pressure vent on van

Can't help you with the Avan Ken, but my experience with pressure vents in other situations is that unless they are above the line of dust, they are self-defeating.

You can't successfully put filters in them as this reduces the airflow to the point where it doesn't work anyway.

For most gravel road driving they can make a small difference if above the dust cloud, but when in bulldust, forget it.

Cheers

Russ.

sorry meant a van. not avan
do you only open it when on dirt or before you get there
thanhs Ken

Gooday,
First cararvan we had in recent years was a 16ft 6In Poptop Coromal the pressure hatch on it worked brilliantly.
The current one we have is a 21 Ft and 4 years ago went accross the Great Central and could have shovelled the dust out even with the Pressure Hatch open, (small & inadequate.)
Have since had two extra, much larger ones fitted approx 8in X 5 in, have not been on a long trip on dirt to prove them, have had them open on a 30Km dirt road with very good result.
The secret is to get enough air pressure build up to keep the dust from sucking in as you would be aware. One trick I have learnt is to cut a piece of foam sheet and place it between the outer & screen doors to reduce air intake ro egress there. You may have to tape some of your outside vents as well to hold sufficient pressure, but be careful you do not block one that is critical such as fridge, batteries .
Hope this helps. Do believe Trakmaster offer an internal fan system to pressurise.
Cheers,
Boroma604.

Hi Ken,
Have done a lot of research into this problem and as like other say dust always gets in.The hatches don't'' work because you drop your speed on the corrugated roads and the pressure on the inside of your van is no longer greater than the outside.
We have just picked up our new off roader from Elross and I have put a Holden commodore air filter system in. We haven't put it to the test yet but got it through Roadmasters in Adelaide. They have put it in a few vans. The air is pulled through the filter on the roof and we just turn it on a few minutes before we do the gravel roads. This then builds up a greater PSI on the inside of the van just like the coaches use to do in the luggage compartments with the Donaldson filter systems. Our van is only 2 weeks old and so only time will tell if it works. We have eliminated all wall vents in the van except for the door which we will put in a piece of foam when we hit the dirt. Our fridge has been put on a back wall and I draw air for this by fans above the fridge. The chap at Roadmasters said we would only need the one fan for a 19ft internal van.
Cheers Red Tail Black

my preasure vent works really, but only when i remember to put the put in the sink-plug