Dometic fridge is driving me nuts

[Gorf]

Howdy all.  I've got a Domentic RM2652 in my BigFoot 29MH.  Recently it's started acting odd and I kinda can't figure out what's up even after reading through numerous posts on here.  I have two odd issues:

• When plugged into shore power, it won't actually RUN on shore power. It continues to try to ignite off of propane. Which leads to the second issue...
• I can hear it try to ignite off of propane.  I can smell the pre-ignition gas, I can hear the igniter go off, and I can just momentarily hear what I think is the sound of ignition for a moment. After three times, it clicks off all together and then the check light comes on.

Today, #2 occurred and from inside the coach I hear a pretty solid WOOF from outside. You know... that sickening sound of a cloud of propane igniting midair. Now I'm completely nervous about using the unit. Anyone offer any thoughts or opinions about what is going on?

[Heli_av8tor]

I would check the burner / flue for a critter obstruction.  (Anything from spiders and wasps, to little four legged ones.)

Tom

[donn]

Chimney, burner tube, and thermalcouple are all places to start.  If everything there looks OK, on Monday give the folks at Dinosaur boards a call. Its possible your looking at a board failure.

[QZ]

It may be better to call a mobile tech.

[Gary RV_Wizard]

It won't try to run on 120v unless it can sense 120v power on its power cord, which is simply plugged into a wall outlet behind the fridge.  You might have a tripped circuit breaker, or a loose/broken wire, or a faulty outlet.

Others have suggested reasons why the LP won't ignite & run, so you can start with their suggestions.  However, you can view or download the Dometic 2652 Service Tips at http://bryantrv.com/docs2/docs/1252service.pdf

[Boonieman]

I had problems with mine not recognizing when it had AC voltage too. If you take the cover off outside behing the refrig, you will see a little black box, maybe 3”x4”. There is a circuit board inside there that I replaced and solved that problem. I took pictures off the wires before I disconnect them so I made sure to get them back correctly. It has 12 volts DC and 120 volts AC in there, so be sure you kill the power if you are gonna do it yourself. I think it was about $70 and an hour of my time. After that, it still was doing some weird things so I replaced the control panel on the front of the refrig. Seems like it was about $70 also and took 10 minutes to replace, tops. It just pops out with a small screwdriver, unplug two electric plugs, plug in the new one and pop back in. All of this stuff depends on how comfortable with your troubleshooting skills or would prefer to let an RV tech do it. Some of those ignition issues can happen when your propane tank gets low, but Im sure you checked that. Good luck, just wanted to pass on what was successful for me, but may or may not apply in your situation.

[Alfa38User]

In that little black box mentioned above are 3 glass type fuses. The one labeled F7 (5a) is for the 120V heater. If that is blown, the fridge will  not recognize that 120V is available and will always start (or try to) on propane.

[Gorf]

Thanks everyone.  I really dug around in it last night and i'm pretty sure i've concluded that the controller board has gone bad on me.

One of the oddities is that I was probing different spots around the control board with my meter.  AC voltage before and after the fuse and at the spade connector.  And I couldn't figure out why the voltage was so low. I was only reading about 80v.  Then I realized it wasn't plugged into the ac source inside the fridge space there! I had unplugged it to move the cable. So I put my meter across the prongs of the AC plug from the control board and sure enough it's leaking about 80v ac.  I put my fingers across it and its not much of a buzz so I'm assuming it's a low current leak. 

I ordered a Dinosaur board online. Should be here in a couple days.  We'll see what happens.

[fred_allard]

I don't recommend replacing the control board as it will cost you a lot of money and not fix the problem as in my case.  Most rv stores will not give you a refund on the control board.  I suggest the following:   1).  unplug the refrigerator from the 120 volt trailer receptacle and plug into a long extension cord plugged into park service or home electrical service.  2).  while your trailer is plugged into 120 volt rv park service, check the 12 volts that is used to power the control board.  More than likely it will be ok. Then switch your multimeter over to AC mode and look at the very same terminals to see what kind of ripple AC voltage that is getting thru.  The Dometic manual will say that AC is ok... but don't believe them.  You should not measure any more than 1 volt of ac.  I chased this "driving me nuts" problem for a couple of years until I measured an ac voltage more than 1 volt.  To fix my problem I ordered a $30 filter, installed it my self in about 15 minutes and all my Dometic problems went away for good.  If you measure more than a volt ac then email me and I will give you more info about the filter and can take photos of where I installed the filter.  Good luck.   

[Boonieman]

I replaced my original Dometic controller board with the Dinosaur board based on many comments I had read on these forums. It seems substantially better made than the original Dometic, I hope that holds true. Anxious to hear if it fixed the problem. I’m envious of those that have the skillset too deeply troubleshoot circuit boards etc. Beyond basic troubleshooting on electronics (looking for blown fuses,etc) I end up being a parts swapper-outer. 😄

[AZgl1800]

the control boards are not all that expensive from http://www.dinosaurelectronics.com/Dom_boards.htm

and my Dometic won't run on 120 a/c either.
nothing wrong with the burner, it works fine,

the problem according to all the tech talks I have read go straight to the control board.

when I removed the cover, I can see why, my 2004 year model is covered with corrosion everywhere.  all the wires are white or green looking.... my Toy Hauler lived down in south Texas, and I'm quite sure the owner never once, did any maintenance on it at all.
Quite obvious when you get to looking around.

anyway, I am first going to remove the board, and give it a good bath with soapy water and a toothbrush.

let that air dry in the sun for a couple days, and clean every wire connector until it shines.
then if the controller don't work, will order up a new one.

[merlinrkd]

My 20 year old Dometic wouldn't run on gas. I just installed the Dinosaur board and it works now. I called the Dinosaur customer service for help with the board connections. They were outstanding.

[John From Detroit]

RV's contain many yards of ROMEX cable. this is a capacitive voltage divider so if you have an open or weak ground you can get a false voltage measurement.  Thankfully there is not a lot of CURRENT.  but it can still give you a rather good Tingle.

As to your opniion the board (control) is at fault.. I tend to agree.  The ignition failure sounds like what killed my furnace some years back (2011/2) by the way furnace worked fine last night thank Dinosaur boards.

As to the recommendation of Dino... Well as you may have guessed from the last paragraph that is what I used to replace my OEM Furnace board.. I observed the following:

1: Cost. Dino boards are anywhere from 1/2 to same price as OEM depending on the device.
2: QUALITY: no contest, Dino boards appear much more "Robust" way way more.
3a: I Have a theory as to what happened` to my OEM Board (What killed it)
3B: Dinosaur boards included a protective device that was not on the OEM board.. It appears they share my theory because that is what it is designed to replace

Conclusion: I highly recommend Dinosaur boards.