How to fit a caravan dust reduction system

Anyone who has towed their caravan on outback roads knows just how disappointing it can be when opening up the van late in the day, and discovering everything covered in a fine layer of dust, sucked in from the dirt roads you’ve been travelling on.

It can be worse with vans using gas appliances, as by law the van has to be vented so that if there’s a gas leak, the gas can escape into the atmosphere and not cause a nasty explosion. However, this is the 'perfect storm' for dust invading the van while you’re on the move and off the bitumen...

But there's a solution. There have been a few dust-busting products go on sale in recent years to combat this rising problem.

Some require wiring up and running a fan (a bit like a bathroom fan), but others rely on simple physics. Once installed, they all do the job of keeping the van’s interior pressurised, and hopefully keeping most if not all of the dust out.

The Dometic dust reduction system (DRS) uses air pressure to reduce the amount of dust entering the caravan when the vehicle is in motion. When the caravan is on the  move, the air in the caravan is pressurised and the DRS permits clean air to enter the caravan.

The airflow coming in then pushes out any airborne dust from within the van and reduces additional dust from entering. Most dust particles are filtered out of the incoming air and this means less dust remains in the caravan.

So when you get to your destination, you can start enjoying yourself right away without needing to spend all your time cleaning your caravan.

Testing in Australia showed that even when driving behind another vehicle on a dusty road, there was a significant reduction of dust getting in and remaining in the vehicle, compared to when the Dometic DRS was not in use. The DRS can also reduce the amount of dust and other airborne particles when sleeping in the van.

Here we're looking at a professional installation of a Dometic DRS2 into a pop-top off-road caravan.

The caravan’s layout precluded installation in the ideal spot on the roof; that is, centred 300mm from the front end of the roof, so it was agreed to install the DRS a little further back.

The Dometic DRS is intended for vehicles with roof thicknesses of 30mm to 65mm and due to the noise it creates, it’s not suitable for motorhomes or campervans.

Dometic says that some dust can still enter the caravan momentarily when there are changes in wind direction, low vehicle speeds and people getting in and out of the van.

This is in some ways a very simple do-it-yourself fitment but given the location -- the roof -- you want to be sure you have the dexterity to be up there safely, and also the skill to cut the roof open correctly, cut and re-route wiring and properly seal it later.

If there’s 240volt wiring, you must have the work done by a qualified electrician. If in any doubt, call in an expert to do the job - it shouldn’t cost much, relatively speaking, particularly if your van doesn’t have too much on the roof and has a straight-forward layout inside.

First the mounting hole location has to be selected and marked out. There's a large overlap past the actual mounting hole so you need to check all measurements to ensure there's space to mount the unit, both on the roof and on the ceiling inside.

Now is a good time to put down a protective layer on the floor and any other affected surfaces, as there will be some debris as a result of cutting the roof.

Once measurements are double checked, the corners are drilled (to ensure a neater corner cut with the angle grinder later), followed by the outer skin being cut open with an angle grinder.

Next the core foam is removed and the space checked for any wiring. In this fitment scenario, an aluminium box section was used as a conduit for wiring, so the conduit and the wiring had to be cut and wiring re-routed around the new aperture.

Next a jig-saw was used to cut though the ceiling. Then, with wiring tucked around the aperture, some Meranti timber was cut and mounted to support the aperture surround in case the unit forced the outer skins against the core when clamped together later.

Then the roof surface and the mounting surface of the DRS were cleaned and the silicone seal applied to the DRS. The Dometic DRS unit was then mounted to the roof.

Then it's time to fit the interior cover to the ceiling, which is done using attachment screws. For this the filter has to be removed to gain better access.

The hinged internal cover needs a fine mesh filter clipped into place, then the main filter can be re-fitted and the hinged section shut.

A quick clean up of silicone around the roof and a quick vacuum inside and it's job done!