Dometic Refrigerator Repair

[austinado16]

Thought I'd post a couple of photos and a little "how to" for the archives.

I'm working on a Starcraft with a Dometic 2190 (2 way) that won't get cold.  Flame lights easily, propane pressure is right at 11" water column, propane tanks are full, lines are clear.  Flame stays lit, but after 2 hours this evening, there was barely any heat coming out of the upper louvers, and the fridge was not making cold at all.

I examined the flame and the normally seen 4 blue fingers were just a blurred blue mound.  So my flame is not making enough heat to get the boiler cooking and get the amonia boiling and expanding into hydrogen gas.

I've found that the burner box can be removed with the fridge in situ, and then the burner assembly can be removed! Very handy.

1) Remove the screws that hold the burner box to the back wall of the fridge.  I've got an 18" long philips that's great for this.  Don't worry if you drop the screws, you'll find them after step 4.

2) Carefully slide the burner box straight out, using finesse so that you don't snag and bend or damage anything....like the wire for the ignitor or the tube for the thermocouple.  You can leave the burner box attached to the corrogated paper air supply pipe, or "unscrew" it from the corragations and remove it completely (which is what I do).  It looks like this with the box removed:


3) Use a suitable wrench to hold the brass "box" where the gas line going to the burner is attached.  Use a second wrench to loosen the nut on the gas line that's screwed onto the brass "box." Spin the nut completely off the "box."  On this fridge, a 17mm(11/16") fit the "box" pretty good and a 13mm(1/2") fit the nut.  Your mileage may vary.

4) Use a screwdriver to remove the small philips head screw that you'll find facing you, and right at the base of the boiler chimney.  In other words, it's just above where the flame sort of rises into.  Remove this screw and then gently rotate the whole burner assembly back and forth while pushing it downward away from the boiler chimney.  It will move down about 1/4" and then you can swing the whole thing outward in your hand to work on it.  You'll now find any screws you dropped in step 1.

5) You can dig in further from this point and remove the thermocouple tube from the gas safety valve and unplug the wire for the ignitor.  This will allow you to completely remove the burner assembly and take it apart further, in order to get to the jet oriface, etc.  Tonight, I elected not to go further, and left the t-couple and ignitor lead hooked up.

6) Rotate the burner assembly 90 degrees so you are looking at the rounded end of the burner tube.  You'll find a tiny philips screw.  Remove it and the retaining plate it's holding.  Now you can pull out the burner tube by rocking it gently side-to-side while pulling on it.  DO NOT TOUCH THE 4 SLOTS IN THE TOP OF THE BURNER TUBE!!!!  They are very thin and will basically fall apart leaving you oh, so screwed.  

7) Remove the burner tube and clean it out inside.  In my case, when I tapped it out onto a hard surface, a bunch of rust dust fell out.  Then I shined a flashlight into the 4 slots and could see "something" in there, like maybe a white-ish spider type of nest.  I knew this was my problem.  I blew through the 4 slots with just my mouth and the burner tube came clean.

With the assembly removed,  you'll want to clean the propane jet oriface too.  Very easy.  The burner tube slid onto the front of the jet "nut" and the lazy "S" shaped gas pipe goes from that brass "box" to the rear of the jet.  So remove the gas pipe by removing it's nut, at the jet.  Then remove the 13mm(1/2") nut that holds the jet and it's metal shield to the burner assembly frame.  The jet and it's shield will now come out.  DO NOT POKE ANYTHING THROUGH THE JET ORIFACE!!  I've had good luck putting laquer thinner or carb cleaner into the jet from it's gas pipe side (there's sort of a reservoir on that side) letting it sit upright for a moment, and checking to see if the liquid will run through the oriface.  I also like to hold the oriface up to the sun to see if I can see through it.  In the case of this fridge, I couldn't really see through it very good, and the laquer thinner didn't drain out either!  Then, after the liquid has sat in there a moment, I blast the oriface out from both sides with compressed air from my air compressor.  When I held the jet up to the sky, I could definately see through it.

9) Reassembly is just the reverse of what you've done.  If you broke out your 4 burner slots, or if they were broken to begin with, find my thread for repairing them (flip the burner tube over, cut 4 new slots exactly the same is they were originally, then reinstall the burner tube, new slots facing up, and finally, pack the broken out slot area in solid with "Epoxy Steel Putty."  Good as new.

It'll look like this when you get your flame back on.  Note the nice "fat" blue fingers and how round and full they look.  If your flame doesn't look like this, it's time for a little TLC for your fridge!


UPDATE:
I've now got a good amount of heat coming out of both sides of the upper fridge louvers, nice hot-to-the-touch fridge tubes/coils, and ice cubes in the little freezer!

[Hargus]

Wow. What's tougher doing the repair or typing up the post.
Nice job though, I give you credit for tackling it.
I'm going to take a closer look at my flame.