RM 2852 Refridgerator won't cool, Freezer Fine

Kelly50

Member
Freezer does great job. Refridgerator down below does not cool. It's running on Electric. Sorry new to this. The RV is at our campsite all summer unless we are traveling. So it is always on. It is a 2007 Dometic RM 2852. It has been very hot in the midwest and the fridge temp has got as high as 80 and then back down to 50 at night. Freezer freezes ice solid all the time. I checked the pipes in the back and they are warm everywhere I checked.
 
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jimtoo

Moderator
Hi Kelly50,

Welcome to the Heartland Owners Forum and Family. We have a great bunch of people here with lots of information and all willing to share their knowledge if needed.

You might give us a little more information if you can. Is it running on Propane or elec...what are temps and what fridge and unit do you have. I'm sure some of our other owners will jump in soon.

Enjoy the forum and your new toy.

Jim M
 

dalspot

Well-known member
Kelly, it takes the fridge a lot longer than the freezer to cool down. We find the freezer will freeze things long before the fridge portion gets cold. We were out this past weekend and another told us their fridge works better on gas. You might want to switch over to compare.

We bought 8 ice packs (8"x8") to pack our cooler with and I kept 4 in the freezer this weekend and 4 in the fridge and kept rotating them to help keep things cool. We also had to slide our temp control way up on the fin.

Freezer does great job. Refridgerator down below does not cool. It's running on Electric.

Karen
 

jimtoo

Moderator
Hi Kelly,

Thanks for more info. Since it is plugged in and running all the time, I would check the back side, especially if in a slideout. Some of the fridges have a fan on back side to help move the air across the exterior fins to help dissipate the heat. If yours does not have a fan there, you might try putting a small one to blow up and across the fins to see if it helps.

Keep us informed as to progress.

Jim M
 

Kelly50

Member
Thanks for the advise about the fan. It doesn't have one. I am going up to the campsite and stay overnight. I am going to try it on gas and see if that works. If it does that would seem to eliminate a lot of things.

Thanks
 

jimtoo

Moderator
OK,, check it out,, but to be sure, the fan I am speaking of is outside behind the fridge. You would need to take the vent panel off the outside that is behind the fridge to see it and even then they are hard to see.

Jim M
 

olcoon

Well-known member
Kelly50,
We are also from KC, and had the same problem last summer. Was at Branson the end of July, heat index was around 110+, and ours was giving us big problems. We had to do the same you are doing with the freezer packs. We didn't think we'd have a problem & didn't have enough to keep them in the fridge all the time, just did it during the day, and got by. We had problems with the fridge before this, and it was replaced. When we got back from Branson I took it to 2 different dealers, and they both told me the same thing, it was working as it is supposed to. At the 2nd dealer I had them install the fan in the back of the fridge. So far we haven't had a problem, but this summer we are work camping in Colorado, and don't have the high temps like at home. In case you aren't aware of it, the fridge in your camper has a different system than the one in your sticks & bricks home, so it won't stay as cold in the hot temps. Also I learned at the national rally you can't pack food in it like you would do at home, the cold (semi cool) air needs to circulate in there. Putting the fan in the back will help some, also one of those battery operated fans that you stick in the fridge will also help. They are cheaper at Wally World. From what I understand to install the fan in the back, you have to pull the fridge out into the kitchen. I didn't want to mess with that at the time & had them install it, I think it cost around $200.00.

Where in KC do you live? We are North of the river.
 

wdk450

Well-known member
Kelly:
Since 1 chamber is working OK and one is not, I would ask if you have checked the door gaskets carefully?
Also, if you really want to understand these units, here is a link to the best site I have found on these. Start with the "How it Works" page first. The troubleshooting portion of this website has a LOT of info: http://www.rvmobile.com/tech/Trouble/Index.htm
 

cookie

Administrator
Staff member
One more thing not mentioned is if you have a thermistor on a cooling fin in the refrigerator. Look at the cooling fins in the refer compartment. Check to see if there is a small white piece of plastic with a wire attached to it. If you have one of those it should be attached to the far right fin. Sliding it up on the fin will lower the temp in the refer.

Peace
Dave
 

JohnDar

Prolifically Gabby Member
In the original post, it's stated that it's a 2007 model. When was the last time you had it serviced or inspected? Although northern Michigan isn't the heat capital of the world, our fridge runs continuously from early May to late September with no problems. This is its third season. I do have it checked (per the warranty) annually.
 

Kelly50

Member
We are probably neighbors, 115 terr.

When I got to our campsite last night the fridge said 80. I took both vent covers off for ventilation and started it on gas. After about 2 hours it was down to 55 and by morning it was down to 40. Which is as cold as it ever gets. I then switched it to electric and it held 40. At noon I put the vent covers back on and about an hour or two it was back up to 50, but it's also 102 out. I'm thinking the fan in the back is worth a try. I also checked all the pipes top to bottom and they were all warm like it's flowing good.

Thanks for the reply's
Kelly50
 

wdk450

Well-known member
Kelly:
I think that many of the ammonia adsorbsion refrigerator problems are due to poor installation design causing poor external heat transfer venting. Take a look at this webpage:
http://www.rvmobile.com/tech/Trouble/vent.htm
I am in the middle of making improvements on this and will post about it when I am done, and have temperature data. Right now the trailer is at the repairer for some previously undiscovered external damage. But here is what I did and the results I saw so far.
To start with my refrig is in the kitchen slide, and so uses 2 side vents (not the best way to vent these). Then the top of the refrig is just about even with the top of the upper vent, not good for convection air flow. I do have the pair of factory installed fans. There was a good sized empty space between the top of the refrigerator cabinet and the inside top of the kitchen slide.
My first order of business was to fill the dead air spaces on the top and sides near the back wall with fiberglass insulation batt. I found that the awning rod was an effective stuffing tool. I intend to add fiberglass insulation to the back center inside of the slide exterior to both help with airflow and insulate some from the hot solar heated slide wall. I will probably use spray adhesive on the insulation for this last piece. Others just stuffed into place. Next I wanted to get the full effect of the upper vent although most of it is lower than the top condenser (square finned thingy at the top of the cooling pipes) on the cooling unit. I measured the cooling unit to be 30 inches wide and made a metal baffle that has a small lip to sit on the edge of the condenser fins, then curves down and out to the slide wall below the vent (about 10 inches down). I was able to bend this and manipulate it to slide it in sideways into the vent toward the front of the trailer, than back into place. I secured the top of this baffle to the pipes above the condenser with duct tape. This baffle keeps the air involved in heat exchange near the cooling unit, blown along by the fans, and then out the entire area of the vent, although the warm air has to flow downward at this point, but the fans help with this.
I started the refrig at 5:00 last night, it was about 100 degrees outside, set on coolest, running on gas, with just a few sodas inside. When I came back to take the trailer to the repairer this morning, THE REFRIG TEMPERATURE WAS AT ABOUT 28 DEGREES (too cold).
I hope this helps.
 
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boatto5er

Founding VA Chap Ldr (Ret)
Bill, can you post a picture of the baffle you installed. I think this may be the "magic" missing piece I need.
 

wdk450

Well-known member
Gus:
I don't think a photo of the baffle in place will do it justice, but I will try when i get the rig back from the body repairs. In the meantime, I will see if I can post my working drawings.
OK, my main working drawing is also in the RV, so I drew a new one explaining the entire idea (I hope). This is a side view, the baffle is 30 inches long. It will probably be more readable if you print out a copy of
the image.RV Refrigerator Baffle system 001.jpg

The big idea here is to have airflow JUST along the back of the refrig and over the evaporators and condenser heat exchanging tubes. ANY AIRFLOW THAT DOES NOT FLOW OVER THESE REFRIGERATOR TUBES DOES NOTHING TOWARDS COOLING THE REFRIGERATOR. I SAY THAT INSULATION, BAFFLES OR PLATES COULD BE VERY CLOSE THE BACK OF THESE TUBES AS LONG AS THERE IS A VERTICAL AIRFLOW "CHIMMNEY" PATH UPWARDS TO THE TOP (EXIT) VENT. I DON'T KNOW WHY THE REFRIGERATOR MAKERS DON'T INSTALL A COVER PANEL WITH SIDES OVER THE COOLING TUBES TO DIRECT THE AIRFLOW, WITH EXHAUST FANS AT THE TOP.
 
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Kelly50

Member
Thanks Bill
I will be going back up to the campsite tomorrow to check it out. I don't have any fans yet, but I intend to find some. I think the insulation and baffles are on target as well. I think when I took the vent covers off it provided better air flow, but I also had it on gas. Next I am going to take them off and after I cool it on gas turn on electric and see how long I can hold it.
Thanks again
Kelly
 
Bill, can you post a picture of the baffle you installed. I think this may be the "magic" missing piece I need.

Here are a couple of pics that I took when they installed ours. As you can see in the second pic, the angle of the baffle allows the air to flow over the coils.
Our refer is in the slide with the FL sun directly on it. It was 97 deg earlier and the refer temp maintained 35 deg with normal use. In the morning it is at 33 deg.
This is our second cooling unit in the refer, the first kept the freezer cold but the lower part was at 54 deg., no lower, no higher. Dometic didn't hesitate to fix it.




before baffle.jpg baffle1.jpg baffle2.jpg
 

PSF513

Well-known member
I can tell you from recent experience that my freezer worked like a champ but without opening the refrigerator once during the day, the temp would go from 34 F in the morning to 49 F by supper time and cool down to 34 F overnight. Turns out the sensor that controls our fan failed and the refrierato was not cooling. Dometic made good and replaced the sensor and now the refrigerator stays cooleven on very hot days
 

Kelly50

Member
Thanks Wes

Does anyone have a picture of the fan configuration and hookup points Also the size used and a good place to purchase like Radio Shack for example. My unit has no factory installed fans at all.

Thanks Kelly
 

boatto5er

Founding VA Chap Ldr (Ret)
Thanks for the drawing and pics Bill and Wes. Interestingly, I have a factory installed sheet of metal covering the lower 1/3 of the upper vent. It looks like I can adapt it by bending it over to match what Bill had to install in his. Strange...
 

Kelly50

Member
I have an update on my non cooling RM 2852 refridgerator. I purchased a 12 volt 4inch fan from radio shack with the intentions of installing to the back of my refridgerator. I also purcased some metal to make a baffle directing air to the cooling fins per Bill's advise. What I discovered was there was infact a fan half way down the back of the refridgerator that was not doing anything. I checked power to the thermal switch and had power. Nothing to the other side. I then by-passed the switch and what do you know a nice 4 inch fan started working. I then hooked up an off and on switch and got it going. I then made the baffle Bill talked about and the fridge temp went from 60 to 50 in one hour and by next morning was on 38. It has maintained 38 every sense and is working better then it has since it was new. I ordered the thermal switch today and intend to install it this week.

Thanks Bill and everybody else for the great advise
 
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