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LM A/C Function Question
Posted by: Wagon Master ()
Date: May 16, 2019 01:19PM

Got my Stock except, for Sansen compressor, 66 A/C system charged and operating in my 69 vert. It has the stock flapper on the blower housing to select cowl or cabin intake air. Not having a 65-67 owners manual, what is the designed function of this flapper? Seem like it would blower colder using already dried, cooled, cabin air but some modern cars say the system is more efficient on cowl/outside air. What say you? Thanks folks.

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Re: LM A/C Function Question
Posted by: joelsplace ()
Date: May 16, 2019 01:23PM

All cars will cool better recirculating the air unless they have a serious design flaw in the system. Cooler drier air is easier to make cooler.

Joel
Northlake, TX
5 Ultravans, Lost count at 100 Corvairs...

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Re: LM A/C Function Question
Posted by: 66vairman ()
Date: May 16, 2019 02:04PM

PM sent

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Re: LM A/C Function Question
Posted by: rnch ()
Date: May 16, 2019 02:17PM

Wagon Master Wrote:
-------------------------------------------------------
> Got my Stock except, for Sansen compressor, 66 A/C system charged and operating in my 69 vert. It has the stock flapper on the blower housing to select cowl or cabin intake air. Not having a 65-67 owners manual, what is the designed function of this flapper? Seem like it would blower colder using already dried, cooled, cabin air but some modern cars say the system is more efficient on cowl/outside air. What say you? Thanks folks.



You are correct! Recirculated (inside cabin) air will always be colder, less humid and more comfortable than "fresh" (outside) air.

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Re: LM A/C Function Question
Posted by: jjohnsonjo ()
Date: May 16, 2019 02:33PM

It takes more energy to lower the due point than to drop the temp.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa


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Re: LM A/C Function Question
Posted by: john.jackson ()
Date: May 16, 2019 03:28PM

WagonMaster,

Take a look at the 67 supplement. Factor A/C was not offered in 68 or 69. Yes, you don't have it. Is there an on line copy??

But if I understand your question correctly, the flapper valve lets you select inside or outside air for lower humidity in certain areas of the country.

Sorry to say, it was close to 50 years since I installed A/C in my 69 Monza Coupe.

Way too much to relearn when I install A/C in my 67 coupe. My 69 Convertible 140, 4 speed will remain factory stock. Easy to appreciate in low humidity environments like Southern California.

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Re: LM A/C Function Question
Posted by: Frank DuVal ()
Date: May 16, 2019 06:27PM

Just like modern cars, recirculate and fresh air are the two choices for the HVAC system. On late model Corvair, the lever marked AIR is pressed down for fresh air. Lever up is recirculate.

In most any vehicle, run fresh air until the system can not accomplish what you need in temperature. Then switch to recirculate. This will keep the windows defrosted better in the winter and flush out whatever is in the cabin, like carbon monoxide!

Now, the Corvair heater does not operate through the AC ducts, it is always sucking fresh air into the heat/ defrost system.

Now, if you are following a hog truck or sitting next to a smoker in traffic, run the recirculate for better cabin smell....grinning smiley Unless you had burritos for lunchthumbs up

Frank DuVal

Fredericksburg, VA

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Re: LM A/C Function Question
Posted by: john.jackson ()
Date: May 16, 2019 09:54PM

Frank DuVal Wrote:
------------------------------------------------------
>
> Now, if you are following a hog truck or sitting next to a smoker in traffic, run the recirculate for better cabin smell....grinning smiley Unless you had burritos for lunchthumbs up


Very Good!

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Re: LM A/C Function Question
Posted by: Timothy Shortle ()
Date: May 16, 2019 10:56PM

I have also noticed the blower is quieter/less volume coming thru the vents when you allow outside air into the cabin.

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Re: LM A/C Function Question
Posted by: Phil Dally ()
Date: May 17, 2019 12:06AM

Holding my breath watching this thread.

Lots to learn in the Corvair A/C world.

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Re: LM A/C Function Question
Posted by: 67 airvair ()
Date: May 17, 2019 03:10AM

That's why the Air 'Vair Group exists. We're a self-help group who meet at every convention for a mega-tech-session, and go about helping one another solve our problems and concerns. I feel that the group actually does the membership a great service by having a set annual meeting. Come join us, as I feel that knowledge is best shared, and if I can share my knowledge with others, then I've made life better for those people. I can't make any better use of what I know than that.grinning smiley

-Mark

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Re: LM A/C Function Question
Posted by: john.jackson ()
Date: May 17, 2019 03:38AM

Phil,

State your questions. Lots of answers here. Most of them really good. As you know.

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Re: LM A/C Function Question
Posted by: joelsplace ()
Date: May 17, 2019 04:58AM

Timothy, I believe that is because on fresh air it is attempting to pressurize the cabin with no vent.

Joel
Northlake, TX
5 Ultravans, Lost count at 100 Corvairs...

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Re: LM A/C Function Question
Posted by: Wagon Master ()
Date: May 17, 2019 05:33AM

joelsplace Wrote:
-------------------------------------------------------
> Timothy, I believe that is because on fresh air it is attempting to pressurize the cabin with no vent.


Where does this system open a "vent" from? I was under the impression all you could change was blower intake air source, temperature (how often the compressor cycles) and blower speed.

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Re: LM A/C Function Question
Posted by: Phil Dally ()
Date: May 17, 2019 06:26AM

Wagon's questions will do for the moment...thanks to all.

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Re: LM A/C Function Question
Posted by: rnch ()
Date: May 17, 2019 07:19AM

67 airvair Wrote:
-------------------------------------------------------
> That's why the Air 'Vair Group exists. We're a self-help group who meet at every convention for a mega-tech-session, and go about helping one another solve our problems and concerns. I feel that the group actually does the membership a great service by having a set annual meeting. Come join us, as I feel that knowledge is best shared, and if I can share my knowledge with others, then I've made life better for those people. I can't make any better use of what I know than that.grinning smiley
>
> -Mark



Mark, how 'bout a link to the Air Vair group; for the "computer challenged" members here?

I'd like to join up.

Tks!

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Re: LM A/C Function Question
Posted by: Frank DuVal ()
Date: May 17, 2019 09:45AM

The vent is a large hole through the fresh air cowl in front of the windshield.

Frank DuVal

Fredericksburg, VA

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Re: LM A/C Function Question
Posted by: Phil Dally ()
Date: May 17, 2019 02:23PM

Went out in Gem to pick up Friday lunch pizza for everybody.

Previously had cool and air levers both pushed full down.

Moved air lever to up position...what a difference!!

Too cold had to slow the fan speed down a notch.

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Re: LM A/C Function Question
Posted by: 66vairman ()
Date: May 17, 2019 04:05PM

joelsplace Wrote:
-------------------------------------------------------
> Timothy, I believe that is because on fresh air it is attempting to pressurize the cabin with no vent.

That does make some difference, but part of the reason is the cowl to blower hole (fresh air) is smaller than the inside bulkhead hole to the blower - well usually. Note Fisher Body did a very crude job of cutting the body holes for A/C based on my four door. I used the GM diagrams from Clark's to cut the holes on my convertible, and clean up the four door holes.

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