The 4223 is the Dometic fridge also installed in the standard height A-frames. It's quite a bit bigger than the fridge that was in my 2000 Coleman Westlake PUP.
I (and at least a few other A-frame owners) have had issues with inconsistent performance with this fridge. See I'm liking my A-frame fridge
for all the gory details.
My bottom line conclusion is that a combination of poor installation by Forest River, and an incredibly poorly-engineered vent kit from Dometic make fridge performance more miss than hit from what appears to be a great fridge for our pop-ups.
Like others, at times I thought the fridge had quit working in at least one of the modes, but the next time I turned around it was fine.
First clue on my road to discovery was that the aft plywood bulkhead to the fridge compartment was hot (not warm) to the touch on the sink side of the bulkhead. And the air under the sink was hot. The plywood was getting hot enough that I worried about fire.
So I insulated the fridge compartment with Reflectix. I focused on getting the hot air directed to the upper vent, and away from the compartment walls. I also slipped some Reflectix between the coils and the fridge body, and re-aimed the chimney cap to point at the upper vent. My goal was to get the hot air to make the turn down and then up to get through the abominable Dometic vents.
I checked the Dometic installation guide (found on-line for the fridge) and determined that the vents did meet the minimum size and distance apart requirements. The installation guide also pointed out that there should be little-to-no accessible air space around the fridge case, except in the back. So what I did with the Reflectix was correct.
Operation was better, but still hit or miss. I bought a wireless thermometer so I monitor what was really going on. At times performance was so bad on propane, I though I had messed up the chimney when I re-assembled it.
Then a couple of others installed 12V exhaust fans on the upper vent, and had good success. Faced with an August trip to Texas, I decided to try it myself. I tie-wrapped a 120mm 1200 RPM 12V ball bearing computer case fan from Best Buy ($10) to the upper vent, and wired it to a switch. Unbelievable improvement. The fan draws 70 milliamps - 1.7AH per day, which is insignificant. The challenge is turning down the AC or propane enough to keep the fridge from freezing in cooler temps.
I also discovered on the Texas trip that there is enough airflow when towing to turn the fan off. But turning the fan off when parked saw a quick rise to over 40 degrees in the 90+ degree temps. While camping, fan on, AC control was set at "3" and held fridge at 32-36 degrees. Propane had similar results - set at "3", fan on, temps to 29-34 degrees. Fan off, propane on "7", temps rose to 38-44 degrees.
2014 Rockwood A122 A-frame (with 4223 Dometic fridge)
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time