Dometic refer R & R

[KyDan]

My dometic DM2852 RBX has never cooled like it should.
This is our 4th RV with LP/AC refer so we know what to expect.
All my previous fridges would cool to 40F in any type weather. It didn't
matter if it was 90 outside and nearly the same inside they would cool
to 40 or less.

This one won't! I've tried everything. I've added 2 computer fans in the top
exhaust vent on the roof. Added the little cpu fans kit inside on the cooling fins AND installed an adjustable thermister in place of the fixed one that
comes standard.
All to no avail.

If I don't run the trailer roof AC and keep it 75 inside the refer won't keep up. If the inside temp is 85+ the refer won't cool below 48-50. If it's 90
inside the refer is gonna be more like 53-55.
BUT if it's 90 outside and 75 inside the refer can do 40F.

This leads me to believe it needs more insulation. In fact the installation
manual says the top and sides are supposed to be insulated.
I'm pretty sure they aren't at present.

I'm going to remove it and glue rigid insulation in the sides and top of the opening.
I'm just looking for advice- how to get it out of there.
Anyone here who's removed a refer or has good links to helpful video
or discussion on how to get it out of the opening please step forward!

I'll also see about using some rigid insulation as a baffle at the top if there isn't one there already.

Thanks!

[KyDan]

Still hoping someone with firsthand experience will give me a hint but
I'm heading out to start "taking things loose"!

Film at 11.....

[DaveandSue]

KyDan,ours is a Norcold. It's also in a slide. It didn't have any insulation on the top. Put a bunch of insulation on the top as there was plenty of room.I also made a deflector and angled it to the vent on the slide.It has two of the big vents.Added a bigger volume fan on the back and it has cured the cooling problem so far.

[KyDan]

The deed is done- testing now. The fridge itself has rigid foam sides but the installation manual says to add insulation to the sides and top.
I just did that. Mine is not in a slide and so it's pretty straight forward.
The fridge box fills the hole all but about 6" in the back where all the external coils are located.
It's a straight shot from the bottom to the top and right out the roof vent.
I can't imagine where any baffle would go or how it would help so I just
went with insulating sides and top.

I have 2 computer fans laying on the screen at the very top vent that help pull out some heat. They made a marginal improvement but not enough.
Fingers firmly crossed that this (added insulation) will make it all better. IF not this then I don't
know what other than to think I may have a marginal cooling unit and replacement isn't off the table.

I found videos online about R & R but none like mine. Once I figured how
to get the top trim off the removal wasn't hard. 4 screws inside- two on top and two on the bottom and two outside on the ends of the "runners" that
are made onto the bottom of the unit.

I'll know more in 24 hours.

[KyDan]

Here are before and after photos. I had room for
about 2" thick insulation on the left side and maybe 3" on the
top and right sides.
As I said the refer itself has rigid foam on the outside but still calls for
the opening to be insulated as well.
When I mentioned this to my service writer he scoffed and said they
have plenty of insulation on the refer and don't need more.
Apparently he's never read the installation manual...

I sure hope this makes a difference.
I really like my beer COLD!

[DaveandSue]

Hope it works for you. I've never had problems with cooing on one that had the roof vent. Mine has to of the vents on the slide wall. The angle peice that I put in goes over to the top of the fridge to the vent.

[ependydad]

Thanks for the great pictures, Dan. I'm looking forward to seeing your results.

How are you measuring the fridge's temperature?

[KyDan]

For a quick peek I leave a little pocket type dial analog thermometer in there.
Similar to this one http://tinyurl.com/y9fx5sd9
For a real test I have a digital instant read thermometer that I'll stick in
my freshly opened beer!

Right now I'm loosing hope.
It's been on for nearly 5 hours and the freezer feels really cold but the
fresh food compartment is only 70.
I've never had a RV refer that wasn't pretty cold throughout in 5-6 hours.

I'll see what it's doing in the morning.
If it's not 40 or less I'm gonna have to start looking at replacing the cooling unit.

[KyDan]

No joy in Mudville er I mean Louisville.
Freezer is at 18 and fresh food side is 56.

We have a trip planned in a week.
We'll use the fridge if we can and a cooler if we must.
I'll be shopping for a replacement cooling unit when we get back.

Looks like they run about $500 on Ebay after the old unit is returned.
Utube video of the change out looks daunting but doable.
This %$#^&* unit never has worked right. Time to make a change.

[trozfast]

Mine takes about 12 hours to get cold in the bottom. But it gets down to 33 degrees.

[jughrad]

I assume you know about the adjustment slider inside the refrigerator compartment. I went on a dozen trips or so before I knew about it.

[KyDan]

Mine would not go below 40 ever so I got an adjustable thermister and replaced the fixed one. After that I could see low 30s IF the weather was cool.
When it's hot outside this refer won't keep up.

[ProfChuck]

Yes, I had the same trouble with the slider and the instructions said not to touch it. Finally got tired of it not cooling right and started playing around with it. There was extra cable in the back of the fridge so I pushed it through the hole and adjusted the slider raising it up on the fin it was clipped to. Now i get down to 31 degrees when it is left without opening, even on warm days. Food hasn't frozen and has stayed fresh and cold. Couldn't believe it would make that much difference.

[Bnrc73]

You didn't mention if it worked any better on propane than gas. If propane works better, you could be looking at a weak heating element. $40 Amazon part and 10 minute installation. Lots of u-Tube videos on this.

[Broadway Joe]

If your in the market for a replacement check out this firm.

https://www.rvcool.com/

[DouglasReid]

Dan,
How much space is there behind your refer when it is installed? If the gap is too large the air moving upward simply goes around the cooling fins at the top of your refer. You want that air going over and through those fins, so I have two suggestions:

1. use some rigid foam on the wall behind the refer to make the gap no more than 2", 1" would be ideal.

2. Move those fans that are at the top of the space just below the bent to just below the cooling fins so they blow air directly up onto the cooling fins.

If you do these two small things I am betting you will see a marked improvement in your refer's performance.

Good Luck

[KyDan]

Someone wondered if it worked any better on LP. NO it's pretty much
the same on LP or AC.

Taking Doug's advice from the previous post I pulled the unit out into the floor
-again-.
I got the 2 120MM ball bearing computer fans off the roof -from just under
the top cap- and was all ready to attach them to the bottoms of the
cooling fins at the top rear of the refer.
Got out my tape measure and measured the distance from the front flange
of the refer to the back of the fins. EXACTLY 24".
Stuck the tape in the opening to measure from the front wall to the inside
rear of the opening- EXACTLY 24".
Sheesh. They made the cabinet exactly the depth of the refer.
No baffle needed BUT the fins are about 4" and a 120mm computer fan
is about 4 5/8 so the @#$%^& fans won't fit!

A quick look on the interweb shows they make 100MM fans but they
are few and far between. Found some pricey one's on Amazon and ordered
3 with 2 day shipping for a whopping price of $50.
They'll be here Tuesday. As soon as I get my hands on them I'll mount
them to the underside of the cooling fins and slide that sucker back in the
hole.
I'll try to remember to take a photo and post here once I'm done.

BTW just for the heck of it I turned on the roof AC yesterday.
At that time the inside temp of the trailer was 85 and the inside temp
of the refer fresh food area was 50 something. It had been on for 24 hours at that time.
I let the AC run all afternoon and last night set on 75.
This morning I checked the refer and it was 32 inside.
It's --so-- close to working.
Maybe these fans mounted right under the fins will make the difference.

I'll report back in a few days with results.

[DouglasReid]

It sounds to me Dan as if the 24" and 24" is not leaving room for a good convective current to develop and move the air over your cooling fins. I truly believe the fans will solve that issue!

[KyDan]

The new fans arrived Tuesday afternoon about 4pm. I immediately got busy
installing them.
Here's some photos. You can see the difference in size between a standard
cheap 120mm fan and these rather pricey 100mm replacements.

I got them all hooked up and Rita and I pushed and grunted and managed
to get that thing back in the cabinet one more time. It's a really tight fit
on the sides and of course it doesn't scoot very easy once it's started
into the opening.

After everything was hooked up I went up on the roof to check for air flow
and to re-attach the top vent cap.
ONE OF THE FANS ISN'T TURNING!!! @#$%^*
I've got no idea why. I'm positive they are all hooked up. They all turned
freely. I managed to stick a long wire down from the top and spin the
dead fan and it turns freely.
I must just be a DOA fan.
I can feel a breeze coming up and out the top vent with just the 2 smaller fans running but it was supposed to be 3!!!

I can't do anything about it now. When we get back from this Natchez Trace trip I'll notify Amazon that one of the fans is defective. ARGH!!

It was 90 yesterday when I turned the refer back on.
It was a cool night tho. Anyway with NO roof AC running the refer was
32 inside this morning. I'd say it was a partial test because it did get fairly
cool last night. I'll know more after our trip. I'm sure we'll encounter some
warm/hot weather in LA and MS.

Here's some photos...

[trozfast]

I will look in mine. I will be happy as a lark if there is one there.