Ready for a new refrigerator

[HeadedToTexas]

But not new headaches. If Helmsman is building new models with Nova Kool and my experience with Norcold has not been good, what is the best upgrade path without having to rebuild the mounting cabinet?

The last straw was this weekend. Last week I found and replaced a blown DC fuse. The cheap fuse holder looked charred at one lead, so I replaced it with a new and more robust holder. We arrived about 8:00 pm and the boat was at 54°. I powered up the AC fridge breaker and turned the thermostat to 4.5, but the green LED did not come on. I turned the thermostat back off, turned on the DC breaker, then set the thermostat to 4.5 and the LED, compressor, and fan al came on.

About an hour later I looked over at the fridge and saw the green LED was off. The freezer was at 22° and the fridge was at 37°, so it had run for a while. Neither breaker nor the fuse was blown.

I turned both breakers and the thermostat off and back on. Twice the system clicked and the green LED came on for a second or less before going out. In end I just gave up on it.

If Norcold is rarely cold and Nova Kool is never cool, what is the right fridge for dependable operation yet minimal cabinetry work?

 

[AdmiralS]

That wiring looks like someone has been busy post factory installation.

We have been very happy with the RFU9200 in our 43. Ours is the single compressor version. Fridge stays at 38 degrees and the freezer around 24.

We would replace with the dual compressor version when the time comes so we can control fridge and freezer separately. We have a Dometic 100L freezer under the Saloon which stays at 5 degrees so that has worked for us to solve the freezer temp. We just keep some basics in the Nova Kool freezer and stock it from the Dometic below.

https://www.novakool.com/rfu9000-1

 

[O C Diver]

While this would be my recommendation, I can also appreciate not wanting to do surgery to your cabinet.

https://www.trawlerforum.com/forums/s31/my-new-apartment-refrigerator-41392.html

My other suggestion if you're electrically inclined, is as follows. The unit doesn't seem to have a problem getting and maintaining cold (as far as the compressor). If you're going to toss the unit when you replace it, why not just try making it a 12 VDC unit? Assuming it has a 12 volt compressor, why not see if you can eliminate the 120 VAC board and switching relay. After all, if it doesn't have a Frost Free cycle, the only electrical components that matter for the unit are the compressor, thermostat, refrigerator light circuit and internal or external cooling fans if there are any. Before starting a project like this, verify the unit is 12 VDC (compressor and fridge light bulb).

Ted

 

[DDW]

I replaced the Nova Kool in my AT with an Isotherm CR195. This was the only other freezer-on-the-bottom unit I could find. It has two compressors, required a small amount of trimming on the cabinetry to fit.

The good: it has been working well, the refrig has a built in circulation fan and does not seem to frost up, even long term. The freezer also works well, but does accumulate frost and must be defrosted every 4 months or so. It seems to use about the same power as the Nova Kool did. I like the separate controls for freezer and fridge.

The not so good: The latches are a little annoying to use. The shelves are made from thin gage wire, and flimsy, and their scheme for accommodating tall things (like a milk carton) is poorly done. I corrected this by making new shelves from thicker SS wire with a different layout. The door molding does not accommodate a 1/2 gallon milk carton on the low shelf (too narrow) nor a standard beer or soft drink bottle on the mid shelf (not tall enough). The former I fixed by modifying the fiddle holders, no solution to the latter. The interior design of several RV refrigerators I have owned (both Dometic and Norcold) have been better thought out.

I've been overall happy with the change, but it was not all positive.

 

[HeadedToTexas]

That wiring looks like someone has been busy post factory installation.

One of the POs definitely replaced the fuse holder, though the date is lost to history. It's been a while, though its failure now may well indicate some deeper problem with the Norcold control unit. After replacing the fuse, the control unit is next on their troubleshooting list.

...If you're going to toss the unit when you replace it, why not just try making it a 12 VDC unit?

It's definitely an AC/DC model with 12 volts on the DC side, and running it on DC would be an option. The shore power at our marina is quite reliable and when the time comes to spend longer stretches away from it, I plan to have solar on the roof.

The fuse failure concerns me though and I suspect a new controller is in the cards anyway, DC or not. That said, I might just be rationalizing the upgrade...

 

[HeadedToTexas]

...required a small amount of trimming on the cabinetry to fit.

As in making the opening larger, but not so much so that it required raising or moving either the top or the center (port side) wall of the enclosure? And still no problem with air flow across the condenser?

The door molding does not accommodate a 1/2 gallon milk carton on the low shelf (too narrow) nor a standard beer or soft drink bottle on the mid shelf (not tall enough). The former I fixed by modifying the fiddle holders, no solution to the latter.

That is disappointing. Figure that's a Euro container size problem? The Isotherm site makes it look like bottles fit, but they are't your typical US ½ gallon of milk or 2 liter of pop. Do US size 12 ounce cans of beer or pop fit on the mid shelf of the door?

 

[O C Diver]

It's definitely an AC/DC model with 12 volts on the DC side, and running it on DC would be an option. The shore power at our marina is quite reliable and when the time comes to spend longer stretches away from it, I plan to have solar on the roof.

The fuse failure concerns me though and I suspect a new controller is in the cards anyway, DC or not. That said, I might just be rationalizing the upgrade...

So if you run it DC only, why not just bypass the controller? Maybe I'm missing something, but shouldn't all the functionality of the unit be after the controller? If you can find the output of the controller, it should be pretty easy to try running it on 12 VDC.

Ted

 

[Comodave]

We replaced ours with an Isotherm CR271. We had to do some work on the cabinet but wow was it worth it. The new Isotherm works like a champ. We had it turned up around 8 out of 8 because every refer in a boat always had to be turned up all the way. It was freezing stuff in the refer. Eventually we had it turned down to 3 out of 8 and it doesn’t freeze in the refer but the freezer still freezes ice cream. We do have excellent ventilation around the refer and I added a 50 mAmp fan in the back blowing air up and out of the cabinet along with the builtin fan on the refer.

 

[HeadedToTexas]

I read Norcold called Nevercold and Nova Kool called Never Kool. What makes Isotherm so much better?

 

[HeadedToTexas]

Before calling Norcold tomorrow morning, I thought I should inspect the wiring to make sure nothing was loose or out of place. I pulled the fridge out to inspect the connections. All were secure and I found no loose or suspicious terminals. All wires are securely cable tied in place. Looked fine.

As a sanity check, I switched on the AC breaker and the fridge started right up. I switched off the AC and on th DC and the fridge started right up. I then turned on both AC and DC and the fridge did not start at all. Instead, it clicked and the green LED did not light. After both breakers had been off for five minutes, the fridge still did not start with either AC or DC on. It's as if some reset needed quite a while to reset. Yeesh.

Thinking back, it was this summer when I had cooling problems that I realized that this model auto-switched between AC and DC. The cooling problem was a fan not condensing refrigerant. The compressor ran just fine, but up to that point I ran it on either AC or DC switching it manually as the power status changed. It now seems likely that the relay that switches from AC to DC when the AC is out has not worked for some time. Hopefully Norcold can shed some light on that tomorrow.

 

[rslifkin]

For the modern units, Norcold, Nova Kool and Isotherm are mostly using the same mechanical bits. Differences are mostly in the insulation, compressor sizing, fan setup, and chassis design.

 

[Comodave]

I read Norcold called Nevercold and Nova Kool called Never Kool. What makes Isotherm so much better?

It works…

 

[Spinner]

Vitrifrigo has been great on my boat!

 

[Comodave]

Vitrifrigo has been great on my boat!

We had a Vitrifugo in our last boat and it worked great once we added high and low vents and a fan.

 

[catalinajack]

One of the POs definitely replaced the fuse holder, though the date is lost to history. It's been a while, though its failure now may well indicate some deeper problem with the Norcold control unit. After replacing the fuse, the control unit is next on their troubleshooting list.







It's definitely an AC/DC model with 12 volts on the DC side, and running it on DC would be an option. The shore power at our marina is quite reliable and when the time comes to spend longer stretches away from it, I plan to have solar on the roof.



The fuse failure concerns me though and I suspect a new controller is in the cards anyway, DC or not. That said, I might just be rationalizing the upgrade...

We replaced two household units with Vitrifrigo 12VDC-only units, no freezer sections. Even in very hot cabin temps they keep beer very cold. We have never had to turn the thermostats to max cold. I chose DC-only models cuz I never could see any sense, while away from shore power, to use DC inverted to AC only to be converted back to DC by a control module to run the compressor. Plus, those control modules do fail occasionslly and they are expensive to replace. You could, as advised by another, explore whether your fridge can be wired for DC-only and eliminate the AC middleman.

 

[catalinajack]

Before calling Norcold tomorrow morning, I thought I should inspect the wiring to make sure nothing was loose or out of place. I pulled the fridge out to inspect the connections. All were secure and I found no loose or suspicious terminals. All wires are securely cable tied in place. Looked fine.

As a sanity check, I switched on the AC breaker and the fridge started right up. I switched off the AC and on th DC and the fridge started right up. I then turned on both AC and DC and the fridge did not start at all. Instead, it clicked and the green LED did not light. After both breakers had been off for five minutes, the fridge still did not start with either AC or DC on. It's as if some reset needed quite a while to reset. Yeesh.

Thinking back, it was this summer when I had cooling problems that I realized that this model auto-switched between AC and DC. The cooling problem was a fan not condensing refrigerant. The compressor ran just fine, but up to that point I ran it on either AC or DC switching it manually as the power status changed. It now seems likely that the relay that switches from AC to DC when the AC is out has not worked for some time. Hopefully Norcold can shed some light on that tomorrow.

In another response, I mentioned that the control modules (not inexpensive) sometimes fail. It sounds very much like yours has. If the manufacturer recommends replacing it, I would opt for a DC-only model. By the way, like the Isotherm, our Virtifrigo fridges will freeze delicate items if we turn the theromstat down too low. As another responder mentioned, ventilation is VERY important. I custom-made an enclosure that draws air from underneath the base and out large top vents aided by 50 mAmp computer muffin fans driven by a tap on the control modules. Works like a champ.

 

[HeadedToTexas]

So "control module" in the context of marine refrigerators basically means "inverter?" I had been thinking that the Norcold control module did more than just that, like integrate the thermostat and low voltage shut off circuitry. Eliminating the control module sure makes sense if all it does is invert AC back to DC when it is available.

 

[rslifkin]

So "control module" in the context of marine refrigerators basically means "inverter?" I had been thinking that the Norcold control module did more than just that, like integrate the thermostat and low voltage shut off circuitry. Eliminating the control module sure makes sense if all it does is invert AC back to DC when it is available.

No, you can't just ditch the control module. It handles the thermostat, etc. And the Danfoss compressors don't run on DC, I'm almost positive they run on low voltage 3 phase AC (so the controller is doing power conversion regardless of input).

 

[lwarden]

We replaced an older Isotherm unit with the Vitrifrigo unit on our old boat and were very happy. The Vitrifrigo was very quiet and had a low power draw. The failure on the Isotherm unit was the 120/12V switching electronics, seems to be a weak area of that design. Our new boat has a 12V only fridge only which I prefer.

 

[HeadedToTexas]

No, you can't just ditch the control module. It handles the thermostat, etc. And the Danfoss compressors don't run on DC, I'm almost positive they run on low voltage 3 phase AC (so the controller is doing power conversion regardless of input).

That makes sense.

Our new boat has a 12V only fridge only which I prefer.

Our boat is 12 VDC as well. The Norcold will shut itself off when the voltage drops, but not until it drops to 10.8 volts. The damage is done at that point. How do you protect your batteries if you lose shore power while away from the boat?

 

[rslifkin]

That makes sense.



Our boat is 12 VDC as well. The Norcold will shut itself off when the voltage drops, but not until it drops to 10.8 volts. The damage is done at that point. How do you protect your batteries if you lose shore power while away from the boat?

The low voltage cutoff threshold is adjustable on the control module. I can't remember how to do it, but if you look up the Danfoss BD35 / BD50 compressor controller documentation it'll be in there.

 

[HeadedToTexas]

New intel from Norcold. Looks like the DE-0061 is not as smart as I gave it credit for. When the condenser fan died this summer, I dug into the manual (more than I had in the past) and read (or so I thought) that this model would run on either AC or DC. Here's the text from the manual.

DE /EV refrigerators operate on either AC and DC voltage or DC voltage only. If both AC and DC power sources are connected to the refrigerator, it operates on AC voltage. If AC power becomes unavailable, such as when you disconnect shoreline power, the refrigerator operates on DC power.​

Even after speaking with a Norcold rep just now, reading the paragraph above makes me believe that the DE-0061 automatically switches from AC to DC if the AC is lost. The Norcold rep assures me it does not. That jibes with the operation of my Norcold fridge prior to this summer when I ran it on either AC or DC, but never both.

 

[rslifkin]

New intel from Norcold. Looks like the DE-0061 is not as smart as I gave it credit for. When the condenser fan died this summer, I dug into the manual (more than I had in the past) and read (or so I thought) that this model would run on either AC or DC. Here's the text from the manual.

DE /EV refrigerators operate on either AC and DC voltage or DC voltage only. If both AC and DC power sources are connected to the refrigerator, it operates on AC voltage. If AC power becomes unavailable, such as when you disconnect shoreline power, the refrigerator operates on DC power.​

Even after speaking with a Norcold rep just now, reading the paragraph above makes me believe that the DE-0061 automatically switches from AC to DC if the AC is lost. The Norcold rep assures me it does not. That jibes with the operation of my Norcold fridge prior to this summer when I ran it on either AC or DC, but never both.

The quoted description is correct. For any of the units new enough to not have an external AC power converter (and just an AC input to the control module), the module will run on AC if it's available. When AC is lost, it'll shut off, wait about 1 minute, then start back up on DC. When AC comes back, it'll switch back to AC.

 

[koliver]

No, you can't just ditch the control module. It handles the thermostat, etc. And the Danfoss compressors don't run on DC, I'm almost positive they run on low voltage 3 phase AC (so the controller is doing power conversion regardless of input).

RSL:
That statement may apply to the particular Dan Foss in your fridge, but not to all Dan Foss units.

HTT:
My original fridge was a Norcold AC/DC that was a total power hog.
I went to a Refrigeration guy who knew enough that he had a widely known reputation, well deserved. You need to fine a guy like that in your town.
There was enough room in the base of the fridge for a total replacement of the guts of the Norcold, so out came the "controller" which was in fact inverter based. In went a DC only Dan Foss unit and my power hog was gone. So much so that I could reduce my house batteries to 1/2 their original numbers. DC consumption dropped to 1/3 of its former height.

I also kept the original Norcold body, so I had no woodwork to modify. Over the years I have improved that body, by substituting stainless sheeting on the face and by making aluminum framing where the old plastic stuff failed, so my fridge still looks relatively modern and still hasn't required any woodwork modifications.

 

[DDW]

As in making the opening larger, but not so much so that it required raising or moving either the top or the center (port side) wall of the enclosure? And still no problem with air flow across the condenser?



That is disappointing. Figure that's a Euro container size problem? The Isotherm site makes it look like bottles fit, but they are't your typical US ½ gallon of milk or 2 liter of pop. Do US size 12 ounce cans of beer or pop fit on the mid shelf of the door?

I had to widen the opening about 1/4", and increase the height by something like 1/2". The mounting flanges are also a little wider which requires a small notch out of the counter (which it is right against). The disappointment was that it is larger in O.A. dimension than the spec sheet says.

Yes, it is a Euro container size problem. 12 Oz cans of beer or pop would not fit in the mid shelf on the door until I modified it. There is a rail held by plastic bits which defines the width, I 3D printed an adapter to move it out about 1/4". Same thing on the lower shelf for milk cartons. The height problem (important for beer bottles) is unsolvable.

 

[rslifkin]

RSL:
That statement may apply to the particular Dan Foss in your fridge, but not to all Dan Foss units.

HTT:
My original fridge was a Norcold AC/DC that was a total power hog.
I went to a Refrigeration guy who knew enough that he had a widely known reputation, well deserved. You need to fine a guy like that in your town.
There was enough room in the base of the fridge for a total replacement of the guts of the Norcold, so out came the "controller" which was in fact inverter based. In went a DC only Dan Foss unit and my power hog was gone. So much so that I could reduce my house batteries to 1/2 their original numbers. DC consumption dropped to 1/3 of its former height.

I also kept the original Norcold body, so I had no woodwork to modify. Over the years I have improved that body, by substituting stainless sheeting on the face and by making aluminum framing where the old plastic stuff failed, so my fridge still looks relatively modern and still hasn't required any woodwork modifications.

Old Norcolds didn't use a Danfoss compressor, they used a Sawafuji unit that ran on 20 volts AC. Those were more power hungry regardless of power source. And some of the earlier Danfoss stuff had a DC only control module with an external AC power converter for the AC/DC versions. On any of the modern-ish Danfoss stuff (pretty much anything with a BD35 or BD50 compressor) the control modules all work similarly. An AC/DC unit running on just the DC input isn't any different power-wise than a DC-only control module.

 

[HeadedToTexas]

Man, you guys are the best. I will do some investigation into the compressor type, but my Norcold is from 2006 when the boat was built. Is 16 years old in refrigerator year? More as I know it. Thank you.

 

[koliver]

Old Norcolds didn't use a Danfoss compressor, they used a Sawafuji unit that ran on 20 volts AC. Those were more power hungry regardless of power source. And some of the earlier Danfoss stuff had a DC only control module with an external AC power converter for the AC/DC versions. On any of the modern-ish Danfoss stuff (pretty much anything with a BD35 or BD50 compressor) the control modules all work similarly. An AC/DC unit running on just the DC input isn't any different power-wise than a DC-only control module.

Right
To be absolutely clear, the only thing Norcold about my fridge after improvement is the case. 100% of the old power hog was put in the trash. Now it is 100% Danfoss.
My post was for HTT to show that no woodwork is required if he can dump the original stuff and put in something better, without altering the fit in his galley.

 

[rslifkin]

As far as fit goes, my boat originally had an ancient Norcold. It was later replaced with a Vitrifrigo and then a Nova Kool. Both made units that fit the original hole without issues. The Nova Kool has the largest internal volume of the units that fit (which made a lot of the choice on the last purchase).

 

[Circumnavigator]

We had Vitrofrigo drawer units on Fintry (now sold) and were very happy until the gaskets failed after five years and the distributor could not supply new ones for the lower units. After fooling around with several of the distributor's attempts at getting it right, I put in foam gaskets from McMaster.com. That worked, but I have to wonder what might have happened if I needed something that I couldn't get from McMaster.


Jim