Car AC/Heater systems

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wrote:

No, fresh air is standard - and MAX AC does nothing to the fan speed - or at least it didn't when I worked on Toyotas and doesn't on any of the cars I currently am aquainted with. ALL Max AC did was put the system into recirculate mode.

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On Thursday, February 25, 2016 at 4:57:42 PM UTC-5, snipped-for-privacy@snyder.on.ca wrote:

I don't recall which cars it happens/happened in, but hitting the Max AC button without a doubt increased the fan speed. I've never had a Toyota, so maybe they do something different.
It's too cold to go test the Honda Element right now. The Taurus and Civic are away at school. The Gallant has been parted out, so there's no testing that one.

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On Thu, 25 Feb 2016 19:55:48 -0800 (PST), DerbyDad03

The fan sound changes because it is sucking air from inside the car instead of outside the car - Ford works the same way - no effect on fan speed when switched to MAX AC - on SOME fords the water flow through the heater core is shut off on MAX AC - on others it is not. Many vehicles have no hot water control valve.

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On Thursday, February 25, 2016 at 11:26:11 PM UTC-5, snipped-for-privacy@snyder.on.ca wrote:

I'll verify that when I get a chance.

2002, bought in 2012
It was a rust bucket, but we never had any real problems with it, and man, was it quick.
It was the rust that killed it. The brake lines started leaking so I sold it to my mechanic who was going to fix it up for use as a winter heater. Once he got into it he realized how badly rusted the frame and strut towers were. There was no saving it.
On Thursday, February 25, 2016 at 11:26:11 PM UTC-5, snipped-for-privacy@snyder.on.ca wrote:

On Thursday, February 25, 2016 at 11:26:11 PM UTC-5, snipped-for-privacy@snyder.on.ca wrote:

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On Thu, 25 Feb 2016 23:26:00 -0500, snipped-for-privacy@snyder.on.ca wrote:

Every GM car I've had MAX is a higher speed on the fan. Not just sound - fan RPM. It's obvious.
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On Fri, 26 Feb 2016 08:05:16 -0600, Vic Smith

Sport - and the fan speed didn't change with Max AC selected. On the Tauris if I do not have automatic climate control turned on, MAX AC soen't change the fan speed eiter. If automatic control is enabled, hitting MAX AC shuts off the automatic control and it is POSSIBLE tha the fan then goes to max. I'll have to remember to check when I get into it next. (I usually use the Ranger - and the "McGiver AC" does not have any fancy controls. It is a standard non-AC truck with an AC Evavorator added to the system, along with an on/off switch.
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On Fri, 26 Feb 2016 08:05:16 -0600, Vic Smith

I've had many GM cars. This myth has been around since the 60's. But it has never been the case. All that happens is that the recirc door moves and the air resistance in the ducts is reduced. Reduced resistance means more air flow AND it means the motor, now having to do a bit less work, spins a bit faster. So there is a bit more airflow and a bit more noise, but not because there is an extra higher fan speed. If you trace the wring diagrams you see that there is no "extra speed" for "max".
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On Thursday, February 25, 2016 at 11:26:11 PM UTC-5, snipped-for-privacy@snyder.on.ca wrote:

I just drove SWMBO's 2003 Element. (Love that thing!)
When set to Max AC there is a definite increase in the force of the air through the vents. The recirc light also turns on.
Here is a picture of the controls:
http://thumbs4.ebaystatic.com/d/l800/pict/281697436916_1.jpg
You will see that Max AC is on when the mode control is turned all the way to the left. I set the control one position to the right of Max AC, which should mean that all of the air is coming from the dash vents. While holding my hand in front of a dash vent, I turned the control to Max AC. The force of the air coming from the vent increased.
This occurred at any fan speed. There was a noticeable increase in the force of the air flow within a second of turning the control to Max AC. Was it increasing the fan speed? I don't know. I was driving and didn't hear any appreciable increase in fan noise, but the change in force was undeniable. Maybe it was redirecting more air through the vents, I don't know, but the forced increased.

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On Fri, 26 Feb 2016 17:55:43 -0800 (PST), DerbyDad03

Instead of sucking the air through the entire air intake system, the fan is grabbing the air directly at the fan housing - so yes, you WILL get more air flow. However, there is no connection between the recirc door and the fan motor control. The louder air sound and increased air flow are completely caused by the reduction in resistance to intake air flow. At least they have been on several hundred vehicles I have not only serviced but installed the air conditioning on (the vast majority of those installations on Toyotas) Technology has changed some over the years - but that control could just as well have come out of a 1972 Corona Mark 2 or an old Hilux..... It is certainly not rocket science.

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On Thu, 25 Feb 2016 23:26:00 -0500, snipped-for-privacy@snyder.on.ca wrote:

I don't think my 2000 Toyota even has a Max setting!
I was right. It doesn't
But when I put it on automatic and I turn the temp up, the fan goes faster. However unless I'm in a hurry to defrost the windshield, I don't care how cold I am, I only want the fan on one of the first two speeds. So I turned Automatic off again

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wrote:

weekend, and the fan speed most definitely does NOT change when set to Max Air.. It does get much louder because you hear the air being drawn into the fan as well as being blown through the vents.
As far as the 2000 Camry and Solara - the 3-knob non - automatic climate control system has a "fresh/recirc" lever. Recirc is "max air". There is also a version with a push-button "recirc" control
The 4- slide control "automatic" HVAC control also has the "fresh/recirc" control.
In 2001 the camry/solara finally got "real" automatic temperature control with digital readout and an actual "automatic" mode. with buttons for fan off, fan speed (up and down) , Auto, mode, and AC, and a round knob that turns to adjust temperature - which when pushed reads outside temperature.. it also has a "fresh-recirc" button.
So - yes your toyota DOES have a "max air" setting whether it is technically a 2000 or a 2001 model.
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On Thursday, February 25, 2016 at 10:56:13 PM UTC-5, DerbyDad03 wrote:

Max AC on BMW X5 switches to recirculate, high blower speed and 65F.
Also, every car I've ever been familiar with, recirculate isn't 100% inside air. It's more like 80% inside air, which seems logical.
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On Thu, 25 Feb 2016 16:57:30 -0500, snipped-for-privacy@snyder.on.ca wrote:

I'm sorry. "Outside" was used twice in your line just above. It's the second "outside" I was asking about. Do you mean inside? I wouldn't post again except Trader called your post nonsense.

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On Friday, February 26, 2016 at 8:45:19 AM UTC-5, Micky wrote:

My "nonsense" comment was directed at Claire's claim that without a setting that brings in outside air air the humidity builds quickly and the car starts to smell. It's like saying that a house is going to be more humid with the AC on and the windows closed. Obviously AC removes moisture, very effectively. And with less outside air, it will typically be even more effective at doing that.
Also, as I said previously, every car that I've been familiar with, it's never been possible to 100% cut off outside air. At most, setting it to recirculate resulted in about 80% inside air, with ~20% still coming from outside, for obvious reasons.
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wrote:

I don't get that jack-ass's emails any more. I'll repeat myself for clarity. Outside (or fresh) air is normal for both heat and AC on the vast majority of automotive heating and air conditioning or climate control systems. Systems with "max ac" settings switch to recirculated air on the "max ac" setting. Some manual systems, at least in years past, had a "fresh/recirc" control that did the same thing.

And this is why ---

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On Fri, 26 Feb 2016 18:59:14 -0500, snipped-for-privacy@snyder.on.ca wrote:

;-)

Thank you.
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On Thursday, February 25, 2016 at 1:20:19 PM UTC-5, snipped-for-privacy@snyder.on.ca wrote:

Why would an AC system that draws in mostly outside air at 90F be more efficient than a system that mostly recirculate inside air at 75F?

Nonsense. The AC removes moisture from the air, just like any AC system, and there is almost always less moisture in the air that's inside the car than outside. I've never had a car that stays wet, windows fogged up, stinks, with the AC set to fresh air or to recirculate.
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On 2/26/2016 7:28 AM, trader_4 wrote:

Given the ability of technology in cars today, they should be able to pull the air where it will heat or cool the fastest and switch to "outside" after for fresh air. I mentioned in another post that my car started with the AC in recirc position. It would cool the extremely hot air in a sitting car rather than exhaust it and cool the outside air. Never understood that.
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On 2/25/2016 8:33 AM, Micky wrote:

That is the way mine works. Set it and forget it. My last cars were relatively new and the CC worked well. Can't speak for all cars on that.

I had some of that in the past. For some reason, they air would recirculate when the car was hot and you wanted to cool it down. If it is 90 outside, 120+ inside in the sun, bring in that 90 degree air and exhaust the 120 stuff. Sure, if I get in the car I put the windows down, but starting it with a remote, I want the cooker air in to expel the overheated air.
Present car is a Genesis and it has a carbon dioxide detector. It always brings in fresh air. If I do set it to recirculate, it will change to fresh air if the CO2 level gets too high where it would make you drowsy.
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On Thursday, February 25, 2016 at 2:43:50 PM UTC-5, Ed Pawlowski wrote:

The cooker air probably smells pretty good too. ;-)

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