WARNING montana high country 385br

[Ribtip]

I agree with the above. I had a guy at our local rec club do some stuff to my air ducts with some tape and blocking off the last vent and such. Not sure what he did but man it made a huge difference in air flow

[Bob Landry]

In spite of what the dealer and others say, the OP's AC is not functioning correctly. Actual, the AC is fine and the issue is with the ducting. 41 degree supply air is way too cold and indicates an air restriction somewhere. R410a units should have mid to upper 50's air temp. It can be anything from dirty filters to a collapsed duct or one where the taping has broken loose.
Spaces not getting air either have duct work that has collapsed or come loose or the ducts and supply grills are not properly taped and you are blowing cold air into the ceiling. This a recurring problem with Keystone. They just don't seem to get it right on air conditioning.
I ran an Outback 277RL for 10 years in the Texas heat and stayed quite comfortable.

[Jorick]

I have a 368MBI with one AC in the bedroom and one AC for the rest of the trailer. The living room AC is inadequate since the space is so large. I live in Mesa, Arizona (115+ degrees in the summer) so I need decent cooling. So I went to Walmart and bought the biggest fan they have (Wind Tunnel) and placed it in the bedroom doorway aiming toward the living room. This moves some of the cold air out of the bedroom into the living room to help out that AC. I keep the thermostat at 80 since it's so dry, and I have no problem keeping the trailer cool even at the hottest temperatures outside. Oh, yeah, I also covered all of the windows with Styrofoam sheets.

[Whitewolf]

When we bought our HC, it had 1 A/C. The one in the main living area. In 2016 my wife needed to spend the summer in southern Missouri to be near her parents who were just admitted to a nursing home.

That A/C burned out. When we had it replaced, I also had a second one(13,500BTU) added to the bedroom. She still had to place blankets over the window blinds to help keep the heat out.

This A/C combination has worked pretty good as long as we stayed in the U.P. or northern climates where we didn't need to cover the windows.

A couple of years ago I went thru the system and made sure the intake and exhaust sides of the A/C were separated and sealed. I also found a break in the ductwork in the ceiling that I was able to access and repair by removing the galley ceiling exhaust fan.

I also discovered the ceiling vents were sticking up into the ductwork by an inch. The ducting is only 2" tall to begin with. I cut the vents down to flush with the bottom of the ductwork to eliminate restrictions.

We are now in South Dakota working our way back home to the U.P. Since we left at the end of July it's been in the high 80's to mid 90's everyday. I close the vent in the bedroom and almost close the one in the bathroom. And we keep the bedroom door open and the bathroom door closed

And we are roasting.

I believe a lot of the problem is having single pane windows thru out. I just used my laser temp gun to take some readings.

First, outside temp is 88 with an 18 mph wind, gusting to 27.
Intake - 78
Exhaust - 64
Inside temp from an inside wall - 79

Ceiling - 82
Wall opposite sun - 83.5
Wall in sun - 86

Slide out ceiling - 88.5 (we have slide toppers)
Slide out wall - 85
Window blind - 88

We are starting to look at new units due to this little girl starting to show her age. We will be looking for something with 3 A/C's and double pane windows.

[wiredgeorge]

The single pane windows let tons of UV through and can get roasting hot. I added very dark tint (I think it was 5 or 15 percent; allowing only 5 or 15 percent of the UV through) for my camper windows and it works great. Others buy covers that adhere with velcro or such.

[Chaz55]

I have the same model but its a montana, not a high country. Ive camped in 90 degree temps and had no a/c issues

[LHaven]

Originally Posted by Mikendebbie

I developed a habit decades ago (several RVs ago) for turning the AC on high and setting the thermostat down LOW and just leave it be. I never use the auto setting. We just let it blow and if it gets cold - that’s the way we like it.

Best part about that approach is that it's trivial to sleep through a constant fan, but having the AC start up every time it cycles wakes DW up (then prompts her to complain, "You've got that thing set too cold!")

[CaptnJohn]

My daughter bought that very same model new in 2017. Florida direct sun. Two 15K have no problem keeping temps inside at 72 during summer. At night she turns off the bedroom AC and at 7 am the front is down for 3 - 5 hours, them both until 9 - 10PM.
The bedroom was fine, actually got too cold. same with the bath. Took down the bath vent and covered 1/3 with metal tape. Took vent down in bonus room. Collars are way too high, cut that down to about 1" ~ maybe less~ and removed every other louver. All in about 3 hours.
OP bought a HC to save weight, money, or both. Items like hydraulic systems and more are heavy and more expensive. Nothing wrong or bad about the HC. I had one with no problems just as my daughter does now. Current and past Montana needed some tweeking on hvac too.
Where I snowbird 4 months in FL about 60 sites have the rear in sun all day. Many add a material like used on vehicle dashboards