Ventilation question
 

Hi guys

I dont understand why when the car is in motion and the ventilation levers are both at the most left position and the fan is closed, I feel the air that is coming in from outside through ALL the vents :confused:

Is there some sort of a shutter that should be closed or can be controlled so when I am driving I wont feel the air from outside?

It depends on year = on your year yes there should be. Maybe your vacuum flap actuators don't work - perhaps due to a vacuum leak - or no vacuum.

When in full operation mode do the flaps operate and change the airflow routing?

One vacuum actuator controlls the water valve - it defaults to open with no vacuum and this means hot water to the heater core - if the other main evaporator flap is open you will get some airflow and in this case it will be hot - if other flap valves are open too you'll get hot air to multiple vents... only the defroster vents default to closed.

Alan

So, in my case, the water valve is indeed open so I get hot air from multiple vents also from the defroster vents (the ones that in-charge of the wind shield).

When the flaps are in full operation mode the air goes through the correct vents.

How can I close or check the main evaporator flap so I wont get the hot air into my face?

I have downloaded the full shop manual however I am missing a lot of pages regarding the HVAC system.

does anyone have page 87-104 in the shop
manual for a complete schematic of the vacuum system?

Also, what is the location of the main evaporator flap that allows the air from outside to get into the car?

Read my thread here and go to the end, it will answer how to close that Heater Valve Actuator.

http://forums.pelicanparts.com/porsche-928-technical-forum/493933-heat-through-door-vents.html

I dont have a vacuum test tule so I thought that I will connect a small air compressor that is also used for creating vacuum...However, I am afraid that the vacuum wont be too strong for the test so I was wondering how many BAR should be the vacuum so I wont damage the system?