My latest DIY improvement to my 2015 Vista 27N.
I recently read about an aftermarket product from
RV Airflow Systems to better direct the air out of the rooftop AC into the ceiling ducts improve AC performance and cut noise. In the stock Coleman Mach / Winnebago design the air blows straight down thru a rectangular opening into a air space inside the outlet side of the AC. The ceiling ducts intakes are rectangular holes on 2 sides, so there is a lot of turbulence generated. There is no smooth air flow from the AC into the ducts. This reduces the air flow and increases noise. Their product is foam insert or inserts that smoothly turn the air coming down into the ducts.
My unit has the ChillGrille and their product did not appear to be compatible with it, they blow all the air into the ducts and don't provide a path for air to exit thru the ChillGrille when desired. Also, it looked like I could home brew something for $ 10 worth of stuff and some of my time, and still be able to blow air out the ChillGrille to rapid cool down the RV living room. So, here's all the AC optimization effort ...
1. You remove the air filter, then remove the ChillGrille by taking out 7 screws.
2. I noticed that the the blower outlet was partially blocked by an OEM Coleman Mach foam piece due to how someone assembled the unit at Coleman Mach. I trimmed the foam to get the full blower outlet opening.
3. I noticed that the inlet side had a lot of loose styrofoam beads some partially blocking the AC Evaporator, others just laying around up in there. I brushed and vacumed them out, getting about 1/4 cup of them in my particular unit.
4. The low and high voltage wires enter the inlet side thru a large hole that was not sealed, I sealed it up with metal duct tape.
5. I neatly dressed the wires in the inlet air space using some cable ties to minimize how much they block air flow.
6. At some point the freeze sensor had fallen out of my AC evaporator, be sure to push it back into the same bent fin location it was after cleaning and dressing wires if it's not still in the evaporator.
7. In my unit air was leaking from the outlet side to the inlet side as the 3 OEM Coleman Mach screws were not sealing to the divider well except in the middle. Added a self drilling screw on both ends by the divider to resolve. [Note: this step actually is done when replacing the ChillGrille before putting the air filter back on.]
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Now the actual airflow mod ...
1. I fabricated from a piece of 6" round furnace duct material a diverter to turn the air blowing straight down sideways towards the two duct openings. I cut the furnace material into a half circle and folded it with a 180 degree bend in the middle. The piece has a point facing up and two 90 degree curves coming down from the point each way. I centered it below the blower outlet opening, securing it into place with metal duct tape.
2. Used metal duct tape to make a taper from the top of the two duct openings to the blower outlet openings, and curved the tapers around the sides.
3. Did some final dressing with metal duct tape to try to make sure all the air had to go into the ducts or out the ChillGrille.
4. Finally, Replace the ChillGrille and the inlet air filter.
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Project took about 2 hours. It seems to make the AC slightly quieter. Can't say how much improvemement it will give me for cooling but it can't hurt.
Linear Mode
