Dometic fridge RM 8551 not igniting.

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Jun 24, 2019
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Hey guys, I am having problems with my Dometic fridge model # RM 8551. This is not the first time I have had problems with it. In Spring of 2019 I had the same issues. I posted on here and they basically said turn it on and if it gives a failure message turn off and try again. It worked and I was able to use it last year. This spring I attempted to start everything up and make sure it worked. The fridge had the same problem.  I would turn it on and hear a click but it wouldn't ignite. After cycling on and off maybe 50+ times it worked. I researched but couldn't find anything, and ultimately forgot about it. about 2 months later I tried starting it, tick, tick, tick and nothing. After messing around with it for an afternoon and doing nothing but cycling on and off it started. Yesterday I attempted to start it and again nothing. This time I didn't even hear a tick so I plugged it into shore power and appears to be working fine (other then it needs a new gasket on the door as it is missing). So my question is this, why am I having problems with the pilot light not lighting? and more recently why am i not get a "tick" sound. Just throwing it out there, the heater, hot water heater, oven, and burners ignite immediately. Also the fridge works on battery. Any tips would be greatly appreciated, diagram are a bonus being I am not mechanically savoy.

Thanks
Sam
 

Rene T

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I don?t have a answer for you it I?m just curious. Are you planning on running it without a door gasket and what happened to the old one?
 

regval

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Jun 4, 2015
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Lawrenceville, Georgia, USA
The ticking you hear is an electronically generated ignition spark, similar to the type used fire a spark plug but not at as high a voltage. The fact that the refrigerator will work on LP gas once the igniter lights the gas burner tells you that the refrigerator is capable of working.
The gas burner and igniter should be cleaned periodically, recommended interval is twice a year. A dirty igniter or burner will cause the symptoms you describe.

Here is a link to the service manual

http://bryantrv.com/docs2/docs/Service%20Manual,%20RM8xxx.pdf
 
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Update:

This information will better explain my situation of the missing gasket as well as the problems. So when the fridge has worked on propane in the past it got cooler then ambient temperature but never cold. I always thought there was another issue. When I plugged it into shore power the other day I was pleasantly surprised at how cool it was. I checked with thermometer and it was 63 degrees, the coolest it has ever been (I have never used the fridge as I have a Cabelas 100qt polar cap cooler). I just happened to feel cold air escaping. So I opened the door and realized that there was no gasket. I vaguely remember seeing something that resembled a fridge door gasket under the benches, I looked and sure enough it was the gasket. I put it on last night and this morning the fridge was under 32 degrees (the coldest it reads was 32 degrees, who knows how cold it really was) while hooked into shore power. I switched it to battery to see if it would maintain the temperature. This afternoon the fridge was 63 degrees while running on battery. I know battery doesn't work as well, but that seems way to warm... advice? Also today I removed the screw before the gas safety valve, gas came poring out. Next, I disconnected the line after the gas safety valve (no gassing coming out). I then removed the gas burner device/igniter/shield. I blew the gas line out with an air compressor and a small amount of stuff came flying out. I inspected the igniter and it looked in good condition. For extra measure I gently used a wire brush to clean any debris off. I then gently tapped on the flue and to my surprise no particles/debris came out (Is there a better way then taping on it?) I then reattached everything. I put it on gas mode and nothing. Not even the tick, tick, tick. I watched a couple videos and now I am wondering if there is something wrong with the burner control device? If so, that still doesn't explain why the fridge doesn't get cold while on battery... or does it?. Are they two different conditions? As always I appreciate your help and hopefully the new information helps narrow things down.

Sam
 

regval

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Lawrenceville, Georgia, USA
samthelionsman20 said:
Update:

I put it on gas mode and nothing. Not even the tick, tick, tick.
There are two heating elements in the chimney. One is for 120vac (shore power) and the other is for 12v. Based on your earlier comment, it appears the 120vac element is working but the 12v element is not working (bad) or the battery supply to the refrigerator is not sufficient to heat the element. This could also be the problem with the gas igniter, battery voltage too low for the burner control to work correctly.
Do you have any lights flashing on the display indicating a fault?
The service manual has instructions on how to turn on each function for testing. See page 58 "Service mode MES".
Use a volt meter to check your 12v at the Terminal Block. (Page 42)
Good luck
 
Joined
Jun 24, 2019
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When it is on gas mode after a couple minutes it flashes a red fault light as well as on the gas symbol. When on battery mode it does not give a fault, however it doesn't get cold enough. I ran through the test modes and on test mode 3, 12 volt heating element, I let it stay in this mode until it switched back to run mode (10 minutes). Being it switched over I am assuming it worked fine? I then checked #4 burner control device. I faintly smelled gas on the back of the fridge so, I moved to #5. Being I have no idea what this tests I tested if for maybe 3 minutes before moving to 6. When In mode 6 the lights turned on. Is now a good time to point out that this is the first time I have ever seen the fridge light turn on... more electrical problems? In regards to checking the terminal block, I have a multi meter, but again I'm not good when it comes to this stuff. In order to test this which mode do I put it on? Just looking at the diagram, I am assuming I am going to have to pull the fridge out to access this, correct? Also, the batteries were brand new in spring of 2019. Since purchasing them I have had a portable solar charger connected. The charger gives a voltage readout, currently it is 12.8volts with the fridge running on battery mode. My father-in-law is out of town otherwise he could help me, with that being said he can help when he is back. Do you have any other ideas other then testing the terminal block?

Also I just found this manual.  Based off of page 25, there is nothing wrong with the 12v heating element?

https://cdn.ltvdns.com/leisurevans.com/owners/3rdparty/Dometic-Refrigerator.pdf
 

Gary RV_Wizard

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At our Silver Springs FL home
Most of your LP gas mode problems sounds like air bubbles in the gas line.  Once you attempt enough times, the burner lights and seems to be ok.  That's not unusual if the gas supply has been shut off for awhile. Is that the case here?

The loss of the tick-tick-tick after cleaning sounds like (1)a poor igniter wire connection, (2) a broken igniter, or (3) badly placed igniter (the spark can't jump to ground.  However, the igniter technology in this model is a little different than the ones I'm experienced with, so I may be missing something.

The controller board only makes 3 tries to ignite (3 ticks) and repeats that cycle 3 times, with two minutes in between.


RM 8xxx series service manual:
http://bryantrv.com/docs2/docs/Service%20Manual,%20RM8xxx.pdf
 
Joined
Jun 24, 2019
Posts
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I replaced the burner control device and the fridge started immediately while on propane. Using shore power I got the fridge cold, switched it to battery and it remained cold, right up until my batteries died. Thank you for your help.

https://www.amazon.com/Dometic-2412789303-Refrigerator-Control-Igniter/dp/B01HQOFJDU/ref=asc_df_B01HQOFJDU/?tag=hyprod-20&linkCode=df0&hvadid=312111914138&hvpos=&hvnetw=g&hvrand=336693495040513329&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9029187&hvtargid=pla-493637547525&psc=1
 
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