Let's brainstorm a dash air solution

[Oldchinahand]

So, I've got the lower dash skirt off (again), to facilitate replacing the carpet in the entry well.

There is a grill in the dash skirt covering an intake port for the dash air. The port has an open grill, no filter, that brings inside air directly across the ac chill fins then the air is ported to several places. Unfiltered, the amount of dust sucked across the fins and distributed thru the ducting is significant -- even after replacing the carpet (except the entry well vertical surfaces). So, what I have been doing is attaching a piece of activated charcoal filter medium over the air intake using a narrow strip of carpet tape. Not elegant, but we believe we notice the difference in air quality.

Problem is, to change the filter, the entire dash skirt must be removed. (Because three pieces have to be removed left to right and replaced right to left.) Thought about cutting an access port but that becomes a structural integrity problem as well as an esthetic issue.

Willing to entertain any solutions put forth by any of you shade tree engineers out there. Yeah, the photos are askew. Difficult to rectify using my phone.

Fair Winds and Following Seas.

[Morich]

I'm not up on that model so don't know what I'm looking at. Is the area near the blower the intake and outlet the plastic grid in first photo? I'm assuming the blower motor normally gets a cover put back over it?
Thinking maybe there would be a way to build a pre-filter like thin sponge to slide in under the skirt to simply lay against the intake filter you have? Thinking like is done on fish tank filters to make the main existing one not need cleaned so often.
Thin filter media of this sort is pretty easy to find and cut to fit.
But also pretty vague about where things lay out, so correct me, please!
Would turning the phone 90 degrees make the pics come out upright?

[Goodspike]

I'm not sure what I'm seeing either, but if the louvered vent area is where the air comes in, could you cut off some of the louvers (maybe all but the first, last and middle??) and then use one of these cat water filters, black side out in the hole?

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

They are pretty rigid (maybe too rigid) and 5.5" high and slightly tapered in width (3 1/8th to 3 3/8th).

[Winterbagoal]

Why not cut a piece of the filter material to the size of the grill that covers the air intake, and tape it in place there (two-sided tape?) instead? On the outside of the dash panel over the grill? As you say, not elegant, but functional.
Or, fashion some sort of grill cover, that attaches by poking through the louvers, with the filter material in it? Again, not pretty, but functional.

[Bones2003]

I believe the vent that is under the blower in your picture is used to recirculate air from inside the cabin when you have your dash AC set to MAX AC. Otherwise, external air is sucked into the system from a similar vent that is outside the cabin. So, are you saying that you have excess dust inside your motorhome that you are trying to stop recirculating? Seems like most dust would come from outside the coach. I believe that I've seen posts from others that have attempted to add some type of air filter outside the cabin to reduce external dust/pollen/etc. Not sure how to search for that topic.

[Oldchinahand]

Yeah, sometimes hard to visualize looking at pieces parts.

The dash skirt is comprised of four interlocking pieces of flexible plastic about 3/16in thick starting at the fuel pedal and extending to the passenger side. The panels screw to the floor in four places and "float" along the top edge where they interlock with the upper dash..

The top photo shows the passenger side panel cleaned and sitting on our EasyRest sofa. The round holes are for fittings for cool air discharge into the cabin. The louvers line up with the ac cabin intake air port.

The second photo shows the ac blower housing above the air intake grill and top entry step.

The third photo shows the ac blower housing above the air intake grill which is covered with a piece of activated carbon filter media. Applied with carpet tape.

Yeah, if I am at my laptop or tablet it is easy to rotate the photos. Wallowing around under my dash on a balmy Tucson summer afternoon with my S9 in hand is different.

Valid point re: MaxAC. I have pored over the diagrams and wormed into every void I or my inspection mirror fit into looking for that outside air intake. Actually, we normally drive using MaxAC until our shoe soles start melting then fire up the Onan and basement air.

Appreciate your thoughts. Keeps my thinking juices going. What I have done so far.....

Since the skirt is off anyway, I used plaster to pull a pattern of that curved area to the right (up in the pic) of the louvers. After it dries, I intend to put it in the oven with a piece of scrap plexi and see if I can't make a good looking little curved hatch. Have to take this slow. SWMBO has a low tolerance for redneck engineering.

Fair Winds and Following Seas

[NeilV]

Yes that would only solve the issue with dust when the system is on recirculate and not when running in the normal fresh air mode.

The right hand side of the 2nd and 3rd pictures is the bottom and shows the bolster on the right side of the top entrance step of a diesel pusher. A filter that small would tend to clog pretty quickly so it would likely require frequent changing so yes a better method is required however again this would only be for the Recirculate or MAX cooling mode which the restriction of the small filter would likely make moot and have absolutely no benefit in Normal mode operation when outside are is being drawn into the coach.

If you really want to just filter inside air you may want to consider making a holder for a standard cabin air filter designed to pass the volume of air required for the AC and dash system and then modify the plastic skirt panel using a plastic welding iron to finish it off for structural integrity. The skirt is not air tight so surface mounting the filter over the intake louvers would be of little benefit.