a/c clarification - max vs norm
Fleet Owner
Joined: Aug 2005
Posts: 23,666
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From: Easton,Ks
Originally Posted by tomtoc
i figured it'd be a simple answer. i was really just curious what was "better" for most of the components.
MAX w/ fan on 1 or
NORM w/ fan on 2
17 posts later...who knows
MAX w/ fan on 1 or
NORM w/ fan on 2
17 posts later...who knows
It sounds like some of the posters do understand how the A/C system and DC motors work.
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
Originally Posted by jas88
If there is any difference, I bet you would be hard-pressed to measure it.
Watch your high side gauge and run the A/C with the truck pulled down on MAX and then turn it to NOR and watch the pressure go up. And pressure = MPG.
Lead Driver
Joined: Feb 2002
Posts: 7,958
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From: Greater Austin, Texas
OK, let me be clearer - I bet you would be hard-pressed to measure the difference in terms of wear on your truck and mpg.
I disagree with this. The high-side pressure is much more effected by the speed of air flowing over the condensor, or ambient temp, than by what is going on over on the low-side.
Watch your high side gauge and run the A/C with the truck pulled down on MAX and then turn it to NOR and watch the pressure go up.
Elder User
Joined: Jul 2007
Posts: 681
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From: Agawam,MA
subford and dean88 have it right. In other brand vehicles they have a separate vent control called "fresh" and "recirc". MAX is better overall because you're re-cooling the air while "norm" can be much harder on the refrigeration system itself, especially on a very hot and humid day, pulling in that air and cooling it. But they do say in the manuals to start off in NORM because after being closed up the interior can be a lot hotter than the outside. The louder noise on MAX (and "recirc" for those who have it) is because the blower is drawing air from right under the dash.
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Postmaster
Joined: Aug 2004
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From: West Mansfield, Ohio
Ohhh the classic Normal/Max AC arguement. I can't tell you how many people have said "MAX means its using more fuel and blah blah blah..." and then I slap them.
When you put a Ford on MAX A/C, that is just like hopping into a Chevy, hitting the A/C button, and then hitting the Recirculate buttom to get "Max A/C." Ford, of course, Is simpler!
.
The easiest way I found to explain it, is that in Normal mode, it is trying to cool hot air from outside, while MAX takes the already chilled cabin air, and makes it colder. It may not be right, but it's close enough, and people still don't believe you!
When you put a Ford on MAX A/C, that is just like hopping into a Chevy, hitting the A/C button, and then hitting the Recirculate buttom to get "Max A/C." Ford, of course, Is simpler!
.The easiest way I found to explain it, is that in Normal mode, it is trying to cool hot air from outside, while MAX takes the already chilled cabin air, and makes it colder. It may not be right, but it's close enough, and people still don't believe you!
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
Originally Posted by netscaner
Actually NORM should load the blower slightly more because you are pressurizing the cabin.................unless you have too many rust holes.
Lead Driver
Joined: Feb 2003
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From: Oak Harbor, OH
The A/C system is pretty simple in these trucks. There are two baffles in the heater box, one changes the air from over the A/C coils to over the heater core. The other controls the OUTSIDE air intake. When you put the control in the MAX A/C position it closes the OUTSIDE AIR INTAKE and forces the system to recirculate what's already in the cab. The best way to use you're A/C system is to roll the windows down half way and turn it to NORM for the first few minutes. This will force the HOT air out of the cab and the cooler air from outside is less of a strain on the system at this point. Once the air in the cab is noticeably cooler switch it over the MAX setting, which will keep the system from working as hard. The reason it sounds like the blower is working harder is that you now have a small restriction in the intake causing a higher air velocity in the ductwork, AND you're now hearing the intake side of the blower as well as the output.
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Posting Guru
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short answer if i understand correctly:
MAX is easier on components. use NORM to get fresh, cooler air into the cab when the cab is really hot with the windows cracked then switch over to MAX. can we all agree?
thanks again for what i thought was going to be a simple question with a simple answer.
MAX is easier on components. use NORM to get fresh, cooler air into the cab when the cab is really hot with the windows cracked then switch over to MAX. can we all agree?
thanks again for what i thought was going to be a simple question with a simple answer.