windshield defogger -- cool air in warm weather w/o A/C?

There's a thermoswitch in contact with the evaporator fins - just like a
home A/C window unit. When the temp at that switch, which depends on the
temp of the air entering and the temp of the fins themselves, gets below a
certain value, the compressor is disengaged. IOW the compressor cycles on
and off according to the temp of the evaporator fins and air just as it's
entering the evaporator. Climate control systems are a little more
complicated since they also take account of cabin air temp/humidity and
vary the speed of the ventilation fan and the blend of air.

There's a clutch on the drive belt pulley which is engaged when necessary
to turn the compressor on and provide more cooling as needed.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

There's a thermoswitch in contact with the evaporator fins - just like a
home A/C window unit. When the temp at that switch, which depends on the
temp of the air entering and the temp of the fins themselves, gets below a
certain value, the compressor is disengaged. IOW the compressor cycles on
and off according to the temp of the evaporator fins and air just as it's
entering the evaporator. Climate control systems are a little more
complicated since they also take account of cabin air temp/humidity and
vary the speed of the ventilation fan and the blend of air.

There's a clutch on the drive belt pulley which is engaged when necessary
to turn the compressor on and provide more cooling as needed.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

Are we discussing straight A/C or climate control?

 

Are we discussing straight A/C or climate control?

 

If you have auto exhaust gases in your house, why aren't you dead?

Nonsense! The fresh air intakes on my 2003 Accord and every other car
I've driven in the past 25 years are located at the base of the
windshield. If you're sucking in exhaust or other pollutants, they're
someone else's, not yours, so you can zoom along the interstate in Fresh
Air mode and not draw in your own exhaust. I have routinely used recirc
mode when going through tunnels, e.g., Holland & Lincoln, for years.
Avoids sucking in the exhaust & other pollutants in the tunnels. Back to
Fresh Air mode when I pop out the other side, of course.

Japanese law may require a recirc button, but other cars I've driven,
including US makes, have also had them. If you're claiming only Japanese
cars have a recirc mode, better document it.

I refer you to pg. 113 in the 2003 Accord owner's manual, which
describes what happens when you push the Max A/C button:

"The system automatically turns on the A/C and switches to Recirculation
mode."

Hmmm, I guess Honda screwed up big time here. You might want to offer
your services to Honda design so they can get it right the next time.

Actually, Honda seems to contradict itself on pg. 116, where it
recommends initially cooling a very hot car with the windows open &
fresh air mode. It further recommends recirc when the outside air is
humid and fresh air when the outside air is dry. I refer you to pg. 115
which states:

"It is better to leave the system in Fresh Air mode under almost all
conditions. ... Switch to Recirculation mode you are driving smoky or
dusty conditions, then switch back to Fresh Air when the condition clears."

There's no way that can be interpreted as recommending recirc mode most
of the time, as you stated in your original post.

Still, the Max A/C mode sets the A/C to recirc mode, so...

Did you miss or are you ignoring the part about opening windows? They're
a major source of fresh air.

I was talking about *after* the initial cool down period, when you
recommend recirc and Honda recommends fresh air. My point is that
there's not a whole lot of fresh air coming in in fresh air mode with
all windows closed, which means a relatively small incremental load on
the A/C when compared to recirc mode. It's not like having the windows open.

Anyway, re: the OP's question, pg. 117 describes how the A/C is switched
on when defrost mode is selected, with a note that the indicator above
the A/C button stays off.

 

If you have auto exhaust gases in your house, why aren't you dead?

Nonsense! The fresh air intakes on my 2003 Accord and every other car
I've driven in the past 25 years are located at the base of the
windshield. If you're sucking in exhaust or other pollutants, they're
someone else's, not yours, so you can zoom along the interstate in Fresh
Air mode and not draw in your own exhaust. I have routinely used recirc
mode when going through tunnels, e.g., Holland & Lincoln, for years.
Avoids sucking in the exhaust & other pollutants in the tunnels. Back to
Fresh Air mode when I pop out the other side, of course.

Japanese law may require a recirc button, but other cars I've driven,
including US makes, have also had them. If you're claiming only Japanese
cars have a recirc mode, better document it.

I refer you to pg. 113 in the 2003 Accord owner's manual, which
describes what happens when you push the Max A/C button:

"The system automatically turns on the A/C and switches to Recirculation
mode."

Hmmm, I guess Honda screwed up big time here. You might want to offer
your services to Honda design so they can get it right the next time.

Actually, Honda seems to contradict itself on pg. 116, where it
recommends initially cooling a very hot car with the windows open &
fresh air mode. It further recommends recirc when the outside air is
humid and fresh air when the outside air is dry. I refer you to pg. 115
which states:

"It is better to leave the system in Fresh Air mode under almost all
conditions. ... Switch to Recirculation mode you are driving smoky or
dusty conditions, then switch back to Fresh Air when the condition clears."

There's no way that can be interpreted as recommending recirc mode most
of the time, as you stated in your original post.

Still, the Max A/C mode sets the A/C to recirc mode, so...

Did you miss or are you ignoring the part about opening windows? They're
a major source of fresh air.

I was talking about *after* the initial cool down period, when you
recommend recirc and Honda recommends fresh air. My point is that
there's not a whole lot of fresh air coming in in fresh air mode with
all windows closed, which means a relatively small incremental load on
the A/C when compared to recirc mode. It's not like having the windows open.

Anyway, re: the OP's question, pg. 117 describes how the A/C is switched
on when defrost mode is selected, with a note that the indicator above
the A/C button stays off.

 

It must be Toyota, because I've read the same procedure before,
too...more than once. The logic that I think is used in this procedure
is you're cooling a smaller portion of air by using recirc., so the
cooling process will occur more quickly in this mode. The manual also
says to crack windows to dump the cabin's hot air.

Now that I've read this thread, I totally get what you mean. Very
enlightening, educating thread. All of these, years, I've been doing it
wrong.

Funny, I've owned Toyota's since '85, and just recently have said I
eventually wanted to get away from the brand. I drive a Lexus now, and
it's a wonderful car, but I can't say it's perfect. It's got Toyota
quirks just like... a Toyota. Now I read their advice on this subject is
bassackwards.
I had this gut feeling I needed to try another brand's logic that gets
built into a car.

You know who's got it goin' on these days? Nissan. Every_single_one of
their new designs is a work of art. Awesome line up of vehicles now.

 

If you have auto exhaust gases in your house, why aren't you dead? [/QUOTE]

Because the concentration isn't high enough. Nonetheless, city and
suburb dwellers who have cars and trucks driving around their houses
have exhaust pollution inside their houses.

That wasn't what I was talking about. In Japan, where conditions are
very crowded, it's actually law that the cars be built with a separate
recirculate button--for when you're following a stinky car and don't
want to smell the gas. Check it out. Really. It's law over there.

I've seen one or two, but usually they tie the recirculate directly to
the A/C and call it "Max AC" or something similar. American designed
cars usually don't have the recirc button as a standalone piece, giving
the driver the ability simply to shut out the outside world for a bit.
Japanese designed cars ALL have that, because in Japan it's required by
law.

The American mindset with regard to recirculate is goofy, in my opinion.
I want independent choice at any time for where the air is coming from,
where it's going to, and how much--if any--dehumidifying is happening.
Japanese cars ALL give such independent control. Ford Taurus?
Mainstream American car, but no such luck.

yeah, in 2003 Honda finally bows to the American car design of calling
something "Max AC". But all it does is turn the air on and activate
recirculate. Shoot, American cars have had max AC for years and years.
But with Japanese cars, the user can hit that recirculate button any
time he wants for any reason. With American cars, the only time air is
recirculated is with the max AC function engaged. Sorry, too limiting.
I want total control of the system, something the American cars don't
offer.

Ooooo, isn't that amazing. Honda says to hit that INDEPENDENT recirc
button when it's humid outside. Why? Because the A/C is really a
dehumidfier first, using the coolant to extract moisture from the air.
If the outside air is horribly humid, your A/C has to work harder and
won't be as effective. So, hit recirc.

Or when there's pollution and you don't want to smell it--hit the
INDEPENDENT recirc button. The one that American cars by and large
don't have.

Right. And you use the blower fan to force outside (cooler) air in,
which forces the inside (much hotter) air out the open windows. So,
start out in fresh air mode. (Why you'd hit recirculate when the goal
is to blow the inside air out, I don't know. Recirculate simply blows
the horribly hot inside air around inside the cabin...)

Then, when you've gotten the inside of the car in equilibrium with the
outside environment, hit that recirc button. Your A/C won't have to
work so hard, because it will be working with less humid and cooler air.
You'll also be able to turn the fan down, thanks to the cooler and drier
air, which means less noise.

Except when Honda doesn't recommend fresh air, as you quoted above.

And in fact, since a little outside air is always getting in anyway,
it's' no big deal simply to keep it in recirculate.

Unless it's very humid, in which case you want to use recirculate--as
Honda says--to lessen the load on the dehumidifying A/C system.

 

If you have auto exhaust gases in your house, why aren't you dead? [/QUOTE]

Because the concentration isn't high enough. Nonetheless, city and
suburb dwellers who have cars and trucks driving around their houses
have exhaust pollution inside their houses.

That wasn't what I was talking about. In Japan, where conditions are
very crowded, it's actually law that the cars be built with a separate
recirculate button--for when you're following a stinky car and don't
want to smell the gas. Check it out. Really. It's law over there.

I've seen one or two, but usually they tie the recirculate directly to
the A/C and call it "Max AC" or something similar. American designed
cars usually don't have the recirc button as a standalone piece, giving
the driver the ability simply to shut out the outside world for a bit.
Japanese designed cars ALL have that, because in Japan it's required by
law.

The American mindset with regard to recirculate is goofy, in my opinion.
I want independent choice at any time for where the air is coming from,
where it's going to, and how much--if any--dehumidifying is happening.
Japanese cars ALL give such independent control. Ford Taurus?
Mainstream American car, but no such luck.

yeah, in 2003 Honda finally bows to the American car design of calling
something "Max AC". But all it does is turn the air on and activate
recirculate. Shoot, American cars have had max AC for years and years.
But with Japanese cars, the user can hit that recirculate button any
time he wants for any reason. With American cars, the only time air is
recirculated is with the max AC function engaged. Sorry, too limiting.
I want total control of the system, something the American cars don't
offer.

Ooooo, isn't that amazing. Honda says to hit that INDEPENDENT recirc
button when it's humid outside. Why? Because the A/C is really a
dehumidfier first, using the coolant to extract moisture from the air.
If the outside air is horribly humid, your A/C has to work harder and
won't be as effective. So, hit recirc.

Or when there's pollution and you don't want to smell it--hit the
INDEPENDENT recirc button. The one that American cars by and large
don't have.

Right. And you use the blower fan to force outside (cooler) air in,
which forces the inside (much hotter) air out the open windows. So,
start out in fresh air mode. (Why you'd hit recirculate when the goal
is to blow the inside air out, I don't know. Recirculate simply blows
the horribly hot inside air around inside the cabin...)

Then, when you've gotten the inside of the car in equilibrium with the
outside environment, hit that recirc button. Your A/C won't have to
work so hard, because it will be working with less humid and cooler air.
You'll also be able to turn the fan down, thanks to the cooler and drier
air, which means less noise.

Except when Honda doesn't recommend fresh air, as you quoted above.

And in fact, since a little outside air is always getting in anyway,
it's' no big deal simply to keep it in recirculate.

Unless it's very humid, in which case you want to use recirculate--as
Honda says--to lessen the load on the dehumidifying A/C system.

 

That's my usual approach. At the start I'm much more interested in
getting the superheated air out of a hot car than worrying about
cooling. I have the automatic climate control on my 03 Accord and it
always wants to go straight to recirculate when the car is hot. I
always over-ride that.

Frankly, I find the fresh air works better most of the time. The
exception is trying to warm up a car when it's 20 below out. You do
have to switch to fresh air at some point to avoid the windows
fogging. When it's hot, I really don't notice a big improvement with
recirculate, and seldom use it.

BTW, I like the autoclimate control precisely because it allows you to
pick and choose which aspects are automatic. I can over-ride the fresh
air, or which vents are chosen, fan speed, AC etc and the rest stays
in the auto mode (ie, manages to the temp setting).

 

That's my usual approach. At the start I'm much more interested in
getting the superheated air out of a hot car than worrying about
cooling. I have the automatic climate control on my 03 Accord and it
always wants to go straight to recirculate when the car is hot. I
always over-ride that.

Frankly, I find the fresh air works better most of the time. The
exception is trying to warm up a car when it's 20 below out. You do
have to switch to fresh air at some point to avoid the windows
fogging. When it's hot, I really don't notice a big improvement with
recirculate, and seldom use it.

BTW, I like the autoclimate control precisely because it allows you to
pick and choose which aspects are automatic. I can over-ride the fresh
air, or which vents are chosen, fan speed, AC etc and the rest stays
in the auto mode (ie, manages to the temp setting).

 

I haven't owned a Japanese vehicle since my 1997 Lexus but it and
my two previous Lexus' did not have a manual recirc, they ALL had
automatic recirc as part of the system, as do most American
cars. Only the low end American cars like the Escort have the
less expensive manual recirc. Even on recirc some air is drawn
from outside and exhausted, in any event


mike hunt

Because the concentration isn't high enough. Nonetheless, city and
suburb dwellers who have cars and trucks driving around their houses
have exhaust pollution inside their houses.

That wasn't what I was talking about. In Japan, where conditions are
very crowded, it's actually law that the cars be built with a separate
recirculate button--for when you're following a stinky car and don't
want to smell the gas. Check it out. Really. It's law over there.

I've seen one or two, but usually they tie the recirculate directly to
the A/C and call it "Max AC" or something similar. American designed
cars usually don't have the recirc button as a standalone piece, giving
the driver the ability simply to shut out the outside world for a bit.
Japanese designed cars ALL have that, because in Japan it's required by
law.

The American mindset with regard to recirculate is goofy, in my opinion.
I want independent choice at any time for where the air is coming from,
where it's going to, and how much--if any--dehumidifying is happening.
Japanese cars ALL give such independent control. Ford Taurus?
Mainstream American car, but no such luck.

yeah, in 2003 Honda finally bows to the American car design of calling
something "Max AC". But all it does is turn the air on and activate
recirculate. Shoot, American cars have had max AC for years and years.
But with Japanese cars, the user can hit that recirculate button any
time he wants for any reason. With American cars, the only time air is
recirculated is with the max AC function engaged. Sorry, too limiting.
I want total control of the system, something the American cars don't
offer.

Ooooo, isn't that amazing. Honda says to hit that INDEPENDENT recirc
button when it's humid outside. Why? Because the A/C is really a
dehumidfier first, using the coolant to extract moisture from the air.
If the outside air is horribly humid, your A/C has to work harder and
won't be as effective. So, hit recirc.

Or when there's pollution and you don't want to smell it--hit the
INDEPENDENT recirc button. The one that American cars by and large
don't have.

Right. And you use the blower fan to force outside (cooler) air in,
which forces the inside (much hotter) air out the open windows. So,
start out in fresh air mode. (Why you'd hit recirculate when the goal
is to blow the inside air out, I don't know. Recirculate simply blows
the horribly hot inside air around inside the cabin...)

Then, when you've gotten the inside of the car in equilibrium with the
outside environment, hit that recirc button. Your A/C won't have to
work so hard, because it will be working with less humid and cooler air.
You'll also be able to turn the fan down, thanks to the cooler and drier
air, which means less noise.

Except when Honda doesn't recommend fresh air, as you quoted above.

And in fact, since a little outside air is always getting in anyway,
it's' no big deal simply to keep it in recirculate.

Unless it's very humid, in which case you want to use recirculate--as
Honda says--to lessen the load on the dehumidifying A/C system.[/QUOTE]

 

I haven't owned a Japanese vehicle since my 1997 Lexus but it and
my two previous Lexus' did not have a manual recirc, they ALL had
automatic recirc as part of the system, as do most American
cars. Only the low end American cars like the Escort have the
less expensive manual recirc. Even on recirc some air is drawn
from outside and exhausted, in any event


mike hunt

Because the concentration isn't high enough. Nonetheless, city and
suburb dwellers who have cars and trucks driving around their houses
have exhaust pollution inside their houses.

That wasn't what I was talking about. In Japan, where conditions are
very crowded, it's actually law that the cars be built with a separate
recirculate button--for when you're following a stinky car and don't
want to smell the gas. Check it out. Really. It's law over there.

I've seen one or two, but usually they tie the recirculate directly to
the A/C and call it "Max AC" or something similar. American designed
cars usually don't have the recirc button as a standalone piece, giving
the driver the ability simply to shut out the outside world for a bit.
Japanese designed cars ALL have that, because in Japan it's required by
law.

The American mindset with regard to recirculate is goofy, in my opinion.
I want independent choice at any time for where the air is coming from,
where it's going to, and how much--if any--dehumidifying is happening.
Japanese cars ALL give such independent control. Ford Taurus?
Mainstream American car, but no such luck.

yeah, in 2003 Honda finally bows to the American car design of calling
something "Max AC". But all it does is turn the air on and activate
recirculate. Shoot, American cars have had max AC for years and years.
But with Japanese cars, the user can hit that recirculate button any
time he wants for any reason. With American cars, the only time air is
recirculated is with the max AC function engaged. Sorry, too limiting.
I want total control of the system, something the American cars don't
offer.

Ooooo, isn't that amazing. Honda says to hit that INDEPENDENT recirc
button when it's humid outside. Why? Because the A/C is really a
dehumidfier first, using the coolant to extract moisture from the air.
If the outside air is horribly humid, your A/C has to work harder and
won't be as effective. So, hit recirc.

Or when there's pollution and you don't want to smell it--hit the
INDEPENDENT recirc button. The one that American cars by and large
don't have.

Right. And you use the blower fan to force outside (cooler) air in,
which forces the inside (much hotter) air out the open windows. So,
start out in fresh air mode. (Why you'd hit recirculate when the goal
is to blow the inside air out, I don't know. Recirculate simply blows
the horribly hot inside air around inside the cabin...)

Then, when you've gotten the inside of the car in equilibrium with the
outside environment, hit that recirc button. Your A/C won't have to
work so hard, because it will be working with less humid and cooler air.
You'll also be able to turn the fan down, thanks to the cooler and drier
air, which means less noise.

Except when Honda doesn't recommend fresh air, as you quoted above.

And in fact, since a little outside air is always getting in anyway,
it's' no big deal simply to keep it in recirculate.

Unless it's very humid, in which case you want to use recirculate--as
Honda says--to lessen the load on the dehumidifying A/C system.[/QUOTE]

 

they have a "MAX A/C" button- same thing.

 

they have a "MAX A/C" button- same thing.

 

they have a "MAX A/C" button- same thing.[/QUOTE]

no, it's not. MAC A/C turns on the air conditioner--period. I may not
want that. I want control of my systems, including a separate
recirculate button that's not tied to any other system. It just
operates the blend door and closes it. Period. No other system is
touched, and the A/C doesn't come on just because I wanted recirculate
for a moment or two while I get away from the stinky bus.

 

they have a "MAX A/C" button- same thing.[/QUOTE]

no, it's not. MAC A/C turns on the air conditioner--period. I may not
want that. I want control of my systems, including a separate
recirculate button that's not tied to any other system. It just
operates the blend door and closes it. Period. No other system is
touched, and the A/C doesn't come on just because I wanted recirculate
for a moment or two while I get away from the stinky bus.

 

What? You couldn't reach over and push the button off if you didn't want
recirc?

You know, as much as you post in differing car ngs, you should show some
class and clip unnecessary verbage. If someone like me, on webtv, the
scourge of usenet, can do it, what's your excuse?

The answer could lie above in the first portion of my response.