter of the flame. Gas pressure is first, since you can do
that without taking the fridge out again. You want 11 inches of
difference between the arms of a U-tube manometer filled with water
for operation at sea level, one or two (?) inches less for way up in
the big mountains (this is in lieu of the high-altitude orifice that
Dometic doesn't supply any more). The manometer is simply a few feet
of plastic tubing any convenient size, with the last three feet
stapled onto a board in a tall thin U half filled with water and
supported in vertical position to read. Press other end to regulator
output to measure -- the gas pressure is only a few ounces per square
inch. Approach the correct setting from below, and release the
pressure any time you turn the regulator down. Try not to
chain-smoke while doing this. <g>
If that doesn't cure it, or spread the whole works over the
landscape, you might think about getting a spare regulator and
hooking it up to a BBQ tank with fittings to make up to the fridge
directly so you can run it on the bench. Might be as much as $50 all
told, which is about what I think uninstalling and reinstalling that
thing once is worth -- not to mention the wear and tear on the
bodyside flue fitting.
>Taking a look at the flame, I see that it's blue, but with some red
>glowing part as well.
That might well be the piezo electrode in the wrong place, or it
could be the thermocouple which of course has to stick into the
flame. IIRC the thermocouple barely glows in the dark or not at all,
so prolly not it unless the flame is too big.
Next think I'd look at would be the orifice -- if you've run anything
hard through it it's probably too big; if not I'd clean it per
Dometic instruction with stove alcohol, grain alcohol from the liquor
store (can't think of the name right now, but they'll know) or
similar. I used to shove it through with a syringe IIRC.
And this is a long shot, but there's some kind of turbulence
generator in the boiler stack -- might be dimples pressed in the
sides or might be something inserted inside, I forget. If the
latter, and it's missing, the hot gases won't be hanging around as
they should to do their work.
It's possible to run the flame with the combustion box open, by the
way. A nuisance, and you can't open it far, but enough to see the
flame through.
And if that fancy silicone gasket tears or whatever, high-temp RTV
silicone gasket-maker works fine to supplement or replace it.
IIRC the pilot flame hardly exists; the working flame about the size
of a medium candle flame.
Keep the faith!
d
--
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage," '85 GL "Poor Relation"