Max Air on Dash Air Condition

RonandWanMI wrote:
Hello, I don't post here much, but i do know your problem.
I've worked with airflow for over 30 years, (now retired)

Most, (if not all) automotive a/c systems use a squirrel cage type of blower for your a/c.

I will try my best to explain my reasoning.
All my cars and RV have a "MAX" A/C setting.

All this does is to shut off the outside intake, and flip a door to suck up fresh air from 'inside' the vehicle.
This makes the motor able to suck more air thru the blower using the same voltage. The motor will be able to suck more air since it is no longer pulling air from who knows how many crooks and turns and how long of plastic or coiled type ductwork.
When you switch to recirc or MAX this will increase the airflow thru the duct work, and it 'will' use more current, but the actual airflow will increase because of the reduction of the inlet restricting to the blades of the blower and it 'will' make the motor increase airflow.
So, while the switch does not change the voltage to the switch, it allows more airflow thru the system by shortening the airflow path to the blower, and you will feel it thru the vents if all installed correctly.
Any questions, just ask. ;)

Yea, I sure do agree with every thing you said. However I can only see a vaccum line and it appears to be attached correctly. But I can not figure out how to see if the door is closing or not. Where in the heck is that door???
Thanks for all the info.

Hello, I don't post here much, but i do know your problem.
I've worked with airflow for over 30 years, (now retired)

Most, (if not all) automotive a/c systems use a squirrel cage type of blower for your a/c.

I will try my best to explain my reasoning.
All my cars and RV have a "MAX" A/C setting.

All this does is to shut off the outside intake, and flip a door to suck up fresh air from 'inside' the vehicle.
This makes the motor able to suck more air thru the blower using the same voltage. The motor will be able to suck more air since it is no longer pulling air from who knows how many crooks and turns and how long of plastic or coiled type ductwork.
When you switch to recirc or MAX this will increase the airflow thru the duct work, and it 'will' use more current, but the actual airflow will increase because of the reduction of the inlet restricting to the blades of the blower and it 'will' make the motor increase airflow.

So, while the switch does not change the voltage to the switch, it allows more airflow thru the system by shortening the airflow path to the blower, and you will feel it thru the vents if all installed correctly.

Any questions, just ask. ;)

They may have knocked the vacuum hose that opens/closes the door off when working on it.
A close inspection should reveal the door and how it operates.

Brian in Michigan wrote:
I think with mine it just sounds that way because of the air being pulled in near the floor, so it sounds like it is working harder.

I do agree that it may just sound that way. However, now, there is no change in the sound or the Air flow.
I got a feeling that the door closing off the outside air is not closing. My trouble is I don't know just where that door is located so I can see if it's closing or not. Also it blew out little bit's of foam rubber after they worked on it last year. The repair man just said after a coach gets so old that rubber just falls apart.
As I said I just have a feeling that that rubber may be stopping the door from closing. Thanks

Max Air on a Class A motorhome does NOT make the fan blow at a higher speed. It DOES close the outside intake door and recirculates the Inside air which will result in colder air output. "Some" Vehicles, it does engage a higher fan speed, but not Class A motorhomes. Doug

robsouth wrote:
Max Air is for recirculating inside air and makes more noise, but I have never known one to blow harder, it just sounds like it is blowing harder.

X-3

Max Air is for recirculating inside air and makes more noise, but I have never known one to blow harder, it just sounds like it is blowing harder. Regular setting cools outside air and makes less noise. I turn on Max Air for few minutes to help cool down quicker, then switch to regular to maintain cool while getting a little fresh air as well.

I think with mine it just sounds that way because of the air being pulled in near the floor, so it sounds like it is working harder.