Dometic 2852 Frige not operating while mobile -SOLVED READ BELOW

[etu]

We have a  2016 Keystone Cougar 5v we really enjoy. Only problem is our frig will not work on propane while traveling. Works fine when parked on eithe gas or electric.

I've researched the problem and read a number of cases where wind causes the flame to go out. Some folks have made shields from sheet metal, some installed upgrade shields from the manufacturer. Best I can tell ours has the upgraded shields already in place.  I even installed a 1"x10"x20" ac filter inside the cover on our last trip but that was no help. 

The igniter works fine, the flame looks good. There is no air ratio adjustment on the burner and the setting of the thermo resister tip in the flame is according to spec.

What is the next logical step? I was thinking of checking the connection of the thermo resister inside the circuit board control  box but not sure what to look for? We are headed out again next Tuesday. Any advice will be appreciated. Thanks

Edited November 21, 2020 by etu

[Kirk W]

The first thing I suggest is that you download a copy of the Dometic 2852 service manual to use in troubleshooting. Next is a question, do you get any sort of error lights when this happens and if so, what are they? 

Since your refrigerator works when you are not traveling it sees a safe bet that this is caused by travel so it would not be a bad thing to check all electrical connections to make sure that they are clean and tight. If not that, then wind is the most probable cause. I would be very cautious about putting filter material into the path, as it could create problems with proper ventilation but I would fashion some sort of wind protection for the burner that allows free air flow through the bottom to top but no direst wind. Has this always happened, or is in something that just started?

There is probably no reason that you couldn't travel with the refrigerator turned off as many people do and it will stay cold for hours if the door is not opened. 

[etu]

Thanks Kirk. I had read that service manual but it is for a RM not DM and I've not found a service manual specific for a DM2852 which what we have.  On the model we have, there is no thermocouple, instead it has an integrated igniter. 

Yes it gives the "check" light code.  We just bought the camper from the original owner in March. They only used it twice. The problem has occurred on all 5 of our outings since we've had it. 

Agreed, even in the check mode it stays cold between home and our campsites which hare mainly 3-6 hours away. Still my older camper with similar fringe always worked on propane while mobile. I'd still like to get it sorted out. 

Im thinking (that's scary...) there could be three possible reasons:

1) wind- but I've verified we have the factory wind shield upgrades 

2) integrated igniter or loose connection at circuit board

3) bad circuit board

I don't think it likely to be bad circuit board cause it works on electrical or gas when parked. I'm going to check the connection of the igniter and circuit board. 

Eddy

[D&J]

First everything works unless you are moving so that eliminates all the obvious things. Remove the lower burner covers so you can see it and make sure it's clean, along with the flame sensor and the air inlet for the burner. Unlike when you are sitting still everything has to be in really good condition or it won’t light when moving, also make sure all the burner shields are in place so the only air comes in the bottom of the burner not the side. After that check the LP regulator, same thing it has to right or it won't light when moving. 

Denny

 

[etu]

Thanks for the input D&J. Yes I've removed all the shields and checked& cleaned the burner and confirmed spec on the ignighter spacing. Everything looks fine. 

Today I removed cover on circuit board and checked the connection of the igniter. Also checked that ground wires were tight and the connections going to the gas valve were clean and tight. We'll try it again on Tuesday when we hit the road again. 

[Tom_M]

Thankfully my fridge works fine while mobile. One option is you could get an inverter and run the fridge on AC while mobile. I believe the the heating element draws about 300 watts so get at least a 500 watt inverter.

[Wrknrvr]

    Do your 12vdc lights work when disconnected from shore power. If not then the battery disconnect is turned off . Hence now 12vdc power to operate the fridge.   

 

 

 

  Vern in a 

[Kirk W]

11 hours ago, etu said:

We'll try it again on Tuesday when we hit the road again. 

We will wait for your next report. Mean time thinking about possible causes.

[etu]

Thanks for everyone's feedback. I'm really beginning to think it's a loose connection or poor ground. The service manual does say a loose ground will produce erratic behavior in gas mode. That might explain why it works fine sitting but goes out on the road. Yesterday with access panel off I tried to blow out the flame and could not affect it at all. However If there was a bad or intermittent ground, it would shut off the solenoid and set off a series of reignition attempts. 

 

[Ray,IN]

Dometic DM2852 service manual.

I suspect you are correct thinking it is a poor/loose ground. Over 80% of all 12V issues are the result of a poor/missing ground. Finding that defective ground is the work.

 

[Kirk W]

2 hours ago, etu said:

However If there was a bad or intermittent ground, it would shut off the solenoid and set off a series of reignition attempts. 

Any loose connection could do that so pay close attention to the gas supply valve connections. I would also take a close look at the 12V power connections as that could also cause the problem. It is popularly said that 80% of the 12V problems are related to grounds and while I do agree that it is a common problem in automotive electrical systems, my experience as a career tech do not agree with that for most appliances. Since it happens when traveling, look really hard at all connections and especially those where plugs attach to a circuit board. I would also suggest the use of some contact cleaner and one of those cans of compressed air. Be careful in using an air compressor as the air may not be dry and you don't want to introduce moisture into the connections.

[Ray,IN]

To use a VOM to check status of a ground, attach one lead to battery negative cable, other probe to appliance ground wire, if the reading is less than .05 ohms the ground is good. If the reading is higher begin checking "legs" of the ground path.

[etu]

Thanks Ray. I'll check this out after our trip this week.

[Kirk W]

The return side of most 12V systems is chassis ground. Some years ago there was a rash of refrigerator problems that was related to problems in the chassis ground. While I do not remember what make or model of refrigerator that was, the solution recommended at the time was to run a wire from the negative side of the RV battery all of the way to the negative connection of the refrigerator power connections. I believe that was at least 10 - 15 years ago now.

You can check the ground with an ohm meter by reading from the battery negative to the chassis and then from the refrigerator return to the chassis. If the total resistance of the two is less than 1 ohm it is pretty safe to consider it good, but since we are dealing with an intermittant problem here, even a reading of 0 ohms does not eliminate this as a possibility. The best thing would be to make certain that every electric connection is clean and tight. 

[etu]

my camper has that extra ground but when I get back home I'll check all those recomedations. Just an update it still did not work while traveling to our campsite today. Also I believe it failed on gas as soon as I pulled the shore ac power. I could not get it to re ignite at home this morning before pulling out.

When we arrived at campsite I checked it after we got settled in and it ignited on the first click  but we were connected to AC power. Tomorrow I'll switch to gas and turn off Shore power to confirm if happens again.

 

[D&J]

5 hours ago, etu said:

my camper has that extra ground but when I get back home I'll check all those recomedations. Just an update it still did not work while traveling to our campsite today. Also I believe it failed on gas as soon as I pulled the shore ac power. I could not get it to re ignite at home this morning before pulling out.

When we arrived at campsite I checked it after we got settled in and it ignited on the first click  but we were connected to AC power. Tomorrow I'll switch to gas and turn off Shore power to confirm if happens again.

 

Sounds to me like you have a bad battery, when you pull the shore power check the battery voltage.

Denny

[etu]

Thanks to all for your input. The problem is the flex gas line was being crimped when the slide was closed. I removed the zip ties so the line could flex and it works fine now.  I'll try to attach a photo.

 

[etu]

[Kirk W]

15 hours ago, etu said:

The problem is the flex gas line was being crimped when the slide was closed.

I had not thought of the refrigerator being located in a slide, but that would clearly cause the problem. I suspect it would have happened sitting still if you had closed the slide. I had not run across that isse but have seen several different plumbing problems with kitchen slides that have the sink in them. 

[D&J]

16 hours ago, etu said:

By looking at that it looks like you could loosen the fitting and turn it so it would stop the crimping all together. 

Denny 

[etu]

You're right on Denny I did that and it helped but the repeated crimping every time the slide was returned looked like it had compromised the pipe so I have a new one coming. 

4 hours ago, Kirk W said:

I had not thought of the refrigerator being located in a slide, but that would clearly cause the problem. I suspect it would have happened sitting still if you had closed the slide. I had not run across that isse but have seen several different plumbing problems with kitchen slides that have the sink in them. 

Kirk when I found this it was after I'd tried to ignite the gas with the slide in after returning home and before hooking to shore power (still thinking about electrical issues). I could hear the igniter working and realized the problem was no gas. I slid underneath to look at the gas supply lines and there it was.

Every time before when I'd tried to run it on gas it would be when we were packing up to leave for a trip and the slide was out. The last thing I'd do after converting to gas (always successfully) is close the kitchen slide. After the slide was in I closed and locked the doors and the trip began. I would only realize the check light was on down the road at rest or fuel stops. 

Its so obvious in hind sight!! 

Thanks again for all the input. 

Eddy

[Kirk W]

5 hours ago, etu said:

Its so obvious in hind sight!! 

One thing that my 40+ years of service work has taught me is that the solution to a service issue is always obvious, once we figure out what caused it!  ☺️

[Darryl&Rita]

7 hours ago, etu said:

Its so obvious in hind sight!!

That was some good troubleshooting. Often, the solution is only obvious after a lot of time, skinned knuckles, and pure chance. The winner is often the one who sticks with it long enough.

[noteven]

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