A heat duct exits at the front, between the inner wing and the A-pillar. From here, the hot air is routed through a PAP (paper/aluminium/paper) pipe. From here, the warm air is channelled through a PAP (paper/aluminium/paper) pipe, where it is distributed to outlets located at the corners of the windscreen and in the central grille.
starting with the 8.1968, two additional grilles were added under the windshield for most models. This gave the driver and passenger their own ventilation or hot-air supply.
The splitting of the hose is done with a plastic manifold or hose divider, up to 7.1968 this is a 2-way divider and after that it has three connections. If you have a VW 1200 between the years 8.1968 and 7.1975, you do not have a grille in the trunk lid, but you do have to use the 3-way manifold. You then use only the output in the corner of the windshield and the one for the center grille. The other output must be capped.
Due to the choice of materials at the time and temperature differences, the manifolds become brittle. If you don't touch them, they'll stay in good condition for years, but once disassembled, pieces can come off and replacement is the only right choice.
PAP pipes are twisted onto the manifold, so there's no need to use a hose clamp or any other fastening method, as this can only cause cracks in the manifold.
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