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Old 05-21-2012, 03:39 PM   #1
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Dometic, Norcold, or Atwood Reefer Choice

My 2003 Dometic RM2652 has been rebuilt from Dinosaur board to igniter to cooling unit over the years and is now headed for spare parts. Replacement is the best outcome given other issues such as cracked liner, gaskets, et al. I am evaluating all the major players.

I want to upgrade to a three-way if possible and am considering either the Norcold N641.3 6.3 cubic foot or the Atwood AT-0601LF as the replacement. Both match my cabinet opening (slightly smaller than the Dometic) and avoid that headache.

However, I have a few questions/reservations:

1-Is Atwood sufficiently large to survive economically so that parts can be reasonably expected to be available should Atwood drop the line for lack of sufficient sales? The base for Dometic and Norcold ensures after market parts and general availability, but I don't know anything about Atwood's refrigerator presence in RVs and their web site does not even list the refrigerator online.

2-If helium performs better in higher ambient temperatures (95+) with good cooling numbers achieved, does that also means it is less effective at lower temperature ranges: i.e., its better for summer-like southern latitudes versus colder, northern latitudes?

3-If I add 12v (3way) what size 12v power wire is required? I believe my Safari 28' S/O has a 14 gauge 12v connection for the current board & lights. I can't locate any amperage info for the Atwood nor Norcold but suspect it might be a 3-5 amp draw. Do I need 12 gauge? I prefer 12v over propane while driving to avoid fuel stop safety stops before proceeding into fuel stations.

4- Which units have the best meantime between failure among the three manufacturers? Should I consider just upgrading to the Dometic DM2652 and forgoing three-way?
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Old 05-21-2012, 04:03 PM   #2
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Just a comment, but the 12-volt refrigerator in our boat sucks one battery completely dead, overnight; and that unit is probably smaller than the size you are replacing. However, our boat is used primarily during the summer in 105-115 degree weather; so a battery might last a little longer in more moderate temperatures. Also, you would probably use two batteries simultaneously, which would help (in a boat, you have to save one battery so you can start the engine the next day). I would switch to propane if I could, but that fuel isn't safe in enclosed areas (i.e., below decks in a boat).

I suspect that if you intend to use 12 volts for extended periods (without shore power), you will need to add numerous solar panels and extra batteries, or get a generator.

I'm sure others will advise whether the 12 volts from your tow vehicle is sufficient to power the refrigerator while underway.
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Old 05-21-2012, 04:58 PM   #3
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Any 12 volt operation on an RV stile refrigerator is going to take 20 amps minimum (about 240 watts) for the 12 volt heater, not the 3 or 4 amps you have guessed. That is going to kill any battery very quickly, and is quite hard to get from the tow vehicle back to the trailer while traveling. You would need to upgrade the tow charge line significantly, and even then you may not be able to get that kind of power from the TV to the AS.

The line that is in your rig now, is only designed for the circuit board power, in the range of 1 to 2 amps. To deliver the 20 amps needed for a 12 volt option refrigerator, a #12 is minimum, and #10 is the least I would put in.

Overall, I do not recommend the 12 volt option in a trailer. In a motorhome, maybe, as you can tap directly into the alternator circuit with a shorter wire run.

There is always a debate on it, but millions of people have run millions of miles with their trailers on propane, with exceptionally few issues.

The facts are the current draw and the wire size, the opinion is the propane safety issue. LOL.
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Old 05-21-2012, 05:07 PM   #4
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Thanks for the input so far. I just finished removing the old unit and the wiring is 12 gauge.

I do NOT expect to use 12v for extended cooling as it is not designed to perform to that level. Its primary intent is the MAINTAIN an already cool/cold unit while driving between locations so you can avoid using propane on the road and its attendant hazard.

I believe all the manufacturers state in their literature that either 120 or propane must be used to chill a warm refrigerator and NOT 12v. The heating element is not as stout (less btu output) than the 110/120 element?

I agree with all who warn against straight battery bank draw down without either a sizable solar array or high output alternator charging the system.
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Old 05-21-2012, 05:13 PM   #5
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We're on our third Dometic, being full time, I don't consider it a bash against the manufacturer. Repairs to existing units are expensive (our first try lasted a year), so a fresh one with warranty is the way to go. We run propane on the road and are still alive. Our original was three-way and it prolly had a lot to do with the alternator going south.
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Old 05-21-2012, 05:22 PM   #6
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@idroba - just discovering reply to post time delay and auto spellchecker issues.

I meant 20 to 30 amp draw in my initial post. None of the product reps I have spoken to knew what the 12v system used in either amps or watts. I have a larger size alternator and 10 gauge wire to the rear of my truck bed already (extra 12v outlets and a 400 watt max 110 outlet). My concerns did include upsizing from the hitch back into the trailer.

I have driven a few thousand miles on propane with my trailer but I always stop short of a fuel station to turn it off before refilling. I drove a commercial rig for years and have seen too many accidental fuel dumps by drivers overfilling or bad cutoff handles.

P.S. I also have two group 27 AGM batteries.

Thanks
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Old 05-21-2012, 07:13 PM   #7
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Turning off the gas before fueling is very important, the main shut-off valve may need replacement after a while. Take the kids, pets and stand off.
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Old 05-22-2012, 03:19 PM   #8
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We have a Norcold in our trailer and it's great.

The 12 volt mode is for the road as was noted. It was basically useless in the B190 - I never noticed much improvement over having it on versus off, probably because the B190 - also being a truck - tended to get pretty warm on the road, and the fridge was above a rear tire. The 12 volt theory might work better in a trailer though.
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Old 05-22-2012, 04:59 PM   #9
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If you are seriously considering a 3-way RV fridge, why not a 12VDC/120VAC marine fridge? These are compressor driven, much more efficient than any RV-style fridge (especially when using a 12VDC heating element) by using a Danfoss compressor, and really get C-O-L-D! (No more RV soft-serve ice cream!!! )

Plus, they draw 3-4 amps on 12VDC and less than 1.5 amps on 120VAC.

If I were so reluctant to use LP, I would definitely investigate this as a viable alternative. I just replaced an RV fridge in a travel trailer with a Danfoss unit from Indel Webasto Marine. It is a well made, high quality unit, as are most of their competitors like Dometic, Norcold, Nova Cool and Vitrifrigo.

Take your pick........... Worth investigating
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Old 05-22-2012, 05:26 PM   #10
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Depending on the size of fridge you want…

Interstates come straight from Jackson Center with a NovaCool 12vDC/120vAC, but it's only 3.1 cubic feet, i.e. dorm-sized. Runs on 120v if there's any 120v source available— shore power, generator, inverter— but if you shut off the 120vAC, it switches automatically to 12v. Low current draw, as Lewster says. Way more efficient than a propane-fired ammonia-cycle refrigerator. I actually made ice in my ginger ale cans accidentally by leaving the thermostat set on 4 instead of 3 while driving to a campground.

I haven't looked into whether larger sizes are available, but I'm entirely happy with my NovaCool.
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Old 05-22-2012, 06:01 PM   #11
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Quote:
Originally Posted by Mike Leary View Post
Turning off the gas before fueling is very important, the main shut-off valve may need replacement after a while. Take the kids, pets and stand off.
Mike,

Do you have any information about this accident? I have yet to see a single case of a fire caused by ignition at a pump when the fridge is running. I have seen many motor homes that caught fire because of faulty gas lines but have yet to see one involving the dreaded fridge igniting at a gas station.
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Old 05-23-2012, 01:26 AM   #12
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Oops; amendment to my previous comment:

Lewster's post reminded me that the refrigerator in our boat is a marine refrigerator, which has a compressor. I hadn't even thought of it, but now I remember the noise from the compressor running at night.

An RV refrigerator might run longer than the one in our boat, because the compressor really sucks the amps.
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Old 05-23-2012, 06:09 AM   #13
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Quote:
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Depending on the size of fridge you want…

Interstates come straight from Jackson Center with a NovaCool 12vDC/120vAC, but it's only 3.1 cubic feet, i.e. dorm-sized.
Addendum: Mine is whisper-quiet. Can't hear it, whether it's running on 12v or 120v. Doesn't have to sit level in order to work, either, so it's ideal while you're driving to your destination.

Looked up the owner's manual. It's a NovaKool Model R31000AC/DC. Made in Canada. (Note corrected spelling of the name, 'kool' with a 'K')
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Old 05-23-2012, 06:22 AM   #14
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But what do you do when you're dry camping? 3-4 amps on DC seems like a fair-sized draw to me.

Our propane/120 volt fridge works extremely well. Last weekend, we dry camped in Shenandoah National Park with it on propane mode, and we'll certainly do that again. Plus our Airstream serves as a 'lifeboat' when the power is out at our house. My wife and I wouldn't want to give up that possibility.

By the way, it's generally okay to run an absorption fridge off level while you're on the road - the bouncing and moving around helps make sure that the coolant inside drains back to the bottom. The owners manual for the fridge in the B190 specifically said this.
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