Two-Way Refrigerator?

[InterBlog]

Yet another update to this thread...

I can't believe this, but our "new" Dometic 2351 three-way fridge, which originally worked so fabulously, has gone tango uniform. It's just 20 months old and the parts warranty is for 24 months, but no labor would be included in a repair, of course. Which leaves us with the decision of whether to go all electric at this point, or start paying for yet another Dometic wild goose chase.

We did the goose chase with our original Dometic 2351, paying successively for the two most likely components to be blamed for its initial failure. One was the front control panel and another was an electronic component in the rear of the unit. Neither replacement improved the performance so it was money wasted, and on top of that, we bought the second 2351 because, 20 months ago, we didn't have sufficient battery capacity for any other option.

The good news is that everything Lewster says about marine fridges is widely agreed upon in the general industry, and therefore likely to have truth to it (not that anyone ever doubted Lewster). And I should know this, because I've talked on the phone today with everyone and their dog. There is consensus that the Danfoss compressor fridges are the only way to go.

I also encountered an acknowledgement that the Norcold does fail according to the mechanism discussed previously in this thread. One sales guy tried to introduce me to the Norcold option and I said, "Waitaminute - I've seen pics of fried circuit boards on the internet." And he said, "Yeah, that happens - we have had returns of Norcolds."

Duh. A little reliability would make me very happy right about now. I'm not sure yet how we will resolve this situation.

[Wolf Alaska]

The Norcold all electric refer, compressor design, in my Type B is 20 years old & still works fine. A propane refer can be ruined in 20 minutes.
Let's Roll !
Wolf

[InterBlog]

To this day, we don't understand the 3-way Dometic's failure modes, and we've owned two of them. Last night, we did basic investigation and trouble shooting, as well as soot cleaning, and could identify no specific issue that was preventing it from working. A nice flame comes on and sustains perfectly, but almost no cooling results. Nor did any intervention of ours have any positive effect.

On this one, we are fairly confident that no action of ours contributed to the malfunction (sometimes we accidentally screw things up, but not now). We simply hadn't used the rig recently due to our too-hot summer - I turned on the fridge as an efficient way of burning down the on-board propane supply in advance of LB_3 receiving his air suspension kit, which will require us to drop the generator, which will require us to disconnect its valveless propane line, which requires that there be no propane present. And all of a sudden in the absence of any human activity, I noticed that the fridge suddenly stopped working. Better to find out now than during the upcoming 6,000-mile trip.

[InterBlog]

Well, the OP wanted to know about the feasibility of 3-way refrigerators. There's certainly an earful in this thread.

Quote of the day goes to Dometic, whose service manual says this:

"A refer (sic) that chases the out-side (sic) temperature is improperly vented or has a weak cooling unit."

And my response is:



What the hell is "weak"? And how does a device that was so strong initially (almost too strong, as it was freezing our food in the fridge section) suddenly become "weak"?

As my husband said last night, "It's got a strong flame, plenty of propane, and it's a closed system with no moving parts. It has NO CHOICE but to work."

Except it doesn't work, apparently because it has mysteriously become "weak".

We are being extra-thorough with the diagnostics, given that this is the second Dometic 3-way that has died on us. Following Dometic's own protocol, we basically short-circuited it so that it would run full blast without cycling (in case there's something wrong with the electronics). The problem is definitely a cooling unit that has somehow become "weak".

My advice: avoid Dometic absorption fridges like the plague, if you are able to do that (which requires a battery bank capable of running an all-electric).

[Lotus54]

I am just learning (a little) about absorption refrigerators. I've read that unless it is very level, it may not circulate the gas/liquid properly.
If moving, it will circulate easier.
(Well, that is what I read).

it does seem to be that way for mine- sometimes it won't work on AC (I can feel the heat element working) and other times works excellent. Right now I'm speculating it is due to it being parked not particularly level.
I know it doesnt' take much propane to operate it, but it would be nice to run on DC when driving to save propane (and have propane turned off when driving).

It would be interesting to see if taking a short drive on a bumpy road makes your frige start cooling again?

[InterBlog]

Your comments underscore one of the big problems with absorption refrigerators - anecdotal reports are literally all over the map. Many people report fabulously effective operation irrespective of small changes in slope or movement - such was the case for us in the first 20 months of owning this one, EXCEPT, movement basically caused it to shut down during the day when we were on the road. But a good number of other owners report that they can't get their absorption refrigerators to work no matter how much they mess with them (varying slope, movement, etc.), and they never know why.

Whatever degradation caused our 20-month-old cooling unit to become "weak" also appears to have also made it hypersensitive to slope. Previously I could begin packing up the night before for an early departure, and the fridge once turned on would be 28 degrees by morning, with our Interstate parked in our driveway.

Today, that very same driveway slope is apparently a contributing factor in disallowing it to get below 44 degrees. LB_3 put its front wheels on blocks last night, thus flattening the slope by a whopping 1.7 degrees (how fun - I got to do trigonometry for the first time in years to calculate that). 1.7 degrees closer to the horizontal enabled it to get down to 36 degrees. But as soon as I dropped it off the blocks - boom - right back up into the 40's.

The world is not perfectly flat, so this has become an intolerable operating constraint.

As for the cause of the "weakening", my best theory at this point is that the water portion of the ammonia charging mixture corroded some interior surfaces, perhaps making it part way into the primary coil, and the physical scale of corrosion is partially obstructing and preventing efficient ammonia circulation, thus leading to fridge temperatures in the high 40's to mid-50's even as the outdoor and interior coach temps have not risen above 85 degrees (Houston is in an unusually cool weather pattern right now).

*IF* that's true, then it would represent a defective design on Dometic's part. Maybe they had a bad batch of metallurgy or something. Or perhaps they added insufficient corrosion inhibitor (sodium chromate) to the system. Or something.

Here is a wonderful 2.5-minute vid on how these fridges work, for anyone who is interested.

https://www.youtube.com/watch?v=udeSVyx6_9A

[55AS]

Originally Posted by InterBlog

My advice: avoid Dometic absorption fridges like the plague, if you are able to do that (which requires a battery bank capable of running an all-electric).

I have now had two Norcold absorption fridges, which cost a bit more than the equivalent Dometic, but seem to be much more reliable. All electric offers some benefits but price barrier is substantial if you consider the cost of compressor fridge, larger battery bank and solar system.

[Pahaska]

A common failure mode in absorption refrigerators is hydrogen leakage at the welds in the system. Hydrogen, being a very small molecule, can leak through a porous weld faster than the balance of the charge.

The symptom of hydrogen leakage is a freezer that still gets cold and a refrigerator portion that will not get down to temperature. Because the charge enters the freezer portion first, all of the ability to absorb heat is gone by the time it gets down to the refrigerator coils and fins.

I had two Dometics fail over the years in just that fashion. I replaced the second Dometic with a Norcold that did well up until I sold that trailer.

I like the ability of the compressor refrigerators to cool rapidly. I have turned mine on at the storage yard and it is down to the mid-40s by the time I drive the 10 miles home. No more waiting over night.

[InterBlog]

Pahaska is rising to near-Protag status here with his forensics.

I am thinking that SOMETHING is fundamentally different about this versus 20 months ago. I popped it down off the blocks this morning, and right now, 8 hours later, I'm getting freezing conditions in the freezer but still far too warm in the fridge.

LB_3 speculates that perhaps the bounce off the blocks may have dislodged some partial obstruction or restriction, and thus improved the circulation (it's hard to get down without a little bounce, especially if the blocks are wet and slippery as they were this morning).

Pahaska's speculation would explain the latter condition quite nicely.

[LB_3]

Absorption fridges contain some wicked source of black magic. When I was a kid camping with my uncle, I couldn't understand how fire could make things cold. The explanation I got was 'magic'. 15 years later in my thermo classes I discovered that my uncle's magic fridge violated both the first and second laws of thermodynamics. That's not Glenda the good witch style magic, that's Marie Laveau style darkness and I want it to leave before 'another van done gone.'

[mimiandrews]

There's an old procedure called "burping" a fridge. Some think it's an old wives' tale, and some swear by it. The procedure involves turning the fridge upside down or on its side in a specific sequence of moves.

I am a bit of a believer, because my fridge sat for a little over a year after we had its cooling unit rebuilt--just enough to be out of the repair shop's warranty period. It had worked fine after the cooling unit was reinstalled, but other repairs the trailer needed caused it to sit.

What did we have to lose? We looked up the burping procedure and tried it. The fridge has worked ever since we did it.

I don't remember the exact sequence of moves for the burp, but I'm sure a search will produce several versions.

I also found that I could run the fridge in my workshop for test purposes from a barbecue regulator on a 20 lb propane bottle with a battery charger for a 12 volt supply.

[InterBlog]

Originally Posted by mimiandrews

There's an old procedure called "burping" a fridge.
....

I also found that I could run the fridge in my workshop for test purposes from a barbecue regulator on a 20 lb propane bottle with a battery charger for a 12 volt supply.

Based on my experience yesterday, "burping" would not surprise me. Everything else we tried, which ran the complete Dometic servicer's list, did not produce a result. Bouncing it off the blocks appeared to produce a result. Or else it was a timing coincidence and the fridge just happened to receive a directive straight from God at that exact moment.

Good to know that second part about bench-running. We are leaning in the direction of going all-electric, given that the fridge itself is still not functioning even if the freezer has now iced over. But Dometic told me on the phone yesterday that parts AND labor are both covered on this thing. That is not what my PIECE OF PAPER says, but LB_3 and I suspect that Dometic is under considerable competitive pressure from the manufacturers of electric refrigerators and maybe they had a change of heart and decided that they want to please their customers in order not to loose them. Because, really, saying that the parts are covered but not labor is basically saying "congrats - you are screwed".

So I was thinking of maybe making my owed warranty claim but then selling this gaseous albatross to offset the cost of the new electric. In which case I'd need to be running it on a bench to demonstrate to a buyer that it does work.

[InterBlog]

Here's an example of why warranties are not really "warranties" as a reasonable person would interpret them, whether they include labor or not.

I called the two closest authorized Dometic service centers to see about having our fridge evaluated. The closest, Holiday World, cannot offer an appointment until August 29 at the earliest (today is June 29). Remember also that, even if they diagnose an actual problem covered by warranty, it's then another 1 to 2 weeks on top of that to actually get the part shipped in and achieve the repair. So it could be as much as 10 weeks required to remedy the situation. Or longer if the part is back-ordered.

The other service center, an independent, is somewhat better - they are making warranty appointments about 3 weeks out, and again, with an additional 1 to 2 weeks for repair. So, 4 to 5 weeks out on situational resolution, in a best-case scenario.

It makes a strong argument for buying the best equipment possible at the outset, with less regard given to price and more weight placed on reliability. Those time frames are not realistic for anyone actually wanting to use their rig. What if we were on the road when an appliance such as a refrigerator fails? It's over at that point.

FWIW.

[Monza]

Here I had thought I'd narrowed down my research to replace my vintage Dometic fridge with a 12v only Norcold and I run across this thread. I can also get a deal through a RV parts supplier friend on a Norcold and these fridges are not cheap.

What are some of the 12v fridges to look at? Give me your top picks, please.

Thanks

[LB_3]

We're looking at the Vitrifrigio C115i. But there are a couple other marine refrigerator manufacturers out there.

We were attracted to the marine industry appliances because there is less price pressure on the manufacturers to cut corners as is so common in the RV industry. And as one of the posters reminded us when we asked a similar question on the sailing forums, sailboats may be days from the nearest grocery store so they demand a much higher level of reliability than RV owners.

[InterBlog]

Lewster advised me to look at either Vitrifrigo or Isotherm.

Cruisers Forum people had even-higher-ended suggestions than those two (SEVERAL thousand dollars range) if I wanted absolute unquestionable reliability. But I'm looking for a sweet spot. Not the low-ended Dometic but not the thing I would need to cross the Atlantic Ocean with confidence, either. LOL, I'm fixin' to cross North America, but not the Atlantic just yet.

Marine industry people appeared to prefer Vitrifrigo. I got that from a veteran wholesaler contact, not a retailer trying to sell me something. For any given size, Isotherm is several hundred dollars more expensive and they feel it's not really worth that premium.

For our sized existing cabinet cut-out, we may have to do some serious manipulation of our face trim, but we MIGHT be able to get the Vitrifrigo in without tearing down the cabinet entirely (I'll report back). The numbers look like this (below), but the numbers are obviously lying - different figures were cited on different websites. According to published figures, the old Dometic never should have been able to fit in the first place, and it did.



You can see immediately why I chose the Vitrifrigo. Bigger freezer. That alone was the deal-maker.

It is also *GORGEOUS*. The quality is visibly better than the Dometic. The wholesaler cracked open a box and allowed me to examine it in his warehouse. Having been thusly delighted, I phoned up my favorite local retailer and had them process a P.O. for it, such that I carried it right out of the wholesaler (they were firm about selling to dealers only; some wholesalers are, and some are not). Then I stopped at the retailer on my way home to sign the credit card receipt. It's good to live in a yachting community.

I'm so excited.


No doubt there will be cursing during the upcoming cabinet surgery, but I'm cautiously optimistic that this decision will finally put the kybosh on our recurring fridge problems.

Look at that big, beautiful box just waiting to be unpacked and installed...

[Lotus54]

Wow!
I'll be looking forward to another of your great Blog entries on the install.

No way I could go that way at this time (just one house battery and no solar) - although for traveling it would probably work just fine. Alternator powering all day and just night for the batt (or Shore power when that is being used).

Sounds interesting.

Mark

[Monza]

I asked the Canadian distributor who sells both Norcold and Vitrifrige, you'll like this answer about Norcold problems and what is best:

"Norcold's come backs are at 80% right now they are working on there problems
The Vitrifrigo line is the best. Units going come backs are one out of 300"

I ordered a Vitrifrige.

[InterBlog]

Originally Posted by Monza

...

"Norcold's come backs are at 80% right now ....

That explains nicely why people are raising hell on other forums right now. That's just criminal.

As was mentioned previously by my husband and/or me, we live in a unique area - there are 90,000 (!) registered pleasure boats on Galveston Bay. It's hard to even wrap the brain around a figure that large. Because of this, word gets around. If a situation is even remotely connected with boating, somebody here is going to know it, and somebody else is going to sell whatever that situation requires.

Anyway, it was just one local wholesaler that I visited yesterday, and he had the day before just received seven more of the Vitrofrigo C115IDB4-F units. He hadn't even had time to shift them off his loading dock when I showed up to cart one of them away.

Mind you, Vitrofrigo makes a whole diverse line of fridges in many different sizes. That's just one unit, and they are moving them so fast that they're receiving multiple deliveries per week, of that just one size of unit.

A LOT of people are choosing this fridge, in other words. Let's hope that they live up to their reputation.

[Sebtown]

Mark, you are like me, one battery and no roof top solar. We do fine on travel days and have a 100 watt solar suitcase for non travel days. Just spent five days in one place and never fired up the generator. I admire Interblog and LB_3 for their endeavors but not having their abilities and skills I have to sit on the sidelines and enjoy their progress while I suffer with my less than great but usually adaquate Dometic fridge.