Exploring the HVAC system in detail (with videos)

[nick88highline]

Now the fourth part in which I go through, in detail, the flow of air through the HVAC box:


View: https://www.youtube.com/watch?v=sJv4m1fw900


This might help to explain some issues, but if not, let me know and I'll focus on those.

 

[Green]

Nick, thank you for your videos!
I asked you this question on YouTube on your Part 3 video as well...Do you find that the pump/actuator functions differently in Auto versus Manual mode? I have the situation where the pump seems to remain open, even in LOW setting, and the air coming out of the rear is as hot as the sun. Are there any sequence of settings that get the actuator to force closure? Any information would be appreciated. Thank you again! Cheers

 

[ADVAW8S]

Now the fourth part in which I go through, in detail, the flow of air through the HVAC box:


View: https://www.youtube.com/watch?v=sJv4m1fw900


This might help to explain some issues, but if not, let me know and I'll focus on those.

Thank you for this, it explains a lot. I will add an observation based on your teaching. I think the reason why the rear gets no heat when on foot, is because the vent for feet blows air to slant portion of driver and passenger footwell. The slant then pushes the air towards the rear passenger. While defrost goes up the window and then heads to back. The other thing I will mention, is I assume the cool open air that does not go over the hot water, is the mixing air. We have the ability to set a temp. I assume the cool air mixes with the hot air and the hot air flap dictates how much hot air is passed into the mixing chamber.

Finally, the missing piece to cabin temp management is the vent closure. I tend to run my cabin on defrost and foot. Then I close the middle vent flaps to eliminate the cool air that gets push to direct face. The side circle vents provide warm air, again pushed to back. In the summer, on real hot days, I run just face and open the side vents. The defrost creates condensation on the front window. I also never have my fan above 2. It's 1 or 2 which I think does a better job of moderating the cabin temp.

 

[Blackwolf]

Thanks Nick, very interesting.