Originally Posted by mherte
I haven't been able to find a thread on this version of poor fridge performance but I'm hoping someone's already solved this problem and can offer some suggestions.
Our refrigerator is a Dometic model RM4223. Up until this weekend, the only issue has been learning which settings provided the least freezing and the best cooling for each power source. However, on our latest trip, we had the unfortunate experience of sour milk and melted butter etc.
As usual, we had chilled it down using shore power (120VAC) for at least one night before leaving. We loaded it up lightly as most meals this trip were not prepared in the camper, and ran it on 12VDC over the 400 mile drive to our campsite. When we arrived at the RV park, I switched to propane. Then at breakfast time we found the box to be rather warm and some food spoiled. This despite the fact that the flame was lit and the "chimney" was hot. So I switched back to 120VAC, but it only cooled slightly. Going home running 12VDC did not provide much cooling at all.
Today, I bought a refrigerator thermometer, placed it in the fridge and connected to 120VAC. I set the temp dial on '7' (usually we use '5'). After 8 hrs, the temperature inside was about 70 degrees. The "chimney" was hot.
To sum up, it seems that performance is poor regardless of power source.
Anyone had a similar experience? Ideas to restore proper operation?
See I'm liking my A-frame fridge
to understand what I went through and details of my "fixes".
My experiences were wildly inconsistent fridge performance in all 3 modes. Sometimes it would cool great, sometimes not at all. On longer trips, the plywood dividing the fridge compartment from the sink actually got hot. I realized the hot air from the heat source was not getting out of the camper.
My first step was to insulate the compartment with Reflectix. I curved the Reflectix to guide the hot air out the top vent. In studying the top vent, I realized they were actually part of a Dometic installation kit for the 4223 fridge. The engineer at Dometic who approved or designed those vents should be fired or worse. They make it very difficult for the needed air flow to set up and cool the fridge coils.
Anyway, the insulation and air guides still did not consistently set up the convection flow (cool air in bottom vent, hot air out top vent) the fridge needs to operate correctly. Like you, I got a remote temp gauge to try to figure things out - mine will work in the minivan while towing.
It turned out that installing a computer case fan to blow air out the top vent was the fix. A couple of others led the way in the linked thread. I found a 120mm/12V/0.07A/440CFM/1200RPM ball bearing computer case fan at Best Buy for $10. I tie-wrapped it to the 2 bottom slots in the top grill on the aft side of center.
- on DC (I use DC mode when towing), air flow of the moving A-frame is sufficient, fan is off, and the fridge will easily pull below freezing at highway speeds for more than a couple of hours. I use pit stops with the fan still off to let the fridge warm back up to prevent freezing contents. There is no way to regulate the DC power to the fridge.
- on AC, I use the fan. Normally have to set fridge at 3-4 (7 point scale) to keep it from freezing. Temps are generally good at 32 - 36 degrees, even in 90+ outside temps. I will start initial cool down with dial set at 7, takes 3-4 hours to pull down below 40 from 82 degree summer temps in my garage.
- on propane, I use the fan. Dial is set from 1.5 to 3 (5 point scale) to keep it from freezing.
While the insulation and ducting helps, the fan is the key to getting the necessary air flow going through those pitiful excuses for vents. With the right air flow, the fridge is a great way to keep food.
2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time
last trip - Black Hills, Custer State Park
next trip - Utah 5 National Parks (Capital Reef, Zion, Canyonlands, Bryce Canyon, Arches)