We asked Hymer about this and they think it was a winter pack option for the double floor. It shouldn't have a loose end blowing in the locker but they wouldn't give me a schematic to say where it SHOULD be connected.
I know!Inside the van> the normal hose travels along the seating with 3 ducts- none of which blow much air!!That is your problem.
I think what happens is that it blows any dust in the air (I am the same with any blown heaters) and as it comes from the bed end it has to travel all the way along the van.Because we have to have itblowing fast for so long it really> affects my chest which is why we are looking for alternatives.
The solution is simple: your heating system's ducting is in a mess and
Sounds like the ducting is wrong and you are blowing the heat away. ItWe have the butterfly valves but it is amazing how much heat still comes out of them into the garage.
Thanks for all your suggestions.