Dometic dust reduction for vans

RI.
I had a look and read of the site. Just an obstructing frontal area to catch air and a $50 filter AND you have to cut a whacking great hole in the roof to do the fitment. All for a meagre $650 initial cost. Surely there are other ways. Yes, it might work but no moving parts or technical bits just a filter. I presume by it's design the faster you drive the more air gets filtered.
Unless travelling in someone's dust where it may be of benefit, is it possible to modify the shower vent area of a van or high up air vents to make it pressurize clean air flowing past/over the van?
I would be happy with a small fan to create pressure internally and use it when dust conditions are present and it will work at low forward speed and not depend on frontal wind direction.

Hi Rusty Iron,

There are a number of better options for dust ingress prevention out there. The most efficient use a fan through a filter to pressurise the van. Dometic do make one, Carafan is another. From what I have read, you can replace one of the existing “skylight” vents in the van with a pressurising fan. Not sure on price, but would be far more efficient as they do not rely on driving speed to provide sufficient air volume/pressure to work.

Macca.

The system in our OKA is very simple.
1. Seal up every crack you can find. Bright lights inside at night help.
2. Add a ram air vent up high. It is always open and has a torturous path to stop the ingress of water.

Fact is, if the holes are all sealed, the air flow into the vehicle to pressurise it is extremely low.
If there is no forward speed, there is also no dust coming in either.
It has no filter.., just some s/s flywire to keep the bugs out.
It doubles as the vent required for the gas installation.
We get almost zero dust inside. It works.

Cheers,
Peter
OKA196 motorhome

I have read a number of posts (van facebook threads) by people who have fitted them and they seem to happy.... and they seem to work. There really isn't much about that looks ok at this price point... you jump to a bit over $2k for the powered units.

Ok, after more thought, I've decided the Dometic unit won't work for me. Neither will the passive, snorkel type. We do a lot of remote touring around WA, and other places when the borders are open. We spend almost as much time on gravel as we do bitumen, more on dirt on some trips. A lot of it is at low speeds, 10 ~ 15 kmh or less because the tracks are often rough. I've had a number of occasions where we've had a tail wind and the dust overtakes us. So I figure there's no point having a system that will only work with forward motion to scoop air, if we are travelling too slow for it to work properly or the wind is coming from the wrong direction.

I'm going for a DIY option with a Donaldson type air filter, with a bilge fan behind that to draw air through it, and then an elbow, to tubing through the roof of the pop top. Use a speaker grill or similar on the inside. This is going onto a new van and talking to the dealer yesterday, the roof looks like the only suitable place due to the construction of the van. Although, once I get the van and I can have a good long look and think, I might look at the front boot as an option for the air cleaner body and run a pipe up to the roof line with a snorkel on top of that for the intake. The outlet could then be ducted under the bed, exiting at the end of it similar to the caravan heaters.

I think there's a couple of advantages to this. It will work no matter how slow we go. And I've seen some people say that it can help to cool the van down, if you've been out for the day and the weather is warm. Turn the system on and help to expel the hot air. The bilge fans draw around 2.5 to 4.5 amps depending on the type, but with 2 x 120 lithium batteries in the van that won't be an issue.

It looks like the bits would add up to around the 300 ~ 350 mark, so less than half the price of the Dometic installed. It will be a bit fiddly to install it all but I reckon it will work a lot better for our situation. And there is no way in the world I'll pay up to $2.5k to have a Carafan fitted. As nice as that would be...

Thanks all for the responses and I'll report back once I've got it done. Pick the van up 1st October.

Hey Rusty

I have just installed a 75mm bilge blower (continual) in my 17.6 full caravan.
It is yet to be tested on road.
I have a microwave vent high on the right hand side of my van so no new hole was required.
I used 90mm storm water pipe to connect to the blower and then the flexible hose to a heater outlet.
I intend to fit a filter where the air comes out as it is too difficult to remove the microwave just to service a filter.
I wired in a cigarette plug as it only draws 2.5 amps and it plugs into the wall where my 12 volt television is connected to .
I may be wrong with the filter bur time will tell

This setup incorporates a pre filter to spin out larger dust particles then balance of air flow is sucked through a Donaldson filter by a centripetal fan. I have it set up to turn on by turning on my clearance lights.
These units are available from Lyons WA and are commonly used in vehicles in the mining earth moving industries.
I think you will need good positive pressure in extreme bulldust I certainly did.
Expensive to buy or DIY

I've gone the KISS route in regards dust ingress, still use the basic roof dust hatch but with a cowling over the top so when the hatch is open it seals the back end & makes for a larger Air-ram effect, when the hatch is closed air & bugs just flow straight thru. Inside I have a removable (washable) filter. As stated in previous posts all gaps have been resealed & larger vents have clip on/off covers. Its not "open" when its raining & dosen't use any power, and it "works" extremely well even in bulldust situations