AC issues/questions for my class "A"

[RJL]

Finished our trip to SW Fla today. It was boiling hot outside, 90+. From about 1230/p-330/p it was almost unbearable inside the MH. Really absurdly hot. We had both roof AC's running, all vents closed, cab fans running. Our dash AC decided to **** out. Turned it on "MAX AC" and the air wasn't coming out of the dashboard vents, it was coming out of the defroster vents. The roof AC didn't seem to work while driving, worked good when we stopped for lunch. Any ideas?

[wa8yxm]

The Max Air issue. First you do not understand what MAX air is.

IF there is a loss of vacuum on the dash HEVAC it defaults to DEFROST because that is the MOST important function. (NOTE this only affects air flow not temp).

SO I'd guess you have a vacuum hose off or broken or the control is broken.

What is the difference between REGULAR air ON HIGH and MAX air?

Your HEVAC has two air intakes. Outside and Inside. Normal air blends both so youget fresh air inside teh RV. MAX air uses only the inside vent so it recirculates.. Now if it's cooler inside than out. Max air makes it cooler still. IF it's cooler OUT than in. DO NOT USE MAX AIR.

Yesterday My A/C worked perfectly it was 72 degrees in the cockpit. of course it was in the 50's out and the knob was set to VENT 🙂

[FloridaRosebud]

RJL wrote:
Thank you all for the help and suggestions. We have to have some type of a vacuum out of the MH while moving. Like I mentioned, when stopped it works great. I will say I haven't shut all ceiling AC vents down but one. All roof vents are closed while travelling. When we return home I'll give it a try next month. As far as the dash air it has been awful since I bought this rig 5 years ago. Never cold. Had it looked at when still under warranty and of course it checked out fine. It did come out of the proper vents though.

Gotta love RVing. Something breaks, every, single, solitary time I take this thing out.

Thanks again

Bob

I have pretty much the same issue with our Engine AC - doesn't get cold enough. Had the compressor and expansion valve changed, system recharged, and nothing changed. I'd say it's cool, not cold. However, like you, we're in FL, and with the temps in the 90's expecting an engine AC unit to drop the temp 40 degrees to an output in the 50's is not reasonable, especially with the amount of cubic feet it needs to cool. So we run our genny and the front roof AC when we're moving. I agree with some of the others - something is pulling your cold air out of the MH while traveling. (FYI - Ford V10 Triton)

Al

[RJL]

Thank you all for the help and suggestions. We have to have some type of a vacuum out of the MH while moving. Like I mentioned, when stopped it works great. I will say I haven't shut all ceiling AC vents down but one. All roof vents are closed while travelling. When we return home I'll give it a try next month. As far as the dash air it has been awful since I bought this rig 5 years ago. Never cold. Had it looked at when still under warranty and of course it checked out fine. It did come out of the proper vents though.

Gotta love RVing. Something breaks, every, single, solitary time I take this thing out.

Thanks again

Bob

[dougrainer]

You dash AC problem is a Vacumm supply problem. It takes engine Vacumm to operate the Dash AC vent controls. ALL VENTS CLOSED. I assume you mean the 14 by 14 roof vents and not the Roof AC vents. Motorhomes have a natural air leakage to outside when in transit. If the motorhome has unusual gaps that will allow the roof AC cold air to be sucked out in transit. When was the last time you checked and cleaned the Roof AC filters? Doug

[Executive45]

If you're going to run the roof A/C, run just the front air. Close all vents except the one right over your head. You could enhance it further with a sprig loaded shower curtain rod behind the seats with a shower curtain. This reduces the area that needs to be cooled. Finally, have your dash ac checked. Sounds like it needs servicing. If the air is coming out the defroster vents you probably have a disconnected line and/or a vacuum leak....Dennis

[rk911]

did you feel air coming out of the AC vents? was it cool/cold?

[RJL]

rk911 wrote:
did you have the generator running? roof AC needs the genny to run while driving.

Yes

[rk911]

did you have the generator running? roof AC needs the genny to run while driving.