I have seen NO problems with the newer units and MOST have had the R410a for over 3 years. The problem is simple. A lot of newer RV's have multiple slides and THAT increases the square footage of the area to be cooled, plus with the inherent slight leakage of slide seals(slides allow a lot more air to escape). The OP needs to clarify his post. He implies with the way he wrote it that DOMETIC is claiming to be aware of cooling problems with the R410a. Which is NOT true. I am a simple person. 15k or 13.5k of cooling BTU's is THAT. Regardless of what they use to operate the system. Yes, as a dealer, we recommend that a trailer as big as 39 feet have at least 3 AC units. Depending on the floorplan (that number of slides again) having 3 instead of 2 can make the difference in 90 plus heat. Doug
