Dust can introduce problems when it enters living spaces. It clogs electronic equipment which prevents air flow. It attaches itself to grease thus impeding lubrication like in DVD players. It provides an absorbing surface which harbors moisture that can create mold. It collects in ducts which are difficult to clean. It collects within the living space requiring frequent vacuuming. And worst of all it collects in your nose, throat and lungs. Efforts to remove dust, clean it up and/or not let it enter in the first place are well worth the effort. Below is a simple system I employed to help with dust control.

Our bus is pretty tight but not perfectly tight so dust finds its way in. Commercial buildings use filtered air to keep the interior at a slight positive pressure to prevent dust from entering in the leaky areas. No living space is completely tight and you wouldn't want it to be either. The goal is to keep air flow from the living space. Using that principle, I modified the kitchen Fantastic vent to help keep dust out. I did this modification about 4 years ago and it's worked reasonably well. Below are the basic points of this modification:

Vent cover used to hold filter material in place.

1) I purchased a plastic vent cover and drilled out the
pattern using four different sized hole saws. That
removed as much plastic as possible, preserved cosmetics,
allowed good air flow and retained structural integrity.

2) I installed a reversing switch in the fan to control the
direction of air flow. You'll need a DPDT center off

3) I purchased 1" high quality polyester filter material and
cut that into squares that are slightly bigger than the
fan opening. Did this to ensure a tight fit.

4) Installed clips that come with the vent cover. Placed some
stick-on Velcro dots on the fan side of the vent cover.
Placed filter material on vent cover. Installed vent cover
over fan with filter material facing the fan.

A reversing switch was installed to replace the OEM rocker switch.

The plastic vent cover is an inexpensive kit available from your favorite camping store which fits standard vent fans. It comes with a plastic cover, clips, screws and an insulation pillow. The cover is solid so you'll need to drill it out as shown. I took measurements of all the islands suitable for drilling and made templates. Using simple layout techniques I located the center of each shape and figured out the largest hole that could be drilled. For my cover it worked out to be 4 different sizes. A bi-metal hole saw used carefully (slow speed and easy feed) worked well for drilling the holes. Follow this up with a chamfer tool to clean away the burrs. You'll get nice looking clean holes using this method.

21 holes in 4 sizes makes for good air flow. This cover comes solid. Drill holes as you see fit.

Once you drill out the cover (most of the work in this project) you can install Velcro dots on the fan side to help hold the filter material in place.

Velcro dots helps hold filter material in place. Install them as required.

On my fan I needed to lose the OEM on/off rocker switch as it didn't allow reversing the polarity of the motor. Reversing the motor polarity is required to reverse the fan's rotation and thus its air flow. I used a DPDT center off toggle switch and made a simple metal plate to mount it. You'll need to gain access to the motor wiring to hook this in. The center off maintains the function of the OEM switch. Make sure to let the fan blades stop before changing direction. It's easier on the motor and avoids blowing a fuse perhaps.

Polyester filter material 1" thick. Don't use junk here!

You can discard the insulation pillow that comes with the vent cover kit. Install clips and screws per the instructions. Cut a piece of filter material just a bit larger than the fan opening so it's tight. When you install the filter material, make sure it's oriented in the proper direction. Air should flow from coarse to fine. With filter material on the cover, slide cover into the clips. Fan direction should be set to bring fresh air into the living space.

This air flow direction will slightly pressurize the interior of your bus. Filtered air thus leaks out leaks in the bus helping to prevent dust from entering there. I've had good luck with this approach. In cases of more severe dust you may want to do mods on both fans (kitchen and bathroom) to increase the effects to handle more severe dust.

My fan turns on/off via the Intellitec push button located under the kitchen counter top. Obviously the controls of the fan are inaccessible with the filter in place. They can be preset to your liking, however. For cooking, you'll need to remove the filter and set the fan to exhaust. If this is too much trouble or inconvenient then this modification isn't for you.

Something else you need to know. Fantastic DOES NOT recommend using any filters with its fan products. Here's why I think they make that statement. My 3 speed fans use a resistive element (not a pulse width modulated) speed control. On speeds 1 and 2 this element generates heat. Some of the air flow is used to blow over this element to dissipate heat. My guess is that if people put filters over their fans which become clogged, due to irresponsible usage, cooling air may be lost to the resistive element. That could lead to excessive heating and perhaps a fire. Also the heating element can collect dust balls which are perhaps flammable. So I'm not recommending my filter solution to the great unwashed as a general hedge against dust. There will always be that idiot that will use it inappropriately. So today's solutions must take into account the dumbest user.

That said, I've not had any problems with what I've presented. I make sure to keep the filter clean and air flowing properly. On fan speed 3 (fast), the heating element is out of the circuit. That removes only one source of heating, however. One should consider the fan motor itself and the required air flow over its casing which creates cooling.

As previously mentioned, the switch allows the fan to be returned to exhaust (OEM default) as required when cooking. When exhausting, you'll want to remove the filter which is an easy task. The center off allows you to stop the blade before reversing its direction thus avoiding excessive current draw from the motor as it fights the direction change. Again be advised that Fantastic DOES NOT recommend using any filters with its fan products.

Slide show HERE. (11 frames with captions)
Evolve and simplify!
Scott Bridgman, Why not join and post your own comments??
scott@muniac.com (email me)