F-Type ( X152 ) 2014 - Onwards
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  #1  
Old 01-15-2016, 07:46 PM
martybmw's Avatar
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Having small issue when just using the system for outside air, if I have the temp turned down enough when trying just to get outside air the air conditioning comes on but the AC doesn't light up. Then have to keep turning up the temp until the AC stops and outside air comes in. Do I have some preset done incorrectly or is this just the way the system is?
thanks
 
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Old 01-16-2016, 10:23 AM
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I've read it a few times but am not completely clear on what you are asking.

The ventilation sometimes switches to recirculation mode automatically below (and above) certain temperatures. That is because the system knows it couldn't reach your requested temperature when the temperature difference to the outside air is too great. That is all managed by comfort algorithms in the automatic temperature control module (ATCM), and should only happen in automatic mode.

When the AC is activated or not is linked in to the same logic. I've noticed that sometimes when calling for maximum air to the windscreen for demisting on a cold morning wet air (not air conditioned) is often used for the first ten seconds or so and then the AC kicks in, and then it turns off again after a few seconds and wet air hits the screen again.

In previous cars with automatic climate control windscreen air has always gone through the AC first to avoid blowing moist air onto a condensing surface, so I am unsure why that appears to happen differently in the F Type. There is a humidity sensor mounted next to the rear view mirror which as well as testing the actual air humidity also uses the temperature of the windscreen and the incoming air to determine the dew point for condensation to form. I suspect the algorithm is a little too optimistic and the evaporator core temperature is fluctuating too quickly in a cold car.

From reading on TOPIx it seems that the ATCM will always give priority to preventing window condensation forming over any requested comfort ventilation settings possibly including manual settings. That may be why you are seeing the system take back control over the air source. Are you seeing this at temperatures where condensation forms?

Do you have the pollution/air quality sensor fitted to your vehicle? Sometimes I hear my air source switches to recirculation only when I am sitting in heavy traffic. If you suspect that might be it you can disable it on the climate settings screen.

I've attached the overview pages from TOPIx to this post for you to read.
 
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  #3  
Old 01-16-2016, 05:48 PM
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Thanks for such a comprehensive response. Don't have the condensation issue more like when it about 65-70 F and just want outside air that the Air Conditioning kicks on and I have to play with the temp setting to keep the AC form coming on.
thanks
again
Marty
 
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Old 01-18-2016, 01:36 PM
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Have you tried switching off the aircon?
 
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Old 01-18-2016, 02:59 PM
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Originally Posted by F-typical
Have you tried switching off the aircon?
Yes, sir.
 
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