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Climate Control Question

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Aaron, Dec 6, 2010.

  1. Aaron

    Aaron Member

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    It was 14 F on the way to work this morning. When I press Auto A/C I noticed air is drawn in from the outside and stays that way even when it is warm inside the car. The recirculation symbol does not come on. This normal? Seems like the car would warm faster if recirculating already warm air.
     
  2. fotomoto

    fotomoto Senior Member

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    Did you also have the front defroster on?
     
  3. Aaron

    Aaron Member

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    No. Just pressed Auto A/C after powering on the car. I also use an engine block heater and full grill block.
     
  4. richard schumacher

    richard schumacher shortbus driver

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    It may have decided on its own to do some defrosting. Is the "defrost" indicator on?

    Of course the system wants to use outside air when defrosting because on a cold day outside air is almost always drier than recirculated air, which is humidified with water from your exhalation. You can override that if you want, but the defrost will not work as well.
     
  5. Aaron

    Aaron Member

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    The defrost indicator never comes on.
     
  6. richard schumacher

    richard schumacher shortbus driver

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    Then I'd guess that the cooling function defaults to outside air when outside is cooler than the set point, to use less energy. It should still be possible to override it.
     
  7. Aaron

    Aaron Member

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    Yes. I can override it. I just thought it would automatically choose recirculate to warm faster/save energy.
     
  8. Jerry

    Jerry Junior Member

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    Modern cars always prefer to get outside air whenever possible. They only use recirc in extreme circumstances. The reason for this this is partly to prevent CO poisoning and partly because recirc air quickly becomes humid and fogs up the windows (which usually don't have any problem getting fogged anyway).
     
  9. BAllanJ

    BAllanJ Active Member

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    Even if it didn't fog up on recirc while you're driving around, the humidity you build up in the car would condense on the windows when it cools off when you park. I hate having to scrape the inside of the windows before I can drive off.
     
  10. Aaron

    Aaron Member

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    That makes sense. It does fog up when in recirculation mode. This car IS smarter than me.
     
  11. jdcollins5

    jdcollins5 Senior Member

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    I noticed the same as you that the Auto setting selects the fresh air mode even in cold weather. As you say, the car is smarter than we are.

    I have learned to just set the desired temp, set it to Auto and let the computer do the rest. It always keeps the cabin nice and comfortable.

    The only time I have to adjust anything is to defrost the windshield every now and then.