Dometic working on shore power, but difficult to get it running on gas

[Scott J-24]

We are getting ready for a long weekend trip and I always start the refrigerator a day or two ahead to get it good and cold prior to loading the TT for the trip. It usually takes a couple of attempts to get it started (so the LP fault light doesn't flash). However, this time I have tried to re-start it 6 or 7 times and after about 10 minutes the LP fault light starts flashing. Gas is on (both tanks), burners on the range top are working, but the refrigerator wasn't getting started. I had presumed that the problem getting the refrigerator running on previous trips was due to no gas in the line and it just took awhile to fill the gas line and get it going. While trying to get it started again this morning I could hear it go whoosh, but the pilot light still didn’t appear to stay lit. I used a long nosed lighter and could hear it go whoosh again while keeping the flame on the thermal couple in an attempt to get it heated, but it still didn’t look lit. Now I am wondering if the thermal couple was starting to go bad and is now non-functional. If it is the thermal couple, how easy or difficult is it to replace myself, or is it a job best left to a repair/service tech. Worse case for this weekend, we pack a couple of coolers to use until get hooked up to shore power at the CG and the refrigerator cools down. Not my first choice, but...


Late Breaking News: Just got an e-mail from my wife, and the refrigerator is starting to get cold. But I am still concerned about the thermal couple. Is it on its last legs, or is this just normal operations? I really don't want to go through this every time we get ready for a trip.

[VIKING]

Thermocouples are usually very easy to replace if you can find a replacement in time. It could be a piece of dirt in the burner also. I would clean it before purchasing any new parts.
Best to you,
Rich the Viking

[Scott J-24]

Originally Posted by VIKING

Thermocouples are usually very easy to replace if you can find a replacement in time. It could be a piece of dirt in the burner also. I would clean it before purchasing any new parts.
Best to you,
Rich the Viking

Rich,

What is involved in cleaning the burner? Do I just remove the windscreen and clean with cloth and little soapy water? Are there any special tools or such that I will need to clean the gas lins or flue? Sorry for all the questions, but being a rookie, I am still in the learning curve.

[VIKING]

The part that gets clogged in mine is the burner orifice. It is a small brass fitting with a tiny hole for the gas to flow through. You must not damage it or ream the hole out larger than it is. Just a gentle cleaning and blowing it out was enough for mine to clear. You should be able to remove it with a wrench for cleaning.
Best to you,
Rich the Viking

[klattu]

Sometimes it is better to use a vacuum to clean, and I think the wires from a wire brush fit the last time I did this.
Also next time you have to refill tanks, start gas flow by turning on a eye at the stove... and lighting of course.

[SeeMore]

To clean the orifice, use denatured alcohol ONLY! The laser cut ruby inside the hole is easily damaged by a wire or pressurized air. Remove the brass fitting (after cutting off the propane at the tank) and soak it for 25 minutes (submerged). Let it air dry for 15-20 minutes and reinstall.

[neil.ervin]

your situation sounds just like mine is acting. I took mine to local RV repair today and of course the refrig started right up on gas. They said problem might be one of two items. (1) The unit that creates the spark (on my 2005 Safari it is to the left of the gas chamber and has a black cover with 2-3 small wires coming out. (2) or the wire delivering the spark might be bad (mine is very small, clear/white and runs to a probe beside the gas orfice. DO NOT remove the wire from the black component except with insulated plyers or you will get a really big electric shock.

With insulated plyers, remove the white/clear tube from the black unit (after removing the black cover). With the plyers, hold the black unit wire end close enough to the spot it was removed from and check that you are getting consistent sparks.

BTW, everytime your refrig reaches temp, the gas flow shuts off and must later be restarted. Thus, on initial start or restart, the failure to ignite and thus 'check' indicator can occur anytime.

Beyond that, I cannot help. The black unit retails for $35 and the wire unit for $30.

[SeeMore]

If you want to better understand and repair your Dometic Reefer download the service manual PDF here:

Dometic refrigerators - Download Dometic Manuals

[Scott J-24]

Originally Posted by dpe01

If you want to better understand and repair your Dometic Reefer download the service manual PDF here:

Dometic refrigerators - Download Dometic Manuals

Thanks for the link. This should give us what we need.

[Scott J-24]

After cleaning and blowing out the gas orifice, the refrigerator still would not light. The next step was to replace the igniter wire and probe. That did the trick, now it fires up in the first ignition cycle. One problem down and now on to the next... an intermittent leak at the city water inlet, but that is a topic for a different thread! Many thanks for all of the replys, leads, and suggestions.

[tpi]

"replace igniter wire and probe"

If it is what I think you mean, the official Dometic name for this is the "electrode." A thin wire leading to a spark plug like device which also senses the flame.

I'm on my third one, the original and two replacments FWIW. They seem to last me about two years or so. They seem to fail when its cool and damp outside.

[Scott J-24]

Originally Posted by tpi

"replace igniter wire and probe"

If it is what I think you mean, the official Dometic name for this is the "electrode." A thin wire leading to a spark plug like device which also senses the flame.

I'm on my third one, the original and two replacments FWIW. They seem to last me about two years or so. They seem to fail when its cool and damp outside.

Yes, it was the electrode. Guess I should pick up and extra and keep it in my spare parts kit.

[jm2]

and if you don't have a spare electrode (or flame sensor?), try a little fine abrasive like an emery cloth, or wet or dry paper, or a fine file to "clean" the portion of the electrode that would be in the flame back to fresh metal.

this will often work for you.

ymmv.

best,

[Scott J-24]

Originally Posted by jm2

and if you don't have a spare electrode (or flame sensor?), try a little fine abrasive like an emery cloth, or wet or dry paper, or a fine file to "clean" the portion of the electrode that would be in the flame back to fresh metal.

this will often work for you.

ymmv.

best,

Turns out that the wire attached to the electrode had a break in it (inside the insolation). I probably should have checked for continuity earlier than I did.

[AirHeadsRus]

Another twist to this problem. My Dometic 2803 will light and stay lit for about 3 mins. Then it shuts down. The whole time the spark is going like it is trying to light the gas, which is burning strong. I assume it is the Thermocoupler. Great flame so I do not think a problem there.
Any thoughts, just got back from an 18 day trip and looked at it this afternoon.
Regards,
Joe

[richie rich]

Never did have a problem keeping that ice chest lit,did ya?

[B&J]

A spider could have gotten in the line and spun its web. We experienced the same thing with our frig at the beginning of the summer. Ours 2005 28ft CCD hadn't been used for almost 2 years. We took it to Canada and drove 3600 miles. We were gone for 3 weeks and it worked perfect. It is still functioning with no problems. Hopefully you will have the same experience with yours, but I understand the worry.

B&J

[SeeMore]

@AirHeadsRus - Thermocoupler is most likely your issue as the igniter is not getting the message that the flame is lit and shuts down the solenoid.

[jm2]

a gas appliance (furnace, water heater, refrigerator, oven) with a standing pilot commonly uses a thermocouple.

a gas appliance (furnace, water heater, refrigerator, oven) with an electronic ignition commonly uses a flame sensor.

they do essentially the same thing for the appliance, sense when the burner is properly lit, and keep the gas valve open until whatever thermostatic device or temperature limit says it's hot enough for now....

your "newer" appliances will tend to have electronic ignition.

the ideas discussed here apply to more than just furnaces - Thermocouple & Flame Sensor Troubleshooting - Step by step w/ VIDEOS

best,

[Scott J-24]

Originally Posted by Scott J-24

After cleaning and blowing out the gas orifice, the refrigerator still would not light. The next step was to replace the igniter wire and probe. That did the trick, now it fires up in the first ignition cycle. One problem down and now on to the next... an intermittent leak at the city water inlet, but that is a topic for a different thread! Many thanks for all of the replys, leads, and suggestions.

Well.... Looks like there may be more to our problem than a bad electrode. We were getting ready for a weekend trip and the fridge still won't start on gas. I ran the ignition cycle 8 or 9 times and it just wouldn't ignite. I know there is propane in the tanks because I ran the gas burners to bleed the gas lines prior to starting the fridge. Taking it to the local dealer instead of camping this weekend. We will be leaving on a two week trip up to Washington State and back at the end of August and don't want to have problems with it while on the road. Hope this does the trick.