Dometic RM8501

[tracenuttall]

Was thinking my Dometic RM8501 wasn't working, but have learned it can take up to 24 hours to cool.....? I find that amazing. Is this accurate. I have a friend with a portable Whynter 65 quart that will go from 95 to 35 in 30 minutes!!
I live in the desert in Tucson - I have had my Dometic on under covered parking for 12 hours now it is 42 degrees...... I thought I bought the best. Am I being unrealistic here or is this just a "bad" refrigerator?

thanks for any help/insight

new to Airstreams - this is my first and love it...... just not the refrigerator

Trace

[mayco]

Yyyyyyyup, the rv fridge takes quite a while to cool especially in warm climates, you can expect a good 24 hrs or so to reach temp. Different cooling system than a residential refer.

[idroba]

It is simply a characteristic of ALL propane fired refrigerators. They use a completely different cooling system than the usual domestic compressor refrigerator you are used to having. It has nothing to do with Airstream as such, Dometic and Norcold refrigerators are in the vast majority of RV's and they all use the same system of absorption cooling.

There are a few compressor refrigerators available in the RV sizes, usually using a Danfoss compressor on either 12 or 120 volts, but no propane. They can work very well, especially in hot weather, but unless the rig is on grid power or you have a very robust 12 volt electrical system including a lot of battery power, they run down the batteries quickly. You would not be happy with that either.

You do not have a bad refrigerator, they simply work differently from the ones you are used to.

[tracenuttall]

Thanks a lot for your response, really appreciate it. The fridge did get down to 40 degrees after 24 hours, then checked it again 5 hours after that and it had risen to 48 and the frozen nalgene bottle of water I put in there was beginning to thaw. It was 95 degrees here yesterday, but my Airstream is parked under a carport and is shaded nicely. I will keep working with it to see what I can get out of it. Thanks again, I feel better about understanding the Dometic's limitations. I will check it again later this morning when I get home and see where it's at.

Is it possible that it won't get to 37 because it is so damn hot here in Tucson?

[Mixter]

I have yet to use my fridge in a "real life" scenario.... I'm still deep in my renovation... But I do live and travel in the heat of the South, so I've been watching Fridge threads...

Do you have a fan or two behind the fridge to cool the heatsink?

i.e. There are 12v fans available to blow over the back of the fridge to help increase airflow over the back. They are like computer fans that you can get from Radio Shack. I believe they are on newer Aistreams, but are commonly added to older trailers.

Curious to know if this is an effective method to increase performance. I've read mixed opinions on it.

[idroba]

Originally Posted by tracenuttall

Is it possible that it won't get to 37 because it is so damn hot here in Tucson?

Yep, unfortunately the hotter it is outside the less effective the cooling in the refrigerator. They tend to limit out at about 100 f in my experience. Fans may or may not help much, it depends on the specific installation in your trailer. The newest smaller Airstreams have no chimney and draw air in and exit it out on the side wall and those models are factory equipped with a noisy and power hungry fan. I traded mine for a better, quieter one.

Your larger AS has a low air input and a rooftop heat outlet for the refrigerator, I believe, and has no factory fan. Some indicate that a fan can help even those units, I have no personal experience though, so will make no observations.

If you want to monitor the refrigerator temp, be sure to use an external reading thermometer, maybe one with a wireless connection. That will allow you to see what is going on inside without opening the door. Each door opening to check puts more load on the refrigerator, especially in hot weather. And don't get too paranoid about the numbers. You may not have instant ice cold beer from them, but usually the operation is at least acceptable in hot weather, and much better in cooler times. Live with it for a while and see what you think.

[Markj55]

Originally Posted by tracenuttall

Thanks a lot for your response, really appreciate it. The fridge did get down to 40 degrees after 24 hours, then checked it again 5 hours after that and it had risen to 48 and the frozen nalgene bottle of water I put in there was beginning to thaw. It was 95 degrees here yesterday, but my Airstream is parked under a carport and is shaded nicely. I will keep working with it to see what I can get out of it. Thanks again, I feel better about understanding the Dometic's limitations. I will check it again later this morning when I get home and see where it's at.



Is it possible that it won't get to 37 because it is so damn hot here in Tucson?

I've written this before about my Dometic and once again here goes. The Dometic in my 06 - 19' Bambi cools to below forty degrees in less than 4 hours on propane and about 12 to 15 on shore power which, I never use. Propane cools faster and tends to reach cooler temps....at least mine does. Try it and see if that works better. I was recently in heat in the high 90's and my ice and ice cream were rock solid!.... Good luck!


Mark,
"on the road again"

[Matthew014]

Let your frig cool down before loading it full of drinks. It has difficulty overcoming high ambient temps and trying to cool the items in it at the same time. Once it's cool, load it full of drinks and it will keep them cool without any trouble.


Sent from my iPad using Airstream Forums

[tracenuttall]

Originally Posted by Mixter

I have yet to use my fridge in a "real life" scenario.... I'm still deep in my renovation... But I do live and travel in the heat of the South, so I've been watching Fridge threads...

Do you have a fan or two behind the fridge to cool the heatsink?

i.e. There are 12v fans available to blow over the back of the fridge to help increase airflow over the back. They are like computer fans that you can get from Radio Shack. I believe they are on newer Aistreams, but are commonly added to older trailers.

Curious to know if this is an effective method to increase performance. I've read mixed opinions on it.

Hello,

Thanks for your input. I have a 2012 Sport and yes it does have the two little itty bitty fans that are on the "outside" of the fridge, accessed from the outside that is. Not sure if my fridge is worth the space it takes up.....
I have kept the fridge on for over 48 hours now. The lowest it got was 40 and then it went back up to 48 and then 55...... completely confused at this point by it's performance. Again, it is hot here but the trailer is parked in the shade and inside is not too bad. I have heard to put a small fan inside the fridge which I will do. I'm starting to believe the temp of the fridge is going to be relative to the ambient temperature in and around my Airstream. What a bummer.....

Trace

[TG Twinkie]

Trace;
Are you running the refer on propane? If not, try it. The electric heating elements have their limitations.
With ambient temps around 100. The refer will not cool like it would at 75 degrees.

[Matthew014]

You may also want to check and see what the frig temp is set at. Mine has 5 different setting, although I don't remember if 1 or 5 is the lowest setting. And I usually see the temp swing up and down maybe 5 to 8 degrees, but not much more that that.

[crispyboy]

Could there be an issue with the thermister?
I bought my trailer used and found out that the previous owner had taken out the baffle from behind the refrigerator. Over the winter I removed the refrigerator and reinstalled the refrigerator according to the specifications in the manual. This meant that I had to build a baffle behind the refrigerator where there was only 3/4" of space between the back of the refridgerator and the baffle. I also insulated the walls of the compartment and put insulation above the refrigerator to direct air out the roof vent. I put a 6" computer fan on the roof vent but I have only had to run it one time so far this summer.
The correct installation made all the difference in performance of the refrigerator. When I turn on the refrigerator it still takes overnight for the temps to stabalize on shore power but propane will bring it down quicker.

[Birdhunr]

When starting my Refrigerator, I put in a frozen 1 gallon jug and also some smaller frozen water bottles into both the freezer and Refrigerator sections. I also put in a cold water bottle or ice tray into the Freezer to monitor when it starts to freeze that water. This seems to greatly speed up when the Freezer reaches proper freezing temp. Also mine does cool better on Propane than Shore Electric and my 12 V Electric doesn't seem to work so no experience there. My exterior 12V Fan does help but mine is very very loud and probably needs replacing.