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Old 05-29-2007, 09:11 PM   #15
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[quote=BillTex Hello, saw your post on keeping fridge level-I see by your info you are a professional/expert on RV cooling!

Had a problem this past weekend, the fridge in our 89 Excella always worked fine, this weekend while boondocking, the freezer was very cold, the fridge was not cooling well at all. I thought we were pretty level, had plenty of propane, etc so I was a little stumped; why the freezer but no fridge?

When we got home I set up in the driveway, checked that the camper (and fridge) were level. I did find out that the level mounted on my camper was not calibrated perfectly, so we were probably off 1-2". After leveling, I let the fridge run on propane for a while and everything seemed ok.
Is it possible that being 1-2" off level was causing the fridge to run warm?
Yet the freezer still worked fine?
Aren't they cooled by the same motor?]

Bill,

Just a quick tutorial on RV absorption refrigeration. There is no motor or compressor like household units have. There are a mass of tubes filled with ammonia and hydrogen, and a bright yellow anti-corrosive called sodium chromate.

This solution is heated in the boiler section, above the propane burner or by the electric element also located in that section. The solution rises to the condensers at the top, and the cooling process begins (I can explain exactly what happens, but it is very lengthy, PM me if you're interested.)

The solution then proceeds to the low temperature absorber, and then down to the high temp absorber. This is where the heat transfer from the box takes place, and the freezer and fridge sections get cold.

The solution then continues downward to the leveling chamber, or accumulator, and the process starts again.

New units need only to be level to the point that the RV is comfortable to walk in. Older units need to be 'LEVEL', that is to say, bubble level! Since gravity plays such an important role in the cooling process, you can see why being level is so important.
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Old 05-30-2007, 07:03 AM   #16
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Thanx for the fridge education Lew!

Is it likely there would be a difference in performance on propane vs electric?

I have only run propane for maybe 1 day at a time before and that is usually while towing, this is the first time we ran 4 days while stationary on propane. By day 2 it was noticeably warmer...

I am pretty sure it was a matter of levelling; we were about 1" off port/starboard and 1-2" off bow/stern. Maybe this combo was just enough to cause problems?

Never worried as long as we were within 1" or 2" before, but we are usually running on AC, not LP, and the beer was always nice and cold...

I have added a carpenters level to to my tool box and will dial it in more precisely next time (frame, fridge, etc) we are boondocking. I should have calibrated my AS level before, it never occured to me it could be off as much as 2"!

Thanks for your insight, Bill
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Old 05-30-2007, 07:41 AM   #17
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Bill,

I forgot to mention maintenance. It's a good idea to either clean, or have someone clean the LP burner parts of the fridge. The can and do get rusty and if not properly functioning, will degrade the performance.

A very overlooked part of the fridge is the spiral baffle. If you have a manual and check in it, you will see that it is a rectangular piece of sheet metal twisted in a spiral pattern. This VERY IMPORTANT piece resides INSIDE the flue tube, also located directly above the LP burner section.

It is suspended by a precise length wire and often gets rusty and or eaten away by rust. This little piece could also be responsible for degrading the performance of your fridge. The only down side to this comes in trying to remove it to clean it.....usually involving complete removal of the fridge. It IS accessible in some trailers (like mine) thru the upper fridge vent door.

If your unit is working well on electric, then this test is not necessary, but I usually will open the control box at the back of the fridge, find the 2-1/4" push connectors that come from the 120VAC heating element, remove them (mark which color goes where) and will make a pig-tail connector and plug the fridge electric element DIRECTLY into a 120VAC outlet.

I then run the fridge, having effectively removed the controls from the picture, and see what the unit does. After running overnight, it should be VERY COLD in the freezer and nicely cold in the fridge. Remember, you have no temp control during this test, so don't leave anything in the fridge that might freeze, 'cause it might freeze!

Good Luck!
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Old 06-19-2007, 01:15 PM   #18
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Quote:
Originally Posted by lewster
[
New units need only to be level to the point that the RV is comfortable to walk in. Older units need to be 'LEVEL', that is to say, bubble level! Since gravity plays such an important role in the cooling process, you can see why being level is so important.
Hi Lew-can you define "older"? As far as I know my 89 has original fridge. I finally broke down and brought it to the local dealer ($).
They have been running it over night and so far they have the same results as my test; cold freezer, warm fridge.
So I may be faced with replacing my fridge...

Any further advice?

Thanx, Bill
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Old 06-19-2007, 08:54 PM   #19
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I'll have to check the specs for your unit....what is the model #?
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Old 06-19-2007, 09:33 PM   #20
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Thermocouple

My old Argosy had a unit in it that had the same problem and I found that the thermalcouple was touching one of the cooling fins. I moved it away and wala - no more problem.
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Old 06-20-2007, 07:40 AM   #21
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Lew, don't remember the model # and it is at the shop right now...

David, I will call them and ask them to check thermocouple...thank you!

Bill
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Old 06-20-2007, 09:58 AM   #22
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Dometic or Norcold?

Lew, fridge is (was) model 2601.
Just talked to dealer, they have tried all the tricks, "shocking" (? not sure what that is), turning upside down, checked thermocouple, etc.

Conclusion? We need new fridge...

So now the question is; Dometic or Norcold?

And which model is preffered?

Thanx, Bill
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Old 06-20-2007, 08:25 PM   #23
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BillTex,

Dometic has a 3 year warranty on new units and is presently under a 1,000,000 unit recall and is made in Sweden (part of the Electrolux Group)

Norcols has a 2 year warranty and has also had recall problems in the past (but their recall actually chanced the entire cooling unit in a bunch of fridges, not applied a band-aid!) and is made in the US.

TOUGH CHOICE!!
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Old 06-21-2007, 07:00 AM   #24
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Thanx Lew, I didn't really have a preference but gave the dealer the go-ahead w/Dometic as it will fir the space exactly. I did remind them of the recall (they were well aware of it).

FWIW, the dealer, so far has been very good to work with. I usually try to do most of the work myself, but wasn't up for a job like this.

Boy, is that one expen$ive fridge!

Thanx for your help Lew.
Should have camper back Fri or Mon...too bad, we wanted to go this weekend...

Bill
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Old 06-21-2007, 12:21 PM   #25
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Hi Lew, do you know what year Dometic switched to the round style accumulator and stopped using the square style?

I believe this is what made the difference between a fatal failure or temporary loss of cooling when off level?

I am just curious...

Thanx, Bill
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Old 06-21-2007, 01:02 PM   #26
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Does running an older fridge off level just affect performance, or can it also cause damge to the unit?
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Old 06-21-2007, 02:29 PM   #27
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My interpretation of the Dometic literature is; if you run the “old style” (still haven’t figured out what year that changed) square type units off level, and you get a blockage, it will be fatal. Yes, you can “burp” it and it may run temporarily, but ultimate you will experience crystallization and the unit will fail.
The new (what year?) round style units, if run off level, may experience poor performance, or maybe even fail, but once you run down the road again and re-mix the ammonia solution, they will self correct.
I also gather that the old units will tolerate less off center conditions than the new units. So, while I may be bummed about how much $ I just spent on a new fridge, it should be a better unit and more tolerant of off level running…

I am sure Lew will chime in and set us straight, but that is my understanding at the moment!

Bill
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Old 06-24-2007, 10:15 PM   #28
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Hi Bill,

I'm not sure when they changed the design, but an 'old' style unit requires 'bubble level' to operate correctly while the 'new' units need only to have the RV 'comfortably level' operate correctly.

I checked my production notes but there was no mention of when the change was made. I'll call my friends at the Dometic hotline to see if they have an answer in the next day or so..............
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