Possible replacements for Dometic RML 8555 fridge

TampaSteve

2018/2019 Unity CB
Edit: my frost problem is only in the main compartment. The freezer has none.

I'm pretty sure it's not the ITC. Not certain, but if you remember performance in my garage was not like yours before I installed the ITC. US isotherm tech support told me it won't run well empty, which makes sense. It needs a mass of cold items to help maintain tempature when the door is opened.

I had to run the thermostat way higher than you to achieve the same result.

When I installed the ITC performance seemed the same.

But as you know nothing is ever really tested until you do a live run. This is only my third short trip since installed and each time I'm becoming a bit more dissatisfied with the performance, especially the gigantic frost iceberg. I had to defrost on the 4th day.

I'm certain no air is escaping where I drilled the hole it's full of silicone.

The door seals seem reasonably snug and somewhat present friction to a dollar bill.

The main door is quite right and takes a good pull to open.

Oddly my time to initially cool the fridge is not much different than yours a few hours.

So I'm a bit at a loss why the performance is so bad.



The only thing that was different about our Isotherm 219 installs is that I didn't add the temperature controller like you did. Installing that required drilling a hole into the refrigerator box to add the temperature controller sensor inside. Maybe there is warm air leaking in some how. I don't get any frost in my refrigerator area and only small amounts in the freezer but not for a couple of weeks into a trip. In fact I've never had to defrost once on a trip yet. It sounds like warm air is coming in either through the seal or the temperature sensor hole. You might want to check the door seal and make sure it's good. If you can't find any leaks then possibly adding some internal circulation fans would help. I hate to even suggest this, but removing the temperature controller maybe the best thing to do. I keep my setting at about 3.25 and my door temperature is 41°, but the interior temperature ranges from 32° on the back wall to 38° at the front of the shelf. In fact I still find some food items just starting to freeze when I go to use them. If anything sits on the back wall it will freeze solid, even more than on gallon of milk/juices. My compressor runs less than 4 times per hour, particularly at night. It may only run once an hour through the night. I guess a lesson s learned is try the stock Isotherm before you think about adding the digital temperature controller.
 
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SSTraveler

2014 LTV Unity Murphy Bed
Edit: my frost problem is only in the main compartment. The freezer has none.
I'm pretty sure it's not the ITC. Not certain, but if you remember performance in my garage was not like yours before I installed the ITC. US isotherm tech support told me it won't run well empty, which makes sense. It needs a mass of cold items to help maintain tempature when the door is opened.
I had to run the thermostat way higher than you to achieve the same result.
When I installed the ITC performance seemed the same.
But as you know nothing is ever really tested until you do a live run. This is only my third short trip since installed and each time I'm becoming a bit more dissatisfied with the performance, especially the gigantic frost iceberg. I had to defrost on the 4th day.
I'm certain no air is escaping where I drilled the hole it's full of silicone.
The door seals seem reasonably snug and somewhat present friction to a dollar bill.
The main door is quite right and takes a good pull to open.
Oddly my time to initially cool the fridge is not much different than yours a few hours.
So I'm a bit at a loss why the performance is so bad.
I agree with you it doesn't make sense. We are using them in the same 100° outside temperatures. My Refrigerator compartment actually acts like a frost free Refrigerator. I can see water droplets frozen on the back wall at times and the wall reads 21°, and then at other times the water droplets are liquid and running down the back wall and dripping out the drain line (my drain line comes out the bottom vent cover and is pushed through a vent slat). It cycles like this so no frost/frozen water ever builds up. When I called Isotherm early on, I asked them about the "frost free" reference from the installation manual. I wanted to understand what to expect as far as frost buildup because I fought it with my Dometic. My Isotherm is performing just as they described. I would call Isotherm and discuss it, something is not right!
 
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TampaSteve

2018/2019 Unity CB
I agree with you it doesn't make sense. We are using them in the same 100° outside temperatures. My Refrigerator compartment actually acts like a frost free Refrigerator. I can see water droplets frozen on the back wall at times and the wall reads 21° and then at other times the water droplets are liquid and running down the back wall and dripping out the drain. Maybe your drain line is letting warm air in, I'm grasping. I would call Isotherm and discuss it.
Funny you mention the drain line. I always wondered how much of a heat loss that is. However mine is the same as yours, just much longer, so I am not seeing how that could be it.

However I think the situation just resolved. We are in a driveway in Maryland, and on the 4 days here it performed kinda ok except for the excessive power consumption and frost.

As soon as we parked here it seemed to get worse so we transferred the food to the house fridge and did a quick defrost with a fan.

It's dead now. Compressor runs but 3 hours later it only cooled freezer 5 degrees, so it's a goner.
 

Pine66

New member
I'm writing about the fridge in our 2012 MB. The RV took a lightning hit last winter, and we still don't have the fridge working right. The insurance company just asked me to get a replacement estimate. I assume that they'll pay to have the RML 8555 replaced, or pay that amount towards replacement with another fridge.

So - does anybody know if that particular model has done well or badly, or does anybody have suggestions for an alternate fridge/freezer with the same footprint? We only made one 2-week trip with the RV before we got hit, so I don't have much to go on, but the fridge didn't seem like a solid performer - we never could get it down below 40-42, and it was sometimes hard to keep it that low.

I'm curious whether anybody has enough travel on a rig with the new 2-door Dometic fridge to know whether it's a good performer.

Any comments or suggestions would be interesting. Thanks - Peter
Peter, I have a 2018 LTV Unity MB and had cooling problems with the fridge. Tried all the tricks, but it failed on a trip in 2019. We were traveling near the LTV factory and arranged for a replacement RMD8555 fridge to be installed under warranty. This summer, 2020, the new fridge would not stay cold, so i'm planning to install an Isotherm Cruise 165 12v/120vac, compressor fridge this winter. The dimensions show that it is an exact fit, slightly shorter than the Dometic. I will be doing the install myself and will document the process. Would be interested to hear your latest plans.
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
We replaced our RML 8555 with an identical unit - at the time I couldnʻt get an RMD8555 in Vermont. The replacement unit also had difficulties cooling, very similar to the original unit. I pulled the fridge, insulated the compartment with rigid foam, and put fans in the space behind the fridge. This made it better than it was, but still not really good. But the experiments were cut short - we traded the MB for a new 2020 RL. We havenʻt traveled a lot with it yet, maybe 5000 miles, but so far the newer model fridge is working much better. I find I have to adjust it a lot between 3 and 5 bars, as it sometimes gets very cold and other times starts warming up. But thatʻs fine - the old fridges rarely got cold enough and often went up over 50 degrees.

We have 400w of solar on the RL, and Iʻll watch how it behaves and think about whether weʻd want to go to a compressor fridge, but we donʻt have anywhere near enough experience with the new rig yet to know anything solid.
 

TJLee089

2013 Itasca Reyo 25R
It appears that the 2020RL has a Dometic RMD 10 series fridge. I'm wondering how the specs and performance compare to the RML8555. The only difference I see in the specs is 250w input on AC vs 190w for RML8555. 170w on DC for both. Not sure about gas. If the RMD 10 has a better way of rejecting heat to the outside, that would sure help. In moderate temps (<75F or so), my RML8555 works fine. Above that, things get iffy.
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
I havenʻt been on the road enough to really know much about the RMD 10 yet. I have noticed that when Iʻm parked at home and plugged in, it gets quite cold - Iʻve backed off from 5 bars to 4, and even 3 to make sure the fridge section doesnʻt go below freezing. As soon as I get on the road it wants to be on 4 or 5 or it heats up over 40. But this could be caused by many things - I really have to use it more before I know.
 

TJLee089

2013 Itasca Reyo 25R
I've never been sure that the setting on a Dometic 3-way corresponds to a specific temperature setting like in a conventional compressor fridge. As you indicate, a setting of 3 can be sufficiently cold or too warm depending on other conditions. Perhaps the setting (1-5) corresponds to given heat input to the boiler, which could be too little or too much depending on external conditions. In any case I almost always run mine at max cooling. The fridge never goes below about 33-34F and I never get frost in the fridge. I'll likely never replace mine but am still interested in the experience of others.

I havenʻt been on the road enough to really know much about the RMD 10 yet. I have noticed that when Iʻm parked at home and plugged in, it gets quite cold - Iʻve backed off from 5 bars to 4, and even 3 to make sure the fridge section doesnʻt go below freezing. As soon as I get on the road it wants to be on 4 or 5 or it heats up over 40. But this could be caused by many things - I really have to use it more before I know.
 

TJLee089

2013 Itasca Reyo 25R
Do you mean 600 watts? Watts per day has no meaning. Watts is power, the rate at which energy is produced/consumed. A 100 watt lightbulb on all day uses 2400 watt-hours (2.4kwh) of energy. This is how electricity is billed.

600 watts per day seems kind of high,
 

SSTraveler

2014 LTV Unity Murphy Bed
600 watts per day seems kind of high, I don't think the Vitrifigo on my boat used near that. Is that amp draw that other people are experiencing with a compressor fridge?
Watts=Amps x Volts (12vdc), so 600w/day translates to 50amps per day or about 2ah (amp/hour) power consumption rate. This is about what I see for power use on my Isotherm Cruise 219 as well. The Isotherm Cruise 165 (165L/5.83cuft) and 219 (219L/7.73cuft) use the same sized displacement compressors, so no matter the actual dimensional size of the refrigerator they generally use the same power.
 
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Peter Tourin

2020 Unity RL, ex 2012 Unity MB
The 600 watts/24 hours comes from the specs on their website. Look at SSTravelerʻs calc of 2 Ah average consumption and that fridge sounds pretty good. My RML8555 drew 17 amps - thatʻs a big draw on a hot day when the fridge is running most of the time. That makes that Isotherm sound pretty nice if you have a reasonable amount of solar on the roof...
 

TampaSteve

2018/2019 Unity CB
My Isotherm Cruise 219 unfortunately uses a LOT more energy than the advertised amount. I average a bit under 6 amps when running. At 13 volts thats something like 78 watts, still quite a small number. But in a day mine easily runs 20 hours if not more, so its something like 1.5 kWh in a day or more than 2 times what SSTraveler reports. So far I haven't been able to identify the discrepancy; maybe I just got a lemon. But my initial time to cool is a respectable 3 hours or so which would appear to demonstrate nothing is wrong with the compressor. So far I have replaced the Secop controller, got a new door under warranty, and installed a latch to pull it firmly closed. My next little trip is in a couple weeks and then I'll see if it made any difference.
 
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TJLee089

2013 Itasca Reyo 25R
Your use of units is confusing. I believe you mean "600 watt-hours/day translates to about 50 amp-hours per day (600/12) or about 2 amps (~50/24) power consumption rate." Watts/day and amps per day have no meaning in this context. It's like saying miles per hour/day.

Watts=Amps x Volts (12vdc), so 600w/day translates to 50amps per day or about 2ah (amp/hour) power consumption rate.
 

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