Refrigerator Question

musicman

Active Member
I have a 2011 BH 3185 RL with a Dometic Refrigerator. We have the single door with ice maker. Our refrigerator today began going up in degrees. It got over 50 degrees and I decided to empty fridge and turn it off. Not sure what happened. What does that sliding thing in the fridge do. I cannot find anything in the manual about that sliding thing. I had the fridge set on "5" because of the heat outside. It started this morning about 42. Fridge has not worked cconsistantly since we brought the unit home a month ago. Any help would be appreciated. Thanks in advance.
 

jmgratz

Original Owners Club Member
The sliding thing is called a thermistor. It regulates the temperature in the refrigerator section. Make sure it is on the fin and you can move it up and and to regulate the temperature.
 

Cimriver

Well-known member
I had the same issue with our Elkridge. Turned out that a piece of insulation had come loose on the top of the refrigerator blocking the vent. The insulation was moved and it works fine now. You might want to take a look and make sure the vent on top is clear.
 

Ray LeTourneau

Senior Member - Past Moderator
Steve, we have the same fridge. Our slidy thing, the thermistor, is located on the fins in the back of the fridge. Our thermistor is positioned on the fifth fin from the far right side and about halfway between top and bottom of the fin. We had the same issues as you did early on and a technician installed a resistor kit that fools the control panel into thinking the fridge needs to cool more. That worked for us. Your fridge is in a slide out. This makes it easier for you to check the cooling fan/fans that are mounted above the coils on the back of your fridge. Remove the top panel outside on the back wall of the slide out. Make sure there are no obstructions to air flow and see if those fans are working. They are controlled by a thermal switch so it must be warm enough for them to work.
Your best bet is to have your dealer look at it so that everything can be documented in case you have issues later on.
 

musicman

Active Member
Thanks for all your suggestions.....Got up this morning and checked the fridge....It was at 37 degress again......This is so strange......I will have dealer look at it when it goes back in for some other minor repairs.....Thanks again.......
 

DougAndJudy

Well-known member
We find that ours climbs 5 to 8 degrees during the day if the outside temps are in the mid 80s and above. It generally cools down overnight. We were told this is a normal action...
 

Ray LeTourneau

Senior Member - Past Moderator
I should have added, being a "small" unit, it doesn't take too many door opening & closings in a short time frame to raise the temperature.
 
Update on dometic refrigerator.....took rv in the dealer......fridge is getting 12 v power.....fans are all working.....freezer has always worked properly but fridge is still not getting cold enough.......possible problem is a blockage between freezer and fridge.....calling dometic on Tuesday after long weekend.....Should have an answer then....I will keep everyone updated with progress......
 

musicman

Active Member
well fridge is still getting warm throughout the day......up to 58 today......started at 37 this morning......something is definitely wrong....freezer is working great.....calling Dometic Tuesday.....
 

jmgratz

Original Owners Club Member
Check to be sure the cooling fan is working in the rear. The hot air must be evacuated from the rear of the fridge, especially if the fridge is on a slide. If it is on the slide the vent holes on the the outside side walls rather than on the roof. So sometimes it is necessary to add an extra fan. Also the fan has a thermostat on it and turns on when the heat buildup activates it. That fan could be defective.
 

Rickhansen

Well-known member
Musicman,
I have to go along with Ray LeTourneau's thoughts, based on my experience and solution with the same problems you are seeing.
Our 3670 has the fridge installed in the kitchen slide, as does your rig. we're on a long-tern site, in Florida, with the Off Door Side of the rig facing South and were seeing daytime refrigerator temps approaching 60 degrees frequently based on outside temps and sun load.

RV refrigerators are absorption cooling units and are far more "finicky" to temperature differentials than compressor designed equipment, like your home fridge. The flow and pressure changes of the refrigerant happen by the introduction of heat either from an electric heating element or from a small flame. That heat along with the heat that is "pumped" out of the inside of the refrigerator have to be released by the finned coil at the top of the refrigerator chase. As that chase gets hotter from all of these sources, efficiency of the unit goes down proportionally.

In Fridges that are not installed on slides, the upper vent is through the roof which provides much more efficient exhaust of the built up heat than side vented intallations. There are documents available on the web, which Dometic describes the considerations for installing their products in slide out rooms. Their fridges are not designed any differently, and these criteria for side vented installations are left to the RV manufacturer to follow.

First, I added about 2" of fiberglass insulation between the top of the slide and top of the refrigerator. Access to this area is through the upper vent on the outside of the slide. This served to keep heat from being trapped in this area as it is above the upper vent, and it may also keep that heat from warming the freezer.

Second, I installed the resistor kit Ray LeTourneau referenced.

Third, I added another 12VDC muffin fan in the chase to improve cooling airflow. This was difficult as the fan is in the chase midway between the upper and lower vents. I also replaced the fan temperature switch located on the cooling fins in the top of the chase to bring the fans on at a lower temperature. These fans run much more than previously, which might be a concern if you camp on battery power only for long periods.

Fourth, I added a 12VDC muffin fan inside the refrigerator on the cooling fins add some efficiency and to keep the temperature inside the fridge more even.

Our fridge maintains 37 degrees on the highest setting now regardless of the outside temperature and sun loads. The only trade off is that with the humidity here in Florida, I defrost nearly every week as I enjoy an ice-cold beverage.

I can't say that my mods are are fully "factory approved" and may have warranty implications as well, but they have worked for us.
 

jmgratz

Original Owners Club Member
Musicman,

Fourth, I added a 12VDC muffin fan inside the refrigerator on the cooling fins add some efficiency and to keep the temperature inside the fridge more even.

Our fridge maintains 37 degrees on the highest setting now regardless of the outside temperature and sun loads. The only trade off is that with the humidity here in Florida, I defrost nearly every week as I enjoy an ice-cold beverage.

I can't say that my mods are are fully "factory approved" and may have warranty implications as well, but they have worked for us.
As I was reading your post Rick, I thought, "I wonder if that fan on the fins is helping keep the frost down?" Then I read the next sentence.:( You defrost often. We get about 3 weeks between defrosts. I called Dometic about the frosty issue and also had a local authorized tech give me copies of his Dometic manuals sectoin on methods to reduce frost. None of them worked. I guess it's the nature of the beast. Strange though that I have talked to owners that full time and they very seldom have to defrost. I'm puzzled.
 

jmgratz

Original Owners Club Member
Rick and Jan it sounds like you found the solution. Everything I have read and heard about this problem indicates your solution is correct.
 

jmgratz

Original Owners Club Member
Ray you can check the position of the climate switches and one is for high humidity area. That will help.
 

wdk450

Well-known member
Gang:
For most of us Heartlanders the refrig is mounted in a slide, and thus can not have the classic "chimney flue draft" airflow across the cooling fins that the standard-mount refrig's have.
I found a good internet page on RV refrigerator venting here: http://www.rvmobile.com/Tech/Trouble/vent.htm At the bottom of the page are diagrams of good and bad slide installations of RV refrigerators. Blocking off the empty space above the refrig is a primary concern, along with establishing tight air baffles at the 2 cooling fin areas (refrig and freezer).
 
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Rickhansen

Well-known member
Ray,
The fan on the fins helps to minimize frost build-up, but only right where the fan sits. My bet is that since the moisture content is the same it just forms elsewhere (must be one of Murphy's laws) on the fins. In Florida in the summertime, there's no lack of moisture. The colder it gets inside the fridge, the more frost builds up. Without a defrost cycle, like conventional refrigerators, frost just keeps building up.

Jim,
Thanks for the vote of confidence. The Climate (High Humidity) Switch does not prevent frost. It powers some electric heating elements in the sealing faces of the freezer/fridge doors to prevent condensation. That becomes a problem not only of dripping, but mildew on the door seals.

WDK450,
I was looking at fabricating a sheet metal deflector to divert the airflow from the fans directly through the condenser fins, thinking that it would also help push the heat out the upper vent. The fridge worked so well last summer with the changes made, that I haven't taken the time to do so. It's certainly an awkward area to get into to work, and a lack of anchor points.
 

jmgratz

Original Owners Club Member
In the refrigeration course I took they told us to put the fan in the bottom of the fridge as Hot air rises so the idea was to blow the cold air in the bottom to help circulate it more.
 

musicman

Active Member
Here is the update on our refrigerator......Dometic was very nice and said there was a design flaw.....all the heat was escaping through vents and not going over heating coils....so the refrigerator was not getting the proper heat source for cooling. Dometic had rv shop temporarily install baffle to direct all heat over the heating coils. Wow, what a difference. The refrigerator is now a chilly 32 and the freezer is a chilly 0 and it is holding all day long even in the extreme heat. Can't believe the difference. Now the rv shop has to permanently install the baffles and I should be good to go. Heartland needs to notice this design flaw and fix the problem in future models. Easy fix to a very frustrating situation. Thanks Dometic for your help!
 
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