Dometic Refrigerator - Erratic on Gas

[Denver Transplant]

I've been having an interesting problem with my Dometic refrigerator in that it intermittently faults when attempting to light the burner while on gas. We have a Model DM2652 with the integrated ignitor/flame detector. We had it in to the dealer last year for a warranty fix - they said it just needed adjusting, but in fact, they didn't really fix it. I'm not excited about waiting 3-4 weeks for an appointment and then 3-4 weeks while they get to working on it.

Its not that the burner doesn't, light, but it appears that the flame isn't being reliably detected. You can hear the ignitor start sparking, and the burner lights. But the ignitor continues to spark for 10-15 seconds and then the controller turns off the gas, waits for its time out and makes another attempt. Sometimes you can hear a stutter in the flame and while the ignitor is sparking and sometimes not. Sometimes it gets it on the second or third try, but often it hits max tries and the fault light comes on.

A typical fix is turn off the refrigerator and turn it back on to allow it to attempt another burner light sequence (Usually during a 2AM trip to the bathroom) Usually its gets it then, but sometimes it takes a few more tries. I've never had it fail hard - we always get to eventually stay lit and the refrigerator cools as it should. Always works fine on 120 VAC.

Most common time that this occurs at night when its cooler and altitude might be a factor. This weekend we were at 8100 ft. For the first two days the burner lighting wasn't a problem, but for the last two days we had multiple faults including a few during the day when it was in the 80's.

Any thoughts or experiences?

[chuckster57]

We have had some luck removing the sparker/flame sensor and cleaning it with WD-40. Don't ask me how or why it works but I've seen it do the trick 3 out of 4 times.

[shov]

Added to the comment on the spark/flame arrestor....
I have in the past taken some fine grit sand paper to them and "cleaned" them up. But once you do that its just a matter of time before the will carb up again and should be looking at a replacement in the near future

[DenverCZBob]

Hey Denver Transplant,
Not sure if you will get any help from my thread last year but here is a link.
http://www.keystonerv.org/forums/showthread.php?t=23016

We will be soon taking ours out for the first time this year.
Hopefully she stays running!

-bob

[MissJordan]

Ours has the same problem, took it into the dealer like you to have it serviced and the mechanic told us that all these types of fridges will have problems running on gas mode when it's cold out and also at high elevations. Ours runs perfectly below 6500 ft but anytime we jump above that elevations it doesn't like to run right without messing around with it. Last weekend we were camped at 7600 ft and it was finicky but worked for extended periods of time


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[darrylwt]

I have had mine fixed a few times it just won't get down low enough, the temperature runs around 50 deg. and I replace the thermistor and that fixes the problem for a while and than its doesn't work makes no difference on LP or A/C not sure whats going on but I understand they have a new one the just replaces the end so you don't have to pull the unit out just to replace the thermistor.

[Denver Transplant]

Thanks for the input

I just got a new electrode today and will try replacing the existing one and while I'm at it will check the wiring connections. I've run across some other forums that suggest that a less than solid ground can cause these problems.

Next trip isn't going to be nearly as high so we may or may not see an improvement. I'd rather have the good old thermocouple instead of a system that tries and use spark voltage to detect a flame. I've run across too many engineers that think elegant is better than simple and reliable - they never worked on my projects again (and some got invited to find a more suitable assignment)

[DenverCZBob]

Hopefully you got your issue solved, but just in case, I updated my thread over in Repairs and Maint., Subject "DM2652". You can read the long version there or to sum it up. I replaced my stock board with one by Dinosaur and it ran great all weekend on the first trip after replacement.

-bob

[ESRAM]

DenverTransplant... Did you ever figure out your problem with the propane refrig at higher elevations? If so, what was your fix?

I will give you my observances or findings, since I also have the same problem... I have a Dometic DM2652 in a 2016 Cougar 24SABWE. The problem occurs at 7,000 feet and higher. It works fine at 4,500 feet. I am not sure what elevation causes the problem, other that the manual states 5,500 feet.

It appears when the propane will keep our refrigerator going (and not error out at 7,000 feet) the sound from the back of the refrigerator is that of a flame on a low heat. When it continuously errors out the flame sound is one that sounds like it is on high.

My second finding or input, is that I called Dometic a few weeks ago about this problem and they told me I need to lower my water column (W.C.) setting on my propane regulator. I have not done this yet - but I have invested in a WC gage and plane on doing some tests in the next couples of weeks and see if that works - my only hesitation on doing this is the sound I am getting from the back of the refrig when it works and doesn't work... Why am I getting a very different sound.

Anyway, if I find anything out I will post the results.

Thanks!

[denverpilot]

Couldn't changing the WC on the propane going to cause issues with the hot water heater and furnace?

(We haven't had any trouble with our Dometic fridge at high altitudes. We camped at State Forest State Park in May and the campground is about 8500 MSL as I recall.

[chuckster57]

There is a minimum amount you want at the regulator. What are you using to measure the pressure and where are you taking the reading?

[JRTJH]

I don't think changing regulator pressure is going to help. It "may" reduce the refrigerator symptoms at high altitude, but as said, what will it do to the furnace, water heater and stove/oven? Additionally, to "set the regulator" for operation at high altitude by reducing the WC pressure will "throw it off" at lower altitudes.

It sounds more like either an "air adjustment" (carbon buildup on the burner orifice) or a control board malfunction. I'd first follow the Dometic burner cleaning instructions (DON'T PUT ANYTHING IN THE RUBY DRILLED ORIFICE) and if that doesn't work, I'd look at replacing the control board. DINOSAUR ELECTRONICS builds a "very reliable" aftermarket board. I've used their products with great success in refrigerators, furnaces, water heaters. So far, I've replaced a number of "failed" OEM boards, but I've never had to replace a Dinosaur board.

[chuckster57]

X2 for Dinosaur boards.

[ESRAM]

Thanks for the quick replies everyone!

I did make one mistake on my model number it is a DM2852LBX. It is a 2-way refrig running on either 115vac or propane. My manufacturer number is 958530294 (is that the same as the product umber?)... I tried looking for a replace board here: http://www.dinosaurelectronics.com/Dom_Chart.htm but did not find the one matching the manufacturer/product number, unless I have the wrong product number... Anyway, if they make one I am definitely willing to go that route. (BTW, where is this board located?) OR am I looking for an igniter board?

The only thing that gets me is the sound it makes when the gas is trying to light. I can tell when it is going to light and when it is not. Also, the comment about the Dometic burner cleaning instructions (thank you!) Where can I find that and are they the same for all model numbers? Never mind, I found the cleaning instructions! Thanks!

Also, I noticed this morning that the flame on the stove changed a couple of time while on a lower heat, first is was all blue flames... That after an adjustment, it was about 50-50, blue and yellow... Just another observation....

Thanks again for all your inputs!

[tommy_z]

I've had some weird propane things going on lately after I failed to use my trailer for 4 months (:o). Fridge wouldn't light, stovetop was erratic.

I think I may have just had a bunch of air trapped in the line, which means air got in, which meant a leak. I found my tank connection was loose. I tightened it down, manually purged a bunch via my outside stove connection, and all was well again.

[JRTJH]

I've had some weird propane things going on lately after I failed to use my trailer for 4 months (:o). Fridge wouldn't light, stovetop was erratic.

I think I may have just had a bunch of air trapped in the line, which means air got in, which meant a leak. I found my tank connection was loose. I tightened it down, manually purged a bunch via my outside stove connection, and all was well again.

Additionally, spiders are "attracted" to the smell of propane and tend to build webs/nests in the burner box. If you've had your RV in storage for 4 or 5 months, you might want to doublecheck to make sure you don't have an air obstruction in the burner box as well as what you've already done.