Why do vents default to outside air?

Just wondering--whenever I use the AC, my Accord keeps defaulting to
outside air (as do most newer vehicles, I've noticed). I drive mostly
in traffic and don't like to breathe exhaust fumes filling the car, so
I'm continually resetting it to recirc. But I'm curious as to why
outside air is the default setting. (?)

2000 Accord v6 sedan

Jeff

 

Honda flipped a coin, maybe?

 

Honda flipped a coin, maybe?

 

Probably the same reason many other car manufactures do, so that can
have that ridiculouly labelled "Max Air" button, which merely changes the
air flow from outside to recirculate, and makes people think they have two
levels of air conditioning power.


Bob

 

Probably the same reason many other car manufactures do, so that can
have that ridiculouly labelled "Max Air" button, which merely changes the
air flow from outside to recirculate, and makes people think they have two
levels of air conditioning power.


Bob

 

The AC uses a "just enough and no more" sort of logic. When it decides it
can't achieve the temperature you asked it for, then it opens the recirc
door. If you have the AC where you select a temperature, set it to 60
degrees (F) and the recirc light will come on immediately (unless the
outside temperature is 40).

You should know that even when you put it in recirc, a small amount of
outside air is still drawn in. This is so you don't pass out from your own
exhaust fumes concentrating in the car.

 

The AC uses a "just enough and no more" sort of logic. When it decides it
can't achieve the temperature you asked it for, then it opens the recirc
door. If you have the AC where you select a temperature, set it to 60
degrees (F) and the recirc light will come on immediately (unless the
outside temperature is 40).

You should know that even when you put it in recirc, a small amount of
outside air is still drawn in. This is so you don't pass out from your own
exhaust fumes concentrating in the car.

 

That's interesting. Perhaps you should have your vehicle's system checked
for a problem. My A/C does nothing, unless I tell (push a button) it to
perform a task.


--
Brian

http://www.cakesbydarlene.ca

http://www.accesswave.ca/~orion

 

That's interesting. Perhaps you should have your vehicle's system checked
for a problem. My A/C does nothing, unless I tell (push a button) it to
perform a task.


--
Brian

http://www.cakesbydarlene.ca

http://www.accesswave.ca/~orion

 

I have 99 Accord, European Model With Automatic AC, when I use it on
Full AUTO , the outside Air vent is closed, which make sense, on
Manual I presume every setting should me manual.
Few months back I was in LA , where I drive Toyota Camry , in which
outside air vent was independent of using AC

 

I have 99 Accord, European Model With Automatic AC, when I use it on
Full AUTO , the outside Air vent is closed, which make sense, on
Manual I presume every setting should me manual.
Few months back I was in LA , where I drive Toyota Camry , in which
outside air vent was independent of using AC

 

I think the OP is talking about auto climate control. The system
utilizes recirc for fast cooling and when it's achieved, changes to
fresh air.

 

Because once the inside air has been dehumidified through the process
of a/c, the a/c will struggle to cool that air again.

recirc works great to cool a steamy car initially, because it is not
only throwing cold air at you, but is taking away the hot inside air.
but once the car has cooled you want to switch back to outside air
(unless a situation like behind a bus, etc., as you mention).

also windshield will fog up in certain conditions when using recirc.

rob

 

Because once the inside air has been dehumidified through the process
of a/c, the a/c will struggle to cool that air again.

recirc works great to cool a steamy car initially, because it is not
only throwing cold air at you, but is taking away the hot inside air.
but once the car has cooled you want to switch back to outside air
(unless a situation like behind a bus, etc., as you mention).

also windshield will fog up in certain conditions when using recirc.

rob

 

"Rob" wrote

This is all backwards to me, unless it's because I live in a hot, dry
climate. When first getting into the car, the temperature inside the car can
be 40 degrees hotter than outside; therefore, here one first needs to use
fresh a/c. Once the interior starts to cool off, *then* switch to
recirculate. The a/c won't have to work so hard, cooling air that is already
temperate, not at inferno-grade.

 

"Rob" wrote

This is all backwards to me, unless it's because I live in a hot, dry
climate. When first getting into the car, the temperature inside the car can
be 40 degrees hotter than outside; therefore, here one first needs to use
fresh a/c. Once the interior starts to cool off, *then* switch to
recirculate. The a/c won't have to work so hard, cooling air that is already
temperate, not at inferno-grade.

 

Might be a function of the climate control temperature setting. Put the
temperature at minimum (60) and see if the recirc light comes on. I have a
2000 Accord V6 and that's what happens.
MLD

 

Might be a function of the climate control temperature setting. Put the
temperature at minimum (60) and see if the recirc light comes on. I have a
2000 Accord V6 and that's what happens.
MLD

 

Right. Backwards. It's easier to make already cool air colder, or to
keep it cool--there's less heat to remove to the cooling coils. Also,
same goes for humidity. If you keep pumping super humid air from outside
into the car, the air won't necessarily get as dry as it would if you
use the recirc setting.

I'd guess it's switching back to outside air for safety reasons--these
newer cars are so airtight that one needs a fresh supply or air to
prevent CO poisoning if there were a problem with your exhaust system,
for example. Or as others have suggested, the climate control could be
doing it based on air temp.

 

Right. Backwards. It's easier to make already cool air colder, or to
keep it cool--there's less heat to remove to the cooling coils. Also,
same goes for humidity. If you keep pumping super humid air from outside
into the car, the air won't necessarily get as dry as it would if you
use the recirc setting.

I'd guess it's switching back to outside air for safety reasons--these
newer cars are so airtight that one needs a fresh supply or air to
prevent CO poisoning if there were a problem with your exhaust system,
for example. Or as others have suggested, the climate control could be
doing it based on air temp.