Long time stalker, 1st time writer. We have a 2016 Fuzion 420 with 3 a/c's. We live in northern lower Michigan, and the dealer had two 420's. One with 2 units, the other with 3. Salesperson said she did not see the need for 3, unless you live in Arizona. That sold me, I like it cool. However, the first 1st time we camped with high heat and humidity, the 3 units struggled to keep our camper cool. Prior to this 5er, we had a 1986 35' Jayco 5er, with 1 a/c unit, no duct work, and that baby got cold. When we got back home. I started the investigation, using the knowledge I acquired from this forum, thanks everyone. 1st stop, vent ducts, everything good. Next, bottom cover of center a/c, above loft, awesome location I might add, thanks Keystone. The divider had been blown out of position, so a little aluminum duct tape and good. Well, so so good, that increased the air movement slightly, and I mean slightly. My thermostat is set up as zone heating/cooling, mine has 3 zones. Zone 1 is the living/kitchen area. Zone 2 is the bedroom/bath. Zone 3 is the garage. When I turn on zone 1, to cool just the living area, the center a/c is the only one that comes one, but is connected to the entire duct system, so essentially, I have 1 a/c trying to cool the whole 43' beast. I then taped off the vent in the bedroom and the one in the garage. It made a big difference, and I can actually zone cool by opening up the louvers on the bedroom and garage a/c units, so the air stays out of the vents, and cools the desired area. Sorry for the long post, like I said 1st time, hopefully I'll get better.
