>I'm installing my Propex heater (finally) under the rear seat and have
some
>questions about where to route the combustion inlet pipe. I'm routing the
>outlet pipe to the edge of the passenger-side rear jack flange. The
>instructions that came with the heater say to keep the inlet and outlet
>openings 0.5 meters apart and that the openings should face the same
>direction.

>Why do the openings need to face the same direction?

That's because of the wind (air pressure differences). If the wind blows
into one pipe, the airflow in the heater can be reduced or accelerated.
It could smoothen or just blow out the flame.

>Where is a good place to put the inlet pipe opening?
If you haven't done the installation, route both in- and out-let through
the flour to the bottom of the van like VW did with the Waebasto heaters.
I installed a Truma heater (same like Propex) with a coaxial in-outlet
system. The inlet pipe is covered by the outlet pipe and both are routed
through the same hole in the side panel. The outer cover is made in that
way, that the inlet is below the outlet.
Below the outlet you should add a dripp-off plate. If the exhaust cools
down you get a acid liquid which attacks the paint. If you have a fridge
running on Propane, you should add the dripp-off plate on its exhaust
outlet also.
BE SURE THAT THE OUTLET PIPE DO NOT HAVE A BOW DOWNWARDS WHERE THIS ACID
LIQUID COULD BE COLLECTED.
The outlet pipe have to go straight upwards or downwards!
Helmut
'80 Camper