Nova Kool? Dometic? Norcold?

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Aug 28, 2010
I need a marine 'fridge in my 31-foot Taiwan trawler:* the one that was there originally evidently died and the previous owner slid an AC unit into the space.* I am looking at several units.* My current favorite is the Nova Kook R4500, as that seems to have the largest volume, smallest freezer and lowest amperage draw;* my second choice is the Dometic CR-1110, which looks to fit well but has a larger freezer than I think I want and the highest amperage draw.* My third and fourth choices are the Norcold DE-0041 or DE-0788, which have too-large freezers but moderate amperage draw.

I would love to hear from folks who have one of these units and get their feedback.* I'd also like to hear from anyone who has recently gone through this same exercise (or is now going through it) and hear their opinions.* Thanks.
I agree with your choices. I replaced a Tundra (Dometic) with Nova Kool 3 years ago.
To add confusion to your search, you might also check out Isotherm. When our 14 year-old Norcold appeared to be dying a couple of years ago we researched the the heck out of what was available in a similar size and was AC/DC. Read reviews, talked to people on various boating forums, etc. In the end we selected an Isotherm unit. For whatever reason the Norcold decided to revive itself so we decided to let it keep going and not worry about a replacement until it truly died. But when that day comes, we'll go with the Isotherm unit we selected unless there's something we feel at the time is better.
Here's another option.* We put in a SeaFreeze custom unit*3+ years ago and like it.* They built the unit to our dimensions with added insulation.* There's separate compressor for the freezer*and refrigerator.* The refrigerator is about 6 cubic ft and the freezers about 2.5.* Not cheap though.


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We went with the Isotherm 12 volt after a lot of research several years ago. It cut our amp use by %40.

37' Sedan
We replaced the original refrigerators in our boat last fall with two Nova Kool 4500's. So far, they seem to perform as advertised.*

I think the original units were Norcold. They were about 2.5 cubic feet inside while the new units are 4.3 cu ft. even though the physical size is slightly smaller. It was an easy way to more than double the usable space.*

The original refrigerators were AC/DC, the Nova Kool's are DC only.

Before and after photos. The new units have black fronts.


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I had an Isotherm in my previous boat and have a Nova Kool in my Camano. Neither has had any problems.

I have read nothing but complaints about Norcold, but then, this is the Internet so that's to be expected.

If you spend a lot of time on the hook, efficiency is very important and that's what I would look for second to fitting in the boat.

It's hard to judge efficiency of a refrigerator becase, while*you can easily measure the current draw when the compressor is running, it doesn't run continuously.* A better insulated refrigerator will not have to run the compressor as often in a given time period as a poorly insulated refrigerator at a given ambient temperature.

-- Edited by rwidman on Friday 11th of February 2011 07:41:07 AM
Best refrigeration I ever had on a boat was a cold plate engine driven system by Sea Frost.*** Made ice fast- An hour operation kept the box cold for 24hrs.* They can have an electric backup for when you are not cruising.* The condenser is water cooled and it was reliable.**

On our IG we have the original 1983 Engel 2.5 under the counter. Works well AC and DC, I think the fact the builder provided a vent to the outside behind the unit helps it work so well.

Going to look into the isothems be nice to get a 4cu ft in the same space.

Amazing how long a refrigerator can last, but the PO had the boat on a mooring and maybe the unit was not used much.

In the front section of the latest PMM there is some good info supporting 12 V compressors used by Danfoss.
Actually I think Danfoss makes the compressors used by the more reliable brands of refrigerators. I don't think Danfoss is a user of compressors.* Isotherm refrigerators, for example, use Danfoss compressors.
Marin - To quote the statement from Danfoss on page 17 of the latest PMM - with my bold emphasis of the word used

"The polyphase induction -couples versions as usedon the current line of Danfoss ---"

My guess is they buy these from a supplier as they assemble their compressors. This is similar to what Boeing does on virtually every (well only the engines, electric panels, switch gear, wing spars, instruments, tires, brakes, headsets, carpet, seats, fuel tanks, pumps, hoses,*actuators, windows, glue, what did I miss?)*piece of the 787 which is yet to be deemed airworthy by the FAA.
Most all straight 12 or 24 volt manufactued boxes will utilize the Danfoss compressor & electrical module, except Norcold (we in the industry nickname Nevercold) which uses a 20 volt swing compressor that they step up or down power to with a propriortary power module that is expensive.

Typically the Danfoss boxes will have less cool down & run time than the Norcolds given the same size & insulated box.

The Danfoss units have fan forced cooling where the Norcolds never did (however I believe I read somewhere that they now do) and heat has always been the biggest killer of the Norcolds...

spcoolin wrote:

Most all straight 12 or 24 volt manufactued boxes will utilize the Danfoss compressor & electrical module...,
Steve:* Your right.* We have a Danfoss*BD35 compressor and a BD50.* The electronic modules are interchangeable and they will run on either 12 or 24 volts.* We bought a spare on on line for ~$200.00.* The new Danfoss compressors also have great diagnostics.*

We've got two Dometics with the Danfoss compressors. The one on the flybridge is mounted into the helm cowling and there for has tons of ventilation and works great. The one in the galley only works flawlessly in the summer when I turn on the 12v computer mushroom fan I added to the thru-wall vent behind the fridge.
sunchaser wrote:

"The polyphase induction -couples versions as usedon the current line of Danfoss ---"
Right, but that's not what you said.* You said "info supporting compressors used by Danfoss."* That's not the same thing as saying info supporting components used by Danfoss in their compressors.

It's just samantics I suppose, but perhaps you can see why your satement was easy to misinterpret.


There are oh so*many*little things to worry about when talking*samantics (oops to*your spell check) in* your satement ( your oops again).

On a more serious note, the 12 V motor used by*Danfoss is very efficient according to the PMM statements.

I enjoyed your piece about Kenmore in a magazine I saw at the Seattle boat show. It was well written, concise*and stayed on point.
Thanks for the kind words on the article but I'm a bit puzzled as I haven't written an article for a magazine in years. I think the last time I wrote a magazine article about anything was when I was asked to review the then-new Cub Crafter's Top Cub on floats for a national aviation magazine. Kenmore has one and I got checked out in it, flew it around a bunch in and out of the little lakes up in the Cascades, and got a factory tour from the president of Cub Crafters over in Yakima. But that was sometime in the early 2000s. I've since had a book about Kenmore Air published but no magazine article. Maybe somebody's writing stuff and using my name
That's okay as long as they split the fee.

One of the primary reasons we selected an Isotherm unit to replace our Norcold (when it decides to finally die) is the Danfoss compressor. Everything we read about them at the time indicated that was the way to go as far as a compressor was concerned. Glad to hear from your mention of the PMM article that they are still highly regarded.
IF you wish to check Pro Boat builder a couple of years ago they had a very comprehensive 2 part article on DC refrigeration.

The power controller and its method of selecting the compressor speed and time of operation are as important as the compressor to low daily amperage .

The article claimed the lowest amperage would be a 24 hour a day operation at slow speed , but the equipment aseembelers were worried owners would complain "it never shuts off".

SO 50 min an hour is used .
On our 3 year old Tundra/ Dometic T80 I just recharged it for the second time. Danfoss Compressor BD35F. Apparently I have a leak but after several hours yesterday with a sniffer and liquid leak detector I failed to find it. As with the last recharge, it cools/ freezes better than ever. The manual says "Do not attempt to charge unit in field". A pair of saddle taps, a non contact temp gun, amp meter, freon and free advice got me back to a working pressure. There is NO info online to tell you what pressure to recharge to. This is probably a temporary fix- but it's working great now.
When we replaced the same size Norcold, the two things I didn't care for were that the door latches are a bit cheesey- and you can't swap out panels in the front.
Forkliftt wrote:

.....There is NO info online to tell you what pressure to recharge to....
Interesting.* I checked on our BD35 and all is says is to charge 6.5 oz*with 134A.* No pressures mentioned.* If you find out please post.

When I "inherited" my MT34, a previous owner had installed an apartment-sized 120v Haier fridge.* Admiral loves having all that space, and since we are marina cruisers, it runs on shore power at home and at marina stops, and with a* dedicated 2000w inverter under way.* It's at least 9 years old, and shows no signs of rust or other deterioration from a marine environment.

We also carry a Honda 1000 genset for times when we do raft-ups, etc. and want to keep it cold.

You other MT34 owners will note that the port side of the salon was also modified to remove the upright cupboard and* settee, replacing with the fridge and a nav desk.

It's about 10 cu.ft. draws 11 amps. and probably cost $250-$300.* A look at Defender shows a 7 cu.ft. Norcold for $1280.* What am I missing?

-- Edited by ARoss on Sunday 13th of February 2011 09:30:16 AM


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I would put the bigger unit in today if I had room.

My sweet spot seems to be around 5 degrees low side, 138 high side. I am not an AC tech, but I feel it could stand a little more. After charging my freezer coils were running down to minus 5 DF, that seems sufficient.
Larry M wrote:No pressures mentioned.* If you find out please post.

That is because small hermetic systems are hypercritical as to the quantity of refrigerant in the system.

If you don't have a recovery system and a "dial-a-charge" and know exactly what you are doing - don't mess with it. You will create more problems than you will ever solve.

This is one of the few items on your boat where, unless you are trained, equipped, and certificated you should just leave it alone and call in a professional.
Thanks Rick for pointing that out. I should mention that several months ago that only after several other checks, including shooting temps on the compressor and coils, confirming no leaks on the door seals and pulling the unit from the boat cabinet to assure I had sufficiant air transfer did I make the decision to tap into the freon circuit to attempt to charge it.My thinking was that for $150 I didnt need a professional to tell me there was no way to charge it. At $1100, and it not working anyway, I didn't have much to loose. I added freon and the fridge worked a couple of months. And cooled better than it had new.

When I got the boat late friday PM I had gathered supplies and was ready to try this again. I used the sniffer in the upper and lower cabinets, showed no leak, then sniffed near the compressor and my recently installed saddle taps. No alarm.
I promptly hooked up my borrowed gauges and proceeded to accidently overcharge the ststem, I turned it on and the compressor came on line for about 2 seconds and stopped. The fan continued to run and 30 seconds later the compressor fired up again and stopped again same as before. A few more tries and the same result and I realized I had WAY too much freon (true).
I pulled the line from my freon tank and cracked both the Hi and Low valves and allowed the excessive pressure to escape (true). It soon became clear that my saloon was beginning to fog up with the bleed off. Interesting enough- I felt the ambient temperature around me start to rise and the water in the toilet in the front head rose about an inch (BS). Climate change maybe?
I'm not sure, but I opened the stbd door and put a fan near it to let it escape.
I was very tired by then, so I went on to bed. Woke up around 6:30 refreshed and the first thing I noticed drinking my Community Coffee was that I had charged the unit with R22 (should be 134a). I had the 22 there to freshen up my front AC unit (true). Dammit!
Needless to say, I put the fan by the stbd door again and proceeded to evacuate the entire system. I shot some 134 in and evacuated it again. Another shot, kicked the compressor on, then back off again and after evacuating it this time I charged to the correct pressure with 134a, where it is cooling great (true)! Ran it all night and all day today and everything appears to be fine. Say Rick, where can I get one of them there "dial-a-charges" at. Just in case (BS)?
He He He*
It's about 10 cu.ft. draws 11 amps. and probably cost $250-$300. A look at Defender shows a 7 cu.ft. Norcold for $1280. What am I missing?


For a Marina to Marina life style , you got it just right!!
Now I hope you have logged the discharge of all that frig gas with the EPA and you have a licence for doing so.
I don't know about the USof A but in Aus these days that is a criminal offense.

But s..t you gotta get the beer cold.

Forkliftt wrote:

...proceeded to evacuate the entire system. I shot some 134 in and evacuated it again.
How did you evacuate the system?**When we had a previous unit serviced, the technician used a vacuum pump to pull all the old gas, contaminates*and moisture out before recharging.

They make an AC evacuator pump.
On our recent cruise, I "fixed" the interior light in the Isotherm fridge which had never worked. A day or so later the admiral complained that everything was frozen although she had turned it down to "1".

My "repair"*had ensured that the interior light didn't turn off when the door was closed and, since the light is*right next*to the thermostat, the fridge just kept on cooling. I did wonder why the batteries were sinking a bit at anchor, when the solar panels normally keep them up.

So* now I can convert the fridge into a freezer simply by putting the light bulb back in!

I also discovered that the freezer (the real one) doesn't enjoy being defrosted with a ball-peen hammer. The temp probe is unduly sensitive!

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