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Topic: Operational issues with the Dometic RMD8555 in a 2017 Unity (Read 2005 times) previous topic - next topic

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Operational issues with the Dometic RMD8555 in a 2017 Unity

We're having some weird issues with the fridge in our 2017 Unity and wondering if anyone else has experienced them.  We have not yet called the dealer (or Dometic).  Bear with me while I detail our observations.

For the first trip (basically 2 weeks), the fridge worked flawlessly.

For the second trip (another 2 weeks), the fridge worked flawlessly until the last 2 days.  We discovered after the first day of a 2-day drive (was operating on 12V during the drive) that it had warmed up inside to the low 50's in the fridge, 10-12 in the freezer.  No alarms; no faults.  Overnight plugged in (and control panel correctly displaying 120V power source) it did not seem to cool at all, either.

We put the coach in storage for a few days with the fridge off.  Pulling it out, turning the fridge back on (Automatic), it seemed to be cooling properly for the half hour drive on 12V and for the next day plugged in on 120V.  36 hours later, however, it had stopped cooling and started warming up again.  Manually selecting 12V or 120V the control panel would indicate the desired power source, but the outside piping remained at ambient temperature (we used an IR gun to measure), not warming up like it should.  Battery voltage was fine; 120V power was fine; 12V disconnect was on.

We checked the operation of the exterior fan thermistor switch with a heat gun - it did come on with heat.  We bypassed the thermistor anyway and let the fans run 100%, this did not change anything.

We switched the control panel to propane, the fridge cooled perfectly.

It continued to cool perfectly on propane for the next 2 weeks.  I switched it to Automatic and it sensed the 120V and ran fine for several days.  We then drove for a couple of hours and it switched to 12V and worked fine.  We arrived at a site, plugged in, and it sensed 120V and ran fine for about 36 hours then stopped cooling on electric again.  Rear piping cold, internal fins warming up.  We manually switched it to propane and it immediately started cooling and has been working fine.

It seems there is a control issue on electric (both 12V and 120V) that causes the electric heating element to turn off and not come back on.  The fridge is not giving us any errors regarding 12V or 120V heating elements.  It will initially cool on those modes, but it won't stay cooling in those modes beyond a day or so.  Again, both battery and shore voltages are good.

This isn't a situation where it can't keep up due to high ambient temperatures - when it worked well initially, it was in the high 90's/low 100's out.  Right now, it's in the low 70's during the day.  Plus, when it's refusing to cool on electric, we can touch the rear piping and it's not heating when on either electric source.

Any thoughts?

2017 Unity CB

Re: Operational issues with the Dometic RMD8555 in a 2017 Unity

Reply #1
That's crazy performance. That's why their called "Demonic" I would not risk spoiling anymore food until you call LTV and get RMA. Then find a good RV service center that won't make your RV a long term storage item and get it fixed or replaced under warranty.

Re: Operational issues with the Dometic RMD8555 in a 2017 Unity

Reply #2
Not to worry - I think the only thing we have had to throw out was a sandwich's worth of cold cuts.  We were/are not traveling with anything super perishable.  Plus if we leave it on LP, it works perfectly.  Since the initial cooling failure, we have only switched to electric/automatic when we were able to monitor the operation to catch it if and when it acted up.

We do plan to call our dealer and explain the problem (just picked up the coach in mid-July) and get it resolved.  I was just curious if anyone else had experienced the same behavior with one of these fridges.  I know there is a member on Sprinter Source who had all sorts of problems with his fridge, but his also stopped cooling on LP, which is not the case with us.

(We have a long RV history with 2-way fridges, so we do know to watch their temperatures closely.  Plus I'm the queen of food safety when it comes to temperatures ;-)  This is our first 3-way fridge).

2017 Unity CB

Re: Operational issues with the Dometic RMD8555 in a 2017 Unity

Reply #3
You can look at the forum posts over on the Sprinter Forum / Unity. They have Dometic refrigerator posts going almost continuously. That's how wide spread Dometic refrigerator problems go in the RV world. No forum discussion will fix your refrigerator that's still under warrantee. My best advice still... is take it in and get it fixed. You are more tolerant than me. That's an 11 week old problem on a new Unity you paid good money for. LTV will see that it's fixed to your satisfaction.
Personally, I leave my 2016 Unity refrigerator in the manual mode. While traveling it's strictly on propane. When we are parked with utilities, we switch to AC.  I never run mine in 12vt mode. It won't keep dry ice cold down here Texas. In manual mode you never need to worry about it changing modes and running the batteries down.

Re: Operational issues with the Dometic RMD8555 in a 2017 Unity

Reply #4
That's why their called "Demonic"
Never heard that one before LOL

Re: Operational issues with the Dometic RMD8555 in a 2017 Unity

Reply #5
My suggestion is to call Willie Neufield at the factory 877-992-9906 X236 and relate exactly what is in your post.  He may take a couple of days to get back to you but for me he has been invaluable resource.
Good luck.

Re: Operational issues with the Dometic RMD8555 in a 2017 Unity

Reply #6
Thank you for that resource!  We're wrapping up our long trip (visiting elderly parents) and will give Willie a call when we get home.  The fridge continues to have the same behavior, but since it works perfectly on LP we haven't had to interrupt our travels to deal with it.

2017 Unity CB

Re: Operational issues with the Dometic RMD8555 in a 2017 Unity

Reply #7
Panther,-- Is Willie Neufield a good "all round" resource, or just regarding fridge's? We are seasoned RV'ers but new to LTV. We just acquired a used 2017 TB and are in the process of geting aquainted with it. We come from a 2008 Air Stream travel trailer which was very "simple" compared to the "auto" equipment of the TB. So;---- I can see that we are going to have a lot of questions in the very near future. The more resources (for questions) the better!

Re: Operational issues with the Dometic RMD8555 in a 2017 Unity

Reply #8
We have had a similar but not identical problem with our Dometic Fridge in a 2018 LTV TB.  In our case and after several trips back to the dealer for repair the problem was eventually fixed by replacing the "Eyebrow" circuit board.  I assume that this is the circuit board directly behind the controls the sit beneath the freezer and above the refrigerator sections.  Prior to replacing the Eyebrow circuit board the following items were replaced:

                Main Circuit Board
                Main LP pressure Reducing Valve
                Complete refrigerator Wiring Harness

None of the above replacement parts fixed the problem and it was only after replacing the Eyebrow circuit board that our refrigerator started working properly which it has been doing for the past 4 months so we've got our fingers crossed!