Max Versus Normal A/C

[content22207]

Just got back from running a few errands, burning my ever controversial A/C the whole way. While sitting at a stoplight, I pondered the following: who in their right mind is going to try to cool 100 degree outside air via the "normal" A/C setting? Mine stays on "Max" all the time. You don't try to cool outside air with your household air conditioner (quite the opposite -- you keep the doors and windows closed and recirculate inside air).

Bill Robertson
#5939

[82DMC12]

Normally if your car has been sitting outside baking in the sun all afternoon the interior air is way hotter than the ambient air. Therefore, generally, you set it to normal at first, then switch to max once the interior air is cooler than the exterior air.

That way you are cooling 'cooler' air in the beginning, thus cooling the cabin faster.

Andy

[DMCMW Dave]

I'm curious about the turn "burning" air conditioning that you keep using. Wouldn't that defeat the purpose? :shocked:

The short answer though - people who want "fresh" air in the cabin. I agree though, max works a lot better once the interior is cool.

[Nicholas R]

When the AC is on "Max" the only difference is that it cuts off the flow of coolant through the heater core correct? On normal the coolant still flows through, there just isn't air flowing directly through it.

[Doogie]

On most of my other cars, the "MAX" setting changes the dampers so that the inside cabin air is sent back through the a/c system. Eventually, the inside air is cooler than the outside air, and it cools even more than using the outside air, etc, etc..

Where I live however (Cincinnati) the defroster system is used quite a bit, especially in the mornings on a cool/cold day. On A/C equipped cars, when the DEFROST mode is selected, the A/C system is activated also, to dry out the air that is blowing on the windshield (makes sense, you don't want 'wet' air blowing on the cold windshield causing frost buildup, the very frost you are trying to remove!

However, if you use the "MAX" or "ReCirc" setting when trying to use the defroster, it doesn't work as well. For whatever reason, the moisture never seems to leave the car in this case, it just keeps blowing on the windshield. The best setting in this case, it to use 'outside' air to dry out the windshield.

On my '01 VW New Beetle, if I select the Defrost mode, the "MAX" button pops out so that I can't select defrost and MAX at the same time.

just my .02

Doogie

[DMCMW Dave]

When the AC is on "Max" the only difference is that it cuts off the flow of coolant through the heater core correct? On normal the coolant still flows through, there just isn't air flowing directly through it.

That's the secondary benefit, the main one is that it draws air from inside the car instead of outside.

[Bitsyncmaster]

You don't use MAX if someone ate beans for supper last night.:tongue:

Or if your a smoker you crack the window and switch to norm.

But in the old days they suggested you not keep recirculate on in case you were getting some carbon monoxide into the car. In my daily driver I use norm most of the time.

[DMCMW Dave]

You don't use MAX if someone ate beans for supper last night.:tongue:


Well put. I was trying to think of a delicate way to say that and gave up.

[Lenny]

When you come to DCS you will change your mind MAX during the summer.



You don't use MAX if someone ate beans for supper last night.:tongue:

Or if your a smoker you crack the window and switch to norm.

But in the old days they suggested you not keep recirculate on in case you were getting some carbon monoxide into the car. In my daily driver I use norm most of the time.

[David T]

The difference between MAX and NORM is in MAX the heater valve is closed and the outside intake is closed. You will still pull in *some* outside air. On different cars (not Deloreans) MAX, NORM, RECIRC, etc do not always mean the same thing. On older cars MAX meant outside air, not recirc. Under most conditions MAX is where you want to be except maybe when first getting into the car when it's been sitting in the sun. First run the vent to blow out the hot air and then go to MAX to start cooling.
David Teitelbaum

[Notifier]

I would think you would always want some fresh air coming into the vehicle. Most household systems aren't designed this way, mainly because of cost. You can get an "air to air" heat exchanger installed on your furnace which would bring in outside air while exhausting stale air, but then these cost money! Almost all large commercial buildings with the roof top units have a fresh air intake for bringing in outside air to the building through the duct work.

[Bitsyncmaster]

When you come to DCS you will change your mind MAX during the summer.

MAX defiantly cools much more than NORM. I will run MAX most of the summer in daylight. But when driving at night you don't really need the cabin temp to be at 50 degrees.

[Michael]

Keep in mind, running on recirculate(max) all the time may lead to a very unpleasant mildew odor in the evap. Constantly recirculating the air could also lead to mold growing in the evaporator. My Volvo will only allow the recirculate option to engage for 15 min, then is switches back to outside air(unless you re-engage it).

As a habit, I only run recirculate when I want the extra cooling.

[vwdmc16]

what volvo model is that?

[Michael]

what volvo model is that?

1998 V70 awd turbo. Just bought it about a month ago and I love it.