Heater flapper box question

[Hawks911]

Now that it's getting cold in the mid-west...

Newbie question: can someone tell me if the heater flapper box louvers should be open or closed to produce heat in my 1978 911SC? Got the heater blower motor working after I rebuilt it (brushes and loose solder brush lead connection), but still not much in the way of heat in the cabin. It's getting to the point where my wife is refusing to ride in the car and it's getting colder in a hurry! Can't find anything in Bentley that says if the louvers should be open or closed to produce heat inside.

Thanks.

Mike

[911K]

The flaps should be closed to produce heat. With the flaps open, the system is discharging the heat to atmosphere and closing them directs it to the interior of the car.

With the system adjusted correctly, it produces serious heat in the car especially on the highway at constant RPM.