Best Replacement AC Unit For Old Coleman 48203-666 R410a AC Unit
Updated 08/27/2026 | Published 08/21/2026
Question:
I have a coleman model 48203-666 ac unituses r410a if that matters. Are there any units that work as a direct replacement without having to change out the thermostat and other parts? I think this is a 13500 btu. Can I replace it with a 15k btu without swapping all the parts?
asked by: josh h
Expert Reply:
Hey Josh, thanks for reaching out. We do have a replacement AC unit for you, but since your old unit uses R410a refrigerant, you will need to swap out the entire AC system, not just the rooftop unit. Reason being the new R32 refrigerant units are not backwards compatible with R410a equipment. So, you'll need a new rooftop unit, distribution box, controller and thermostat.
That said, you can absolutely replace your 13.5K BTU unit with a 15K, or even an 18K BTU unit. The new 18K btu units use variable speed compressors, so they actually have more cooling capacity, and less amp draw than a traditional 13.5K or 15K unit. So, for replacing your old R410a unit, I recommend the following:
- Mach-C Everest Variable Speed RV Air Conditioner System - 18K Btu - Ducted/Non-Ducted - R32 - White # CM35MR
This is a complete AC system, so you get your rooftop unit, distribution box and wall thermostat. The distribution box will work with both ducted and ductless setups, and the thermostat can control the AC as well as a furnace if you have one. This will be a great upgrade for your camper. It'll make those summer camping trips much more comfortable, all while pulling less power than your old setup.
Where do you camp most, and how hot does it get inside your RV?
(click to enlarge)
Product Page this Question was Asked From
Mach-C Everest Variable Speed RV Air Conditioner System - 18K Btu - Ducted/Non-Ducted - R32 - White
- RV Air Conditioners
- Complete AC System
- Cool Only
- 18000 Btu
- Standard Height
- Single Zone
- Rooftop
- Ducted
- Non-Ducted
- White
- Coleman-Mach
more information >
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