Two-Way Refrigerator?

[73shark]

There doesn't appear to be traces in parallel w/ the jumpers unless it's a multi-layer PWB and they're buried.

IIRC, the whole tin whisker/dendrite problem was exacerbated by the forced shift to lead-free solder.

[rmkrum]

That's why I keep a good supply of the real, not lead free, Kester 63/37 lead/tin RMA solder in assorted sizes handy. It doesn't get the fluffy white corrosion either. (Yes I conformal coat the boards when I'm done, of course)

I'm one of the few real engineers that can solder well enough to satisfy the grumpy QA inspector. Even surface mount stuff. (Yep, weird)

[InterBlog]

Back to the OP's original question, I suggest that anyone who is considering a 3-way fridge first read this thread on the Base Camp, which has the very same model of Dometic 3-way as the Interstate (those that were built with 3-way fridges). I don't think that I've seen that much misery expressed in any other single thread, and increasingly, it appears as if the BC's fridge problems are model-wide. Meaning, pretty much every BC produced is hobbled by this problem.

Some of the problem appears to derive from inadequate venting, and that much is on Airstream. But there's also the compounding issue that, IMO, the Dometic RM2351 just isn't that strong of a fridge model to begin with. The venting problem might not have been catastrophic if the danged thing had been built better to begin with.

There might be a more robust 3-way somewhere out there in the consumer market, but if there is, I don't know what brand that would be.

We are continuing to test our Vitrifrigo under end-member extreme conditions. With overnight lows around 80 degrees and daytime highs approaching 100, what the marine salespeople originally told me is proving to be generally true - the compressor is going to run pretty much full-time to keep up with that kind of demand. But it does seem to be able to keep up. Last night it ate about 7% of our battery capacity in the process of keeping up, but I have it at a disadvantage because it's totally empty as I'm testing it, meaning there is no food and drink load to "hold the cold".

I picked up this cute thermometer for about ten bucks on Amazon:

[InterBlog]

Oh my freakin' gosh (OMFG), I don't believe this.

But first, a recap.

This thread originated because the OP was asking why Airstream did not use 3-way fridges given that the 2-ways draw so much power, to the point where it's questionable whether the rigs can handle those demands without battery upgrades being needed.

In this thread, there proceeded to issue forth a stream of criticism about the 3-ways, including the story of how LB_3 and ditched our second, almost-new, under-performing 3-way in favor of an all-electric Vitrifrigo.

Circle back around and I finally turn my attention to the fact that I need to get our de-installed 3-way carcass off my garage floor and out of my house, finally, because it's not paying rent.

But before I decide what to do with it, I want to run a little experiment. As I was researching what might have gone wrong with our almost-new Dometic RM 2351, I kept encountering references to "burping" a propane refrigerator. Except there was a discrepancy. Some people swore that burping was the answer. Others claimed it was an old wives' tale with no basis in fact.

One way to find out. Flip that sucker upside down and see what happens.

As it turns out, the process actually sounds more like vomiting than burping, but I understand the origins of the reference (anyone who has ever burped a baby would).

Anyway, here's the outcome -- and I don't even have any food or water load in the refrigerator right now. We just turned it on and left it overnight in a hot garage (we're in the deep south so, yes, the garage often won't fall below 80 in late October).

I don't regret upgrading to the Vitrifrigo. It makes better sense for our van. But how frustrating that so many people struggle with 3-ways when, in at least some of those cases, all that needs to happen is that the thing be turned on its head for a while. This is the type of performance that we would always see 2 years ago when it was new - instant descent into the 20s Fahrenheit, even in warm conditions, even without a food load in it to "hold the cold".

[InterBlog]

Addendum here which is not directly related to the thread per se, but this advice might be useful to people generally because there's a lot of money at stake:

For our stick-and-brick house, we bought a Sears Kenmore Elite refrigerator in 2015. One of my primary motivations for doing so was that it came with a 10-year warranty on the compressor (parts, not labor) and a 5-year warranty on the refrigerant system.

It has proven to be a complete lemon. The ice maker failed after less than 4 months. The compressor has failed after 3 years. The compressor replacement parts are being provided to us at no charge, but I've been quoted $388 for labor.

Furthermore, the repair tech says that the failure rate of these "10 year" compressors is extremely high. His demeanor suggested that "extremely high" might mean the majority of them (echoes of the Norcold issue mentioned earlier in this thread). He has a small service area (just our municipality) and stated that he replaces at least one compressor per day, each and every day, on fridges that are still under parts warranty.

That statement coupled with the obscene labor charge got me to thinking that the game may have really changed now.

It used to be that if you bought a product with a longer warranty, it was probably a more robust product. But if a manufacturer can install inferior parts (cheaper) but then charge outrageous labor rates, they come out ahead financially in the long run even if the parts are "free". "10-year warranty" might have morphed into today's version of a sucker sale.

Our Kenmore was about $2,400 (it's a 4-door). I told the tech that my next fridge purchase was going to be one of those modest old-style top-freezer models which start about $600 retail. That way, every time a "warrantied" part fails, rather than paying successive obscene labor charges, I can just throw the entire fridge away and start over with a new one, and then *I* will be the one to come out ahead financially rather than Sears.

He replied, "Yeah but wouldn't one of those small old-style ones look funny in your kitchen?"

Bingo. The way they extract money in this scheme is to promote showboat-style fridges that are perhaps inversely correlated with reliability. I didn't buy our Kenmore because it looked nice. I bought it because I thought that "10 year warranty" actually MEANT something in implying a standard of reliability.

So as we wait 2 more weeks for this repair, our sole fridge at the moment is the old Dometic 2351 which got taken out of our Interstate during the Vitrifrigo replacement job, and is still sitting on our garage floor because I had not gotten around to Craigslisting it yet. At this point, I think we might actually install it in the garage and keep it as a permanent back-up because we obviously need one. Bonus for those of you who decide to upgrade to a Danfoss-style compressor fridge in your Airstreams. Your ol' dinosaur propane fridge might serve you well at home rather than on the road.

[Boxite]

While attempting a personal repair on our Kenmore OverPriced Model I found a local appliance-repair shop that shared his insight with me on parts and mfr'g of Kenmore units: They are made by Whirlpool, Frigidaire, LG, GE, and others...and the key to finding out who makes a particular unit is found in that loooonnnggg Model-Number. He suggested he sells most parts for the LG and Frigidaire made units and the Whirlpools seem to be the most robust.

He also pointed out that ordering the part I need (the evaporator-fan sometimes stops running on a "dead" portion of it's armature-coil and was difficult to diagnose because sometimes it'd stop on a good coil and would fool me into believing the fan was OK because it'd start back up or continue to "run"... but overnight the freezer would defrost and the fan would not be running.... it was a pain in the arse to diagnose, but...) anyway... he pointed out that buying that replacement part using the exact part number in the Kenmore parts catalog would cost me $126.... but buying the Frigidaire part number would be $84.... but using a "universal replacement" fan was only $21. Including 2-day shipping.

Since I'd already relegated that refrigerator to the task of beer-keeping in the garage I took the $21 choice...and now 3 years later it's still running just fine!

Draw your own conclusions.

And, Oh Yeah.... the "universal unit" only difference from the more expensive parts was that I had to use crimp connectors to make the electrical connection instead of the part coming with a "molex" plastic connector to plug into the existing harness. (Cut off the existing molex on the refer and used butt splices.)
The mounting bracket, everything else was identical...except THIS ONE WORKS!

[InterBlog]

Well the interesting thing in our current case is that the parts are being shipped directly to us and the repair tech will meet up with them later.

The parts can be shipped to us because they are "free" due to the warranty coverage. Theoretically, we might be able to save ourselves $281 by doing our own installation once we have them in-hand, but the job will involve cracking open the freon system which is not routine and for which we do not currently have certain tools. And which action might void the remaining 7 years of our warranty, if we do it ourselves.

That is, if there **EVEN IS** a remaining 7 years of warranty after this event. My service ticket explicitly notes that this upcoming work will only be warrantied for 90 days. So it may be the case that only the ORIGINAL compressor comes with a 10-year warranty. Not its replacement. There is simply too much fine print for me to figure it out at the moment.

[InterBlog]

Another semi-relevant addendum. Our Kenmore Elite stick-and-brick house fridge died in March. It is now June, and it's still not fixed, despite 5 service calls. The only reason why I haven't taken Sears to small claims court is that, while that approach may be expedient, it may not be my most efficient course of action (details omitted but feel free to PM me if you ever face a similar nightmare).

Anyway, we've been living out of the Dometic RM2351 for most of the past several months. Generally what happens is that Sears gets the Elite working for anywhere from a few hours to a few days, it dies again, and we call again.

They fixed it temporarily again yesterday, and it will work long enough for me to defrost the garage Dometic. LOL, can you tell from this photo below where my air leak is?!

A testimony to the viability of a 3-way fridge that has been properly burped and stabilized. It is now above 90 degrees every day in the garage, and it's still going strong after months of this nonsense.

[rowiebowie]

Pardon me if your horror story on home fridge reliability makes me feel somewhat better. I don't mean that in a bad sort of way, it just puts my life's aggravations into perspective. Makes mine seem not so big. Still frustrating, just not on your scale, thank goodness.

I hate that we've evolved into a throw away society due to poor initial craftsmanship, unreliability of service techs to do proper repairs, and failure of companies to stand behind their product warranties. But that's where we are today.

I'd read about "burping" 3-way fridges and since it's such an easy, cost-free, fix (in some situations), it should be promoted more as a first-line approach since it really has no down-side.

Regarding your old Dometic air leak, when I reversed my Novacool door I used the dollar bill "trick" to determine the seal was tight all-around. But I'm curious. What does freezer frost tell you about where your seal is leaking? Isn't the freezer where all frost originates?

[InterBlog]

The Dometic freezer door does not seal as well on the left side. And with our coastal humidity, well, you can see the result. I might try adding some weather stripping there.

I did not know this until recently, but LG (which manufactures fridges for Sears) now runs coolant lines through the whole body of the fridge. In the Before Time, it was just a pair of exchangers with one fan apiece for the fridge and freezer portions, but now I guess they shoot for whole-fridge coolant distribution (which is dumb). This is what leads to fridges becoming literally unfixable - there are too many line runs to isolate individual freon leaks, so they just have to scrap the whole fridge whenever a pinhole leak develops.

Sears has a very specific procedure by which they verify that a warrantied fridge is unfixable. I could probably take them to court successfully but the whole shebang might take just as long as this condemnation procedure, after which I'm told they will give us a new fridge.

Anyway, going forward, that's something to be on the lookout for with respect to two-way RV fridges. DON'T ever get one with widely-distributed coolant lines, if possible. Given that van fridges are smaller, I'm hoping that manufacturers are not motivated to introduce a similar fatal design flaw.

[InterBlog]

Here's a "watch and learn" moment for everyone who has a freon fridge, whether home or Interstate or trailer:

We are almost three months into this problem and FIVE service visits were required before Sears finally located a leak in our Kenmore Elite.

What I'm doing in this pic below is that I've got the black light and the glasses in my left hand, cell phone taking pic through the glasses in right hand.

Can you see the fluorescence? There's a leak in that location.

Now, why it took FIVE service calls to reveal this problem, I do not know. But don't let this kind of thing ever happen to you. Make them put the dye in the system and then black light the entire plumbing FIRST, before they start pulling and replacing parts at random, as they did with us.

[InterBlog]

I got an email from a SOB Class B owner this morning. He had to make the decision to either trade in his T1N for a new Sprinter-based model, or upgrade what he has. After researching the NCV3 reliability issues, he wisely chose to keep his T1N and commence with upgrades.

He touched base with me because he wanted to verify that our Vitrifrigo fridge had lived up to our expectations (answer: resoundingly yes). Vitrifrigos are not available in his area, so he's planning to drive 500 miles round trip in our southern heat to buy one from the same vendor who supplied ours.

It's neat when blog posts like this one here actually help people to make informed decisions in their lives.

[InterBlog]

Originally Posted by 73shark

You are correct that the dendrites or whiskers are tin. The removal of lead meant more tin. Another downside of lead-free solder is that a good joint appears the same as a cold solder joint when using tin-lead solder.

Found this on the interweb:
"Tin whiskers! Lead was originally added to solder because of tin whiskers. No one is really sure why they grow, but they can grow at prodigious rates and cause failures. There is no clear, repeatable correlation, but elevated temperature, humidity, and voltage seem to have some correlation. Tin whiskers have been known to grow right through conformal coatings. This is especially a risk in modern high density, low current circuit boards."

Once again, I find myself wondering if we forum junkies might have played a small role in product evolution. More than 5 years after this comment above was posted, here’s a screenshot below showing something called a “conformal coating”, which is essentially a type of plastic that isolates circuit boards from the environment. Why would that be added?? Because it helps prevent the formation of tin whiskers, or other products of corrosion or material degradation (this quote above notes that tin whiskers can sometimes grow through, but hopefully with 5 more years of evolution, that possibility has been addressed).

This is the type of countermeasure that might have prevented the product failures discussed here in this 2017 thread. In no location where I’ve seen circuit board failures was there any conformal coating visible at all. This came up in the context of the EcoFlow Delta Pro portable lithium battery, which is discussed in this 2023 thread.

See how shiny the surface is? That’s the protective coating.

[Lotus54]

Just so you know, conformal coatings have been used for decades.

For boards that are subject to extreme environments, I used to spray with ACF-50 for extra protection. Great stuff and never had any sort of reaction/issue using it.

[InterBlog]

Originally Posted by Lotus54

Just so you know, conformal coatings have been used for decades.

For boards that are subject to extreme environments, I used to spray with ACF-50 for extra protection. Great stuff and never had any sort of reaction/issue using it.

True, but I’ve never seen one like that shown in the screenshot. Perhaps I just haven’t seen very much, but we did tear apart two RV refrigerators, our original converter (twice because the first un-coated one shorted out and started a fire), and then built our own whole-van electrical system. Nothing so thickly coated was part of that process TMK.

What makes a manufacturer decide to apply them, or not apply them? Is it by whim, or is there a technical standard?