My S1 OTS was previously dismantled and I do not have details of the positioning of the seals on the air flap. The parts diagram shows the kit of foam seals ( a rectangle surrounded by four narrow strips ), all in the same plane.
When HOT is selected the air flap closes against the air release duct ( Plate no. 55-5 ) with the rectangle seal on the side of the air flap against the duct.
When COLD is selected the air flap is operated against the water radiator ( Plate no. 55-8 ). Where do the remaining four narrow strips fit to seal the air flap in this position?