2oldman wrote:
Bionic Man wrote:
I have always heard that the air coming out the vents should be about 20* cooler than ambient indoor temp. .
I've heard that from supposed HVAC technicians, and it's not true in my coach. If the air was only 20° colder it would take days to cool down. Perhaps this is a misunderstanding of what it means that RV air can only do 20° colder.
The air coming out of my vents is roughly 55°. I measured it. You can just put your hand on it and feel how cold it is - or at least it should be if it's working properly.
I think both have missed the correct terminology. The other stated AMBIENT INDOOR Temp and that is a improper way to state it. AMBIENT usually means OUTDOOR air temp. But, the Normal Temp Differential is based on the return or return vent closest to the AC and the closest cold air exhaust. The correct should be 18 to 22 degrees differential. This is NOT written in stone for check out, but a way to gauge operation of your AC for yourself. Both RVP and Dometic require me to submit the differential, but they are really interested in the AMP temp corrected draw of the compressor. In your temp of 55 degrees, then the intake at the return filter will be 73 to 77 degrees. There is NO correlation between outside HEAT temps and what a RV AC will do. By that, I mean you do not use the outside air temp in check out. Granted, outside 105 will make it a lot harder to get the inside cold enough. It all depends on the full BTU capacity of your RV AC system. Doug
