Dometic fridge wide temp swings

[Denny B]

Our fridge does not have a temperature select button, and the slide has no labeling.
Our manual states that the temperature is factory preset. Moving the slide up as high as I could get it has made a dramatic difference.
I'm very grateful for the F R O G, and all the information I have gotten from the group.

[KBUZ]

Back from trip. Still temp issues. If you have more info turbs? I'm ready!

[TURBS]

I'd go with fans! [emoji6]


2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"

[The_Rhino]

My 5 year-old 8 cu. ft. Dometic 2852 had difficulty maintaining 40 degrees although the freezer was fine. I got the same results on both propane & 110V. Also got the same results with a new thermistor (dial type from 3rd party), fans added to the back, fan added inside, etc. I could replace the cooling unit with an Amish-built one for $480, but IMO it would still have difficulty cooling & it was also a little small for our family of 5. So......

I replaced it with a new (scratch & dent) 11.8 cu. ft. Whirlpool residential fridge that I found for $300 at a Sears Outlet. (The small scratch on the side is hidden when installed in our TT...) We used it for the first time over the Memorial Day weekend and my DW LOVES how roomy it is. It even holds 2 gallon-size milk/juice jugs in the door. Our kids can open & shut it all day, just like the fridge at home, and it maintains 40. The freezer has a separate dial so our ice cream is just right...

Biggest plus - I can turn it on & load food just 1 hour later. Sure beats 24 hours...

This week I am installing a 2000W inverter ($100) that will keep it running on long trips. I already have (2) Yamaha 2000 clones for boondocking & will upgrade to a (2) battery setup if needed.

New TTs show residential fridges as an "upgrade" folks pay extra for, so I don't think having a residential fridge will hurt resale value...

[Stormrider151]

I've been doing a little experimenting with the inside fans. I have the same fans Turbs does. I started out with them attached to the fins. That helped some but I removed them from the fins and set them on the top shelf pointed down the side. This helped a lot. Usually it takes 2 days to get the fridge to operating temp. This way it only took one. However, with the sun beating down on the wall outside of the fridge the temp went up to 45. Next stop is fans in the back. I think this is just the nature of the beast.

[Paul GA]

Turbs, on your outside fan, is that from lower outside vent looking up? What is the fan mounted to?

[TURBS]

Originally Posted by Paul GA

Turbs, on your outside fan, is that from lower outside vent looking up? What is the fan mounted to?

From the upper bent looking down.
It's mounted to a flange not quite half way between the two vents.


2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"

[pgandw]

The issues of fridge temp swings are pretty common in standard (not high wall) PUPs and A-frames. We have small, continuous-run fridges with no thermostat. The exhaust vent is typically 3-4 inches above the intake vent - and both are on the side of the camper. There isn't much chimney effect with such little vertical spacing.


The issues really hit home with me while camping in our A-frame in Nebraska last October for 4 days/3 nights. My wife was retrieving something under the sink, and brushed against the 1/8" plywood divider between the fridge compartment and the sink compartment. The plywood was actually hot to the touch. She had me check and confirm that the divider was hot. I knew the heat was coming from behind the fridge, and decided I needed to do something about it. I also didn't have the same flow of hot air out the top vent of the fridge that I was used to in our previous PUP.


When we got home, I did some more checking. The fridge chimney cap was a small pipe oriented across the chimney at about a 45 degree angle from horizontal. The high end of the cap pointed at the inside of the trailer, not the exhaust vent. And there was about 3 inches of fridge compartment beyond the chimney that was essentially dead space with no vent access. There was also dead space in the compartment above the vent.


I rotated the chimney cap 180 degrees so the high end faced the exhaust vent. In this way the chimney properly served as a venturi to improve the air flow across the coils and out the exhaust (as Dometic intended). I bought some Reflectix and used that to form a new ceiling in the compartment to stop heat collecting there. The Reflectix was tucked between the cooling coils and the back of the fridge, arched just above the chimney, and across to the top edge of the vent. I duct taped the Reflectix into place. On both ends of the compartment, I lined and formed a rounded duct that again led to the edge of the exhaust vent. My goal was to create a smooth path for heated air to flow out the exhaust vent rather than stagnate in the fridge compartment. The last step was to place a smooth curve over the thin cardboard baffle Rockwood installed between the lower and upper vents. I didn't do anything to the lower vent, as I wanted the air intake just as free as possible.


I bought a wireless thermometer at Wal-Mart (less than $10) to get an idea of how the fridge was actually doing, and to adjust the propane flow or AC current (what the knobs do) to keep the fridge temp where I wanted.


The difference in heat flow out the exhaust vent was significant after the mods. The fridge pulled down to 32 degrees from 67 (ambient garage) in less than 4 hours. On minimum cool settings, I could not keep the fridge above freezing. Even on 12V (no adjustment) the fridge actually cooled from 36 to 32 in 2 hours.


Will it do this well camping when it sits in the sun on a warm day? Of course not. But I believe I can get enough cooling to keep it below 40 under any camping conditions. And I can do it without fans using battery.


Just an alternative way to achieve the desired result. And I read about it on the forums. Will post photos tonight.


Fred W
2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time

[KBUZ]

Turbs. Can you give more info on where you purchased everything? Can you give more on how you installed things and if possible more photos? THANK YOU!!!

[TURBS]

I bought everything off of eBay.
My camper is at my sister in laws right now, however I'll be there this weekend and I'll try to get some pics and link you to the items I purchased.



2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"
2016 nights camped "6"

[Flybob]

The gas-absorption refrigerators used in RVs are much less efficient at cooling than your home fridge so their recovery time is slower. In addition, the ability to absorb heat energy introduced when the door is opened is very dependent on the contents. If the fridge is fairly full a considerable amount of heat can be absorbed there by keeping the temp fairly stable. If the fridge is mostly empty, there is little ability to absorb heat. If you are having difficulty keeping the temp stable, try keeping fridge full and open time to a min. A fan in the outside compartment to assist on removing heat from the coils is also a big help.

[Paul GA]

The day mine was giving problems the outside fan did not come on. The day before and day after it did. I can't find the thermostat for the fan. I see it on the wiring schematic but I can't see it.

Also, wonder if the plastic shelf covers and fin cover is making things worse.

[TURBS]

Originally Posted by Paul GA

The day mine was giving problems the outside fan did not come on. The day before and day after it did. I can't find the thermostat for the fan. I see it on the wiring schematic but I can't see it.

Also, wonder if the plastic shelf covers and fin cover is making things worse.

Thermostat "snap disc" is up top in the upper cover if you have one.

It's on the far right screwed to one of the cooling fins.

The stock fans are junk I'd look into replacing it with a 120mm ball bearing fan.




2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"
2016 nights camped "6"

[Paul GA]

Do I have to unseal the roof to get access?

[TURBS]

Originally Posted by Paul GA

Do I have to unseal the roof to get access?

If you have a rooftop vent you won't be able to acces it from the top.
I was referring to an in slide fridge with both vents in the slide wall.




2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"
2016 nights camped "6"

[Paul GA]

Pull the fridge then right?

[TURBS]

Originally Posted by Paul GA

Pull the fridge then right?

I'd have to say yes,



2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"
2016 nights camped "6"

[Paul GA]

Thank you for all the info Turbs!

[TURBS]

Originally Posted by Paul GA

Thank you for all the info Turbs!

Paul, are going to try and replace your fan? Thermostat?


2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"
2016 nights camped "6"

[Paul GA]

Originally Posted by TURBS

Paul, are going to try and replace your fan? Thermostat?


2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"
2016 nights camped "6"

I would like to see the thermostat... see if there is a better quality one or maybe it's poorly mounted... possibly wire in a manual override switch for it. It should have come on that middle day it was the same Temps inside and outside the camper all three days.