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gossamar · 02-27-2022, 06:37 PM

This system is similar to what the Redwoods and Rushmore lines from Crossroads have and they are not without their issues. I also experienced trouble keeping the camper cool on a 90-degree day and started to do some investigating.
A couple of notes on what I found and corrections I have made, hopefully that can help some of you out.

1. I have two 15K- AC's ducted into one racetrack similar to what is above. The supplies are ran above the returns and are very problematic to crushing the returns, not allowing for proper air flow.

2. The original design only allowed for 2 return ducts per 15K AC, which did not allow enough return air flow to the units, causing freeze up issues.

3. The round supply diffusers, included a round "baffle" that went up into the supply duct to capture the air. The supply diffuser also by design, allowed for about a 1/2" gap between the duct and inside roof panel.

Steps to Correct...I snapped some photos of inside the return ducts and noted the smashed ducting, doing the old fashion tissue test, when running it would barely move the tissue.

A. I first cut 2-additional 6x9 return vents on EACH AC return duct and also foil taped the area where I cut. From there, I used rigid styrofoam to push the crushed section where the return goes under the supply back into shape....this must be done from each side of the return. A test of the additional return ducts and re-supported ducting with the tissue test, the return now almost took the tissue out of my hand.

B. I remove each of the supply diffusers, removed the plastic baffle and proceeded to foil tape every opening around the opening ring of the supply.

I also did some temperature checks and I improved my delta T temps by several degrees. I am seeing with one AC running about a 20-degree difference between return and supply. When two AC's are running, the number jumps to 25-30 degrees. I have seen supply air temperatures in the mid to upper 40-degrees when things really get rocking.

It should also be noted that prior to this modification, I cleaned both AC coils at the beginning and half-way through the camping season.

Again, hope this helps...

02-27-2022, 06:37 PM	#12
gossamar New Member Join Date: Aug 2007 Location: normal Posts: 2 M.O.C. #7543	This system is similar to what the Redwoods and Rushmore lines from Crossroads have and they are not without their issues. I also experienced trouble keeping the camper cool on a 90-degree day and started to do some investigating. A couple of notes on what I found and corrections I have made, hopefully that can help some of you out. 1. I have two 15K- AC's ducted into one racetrack similar to what is above. The supplies are ran above the returns and are very problematic to crushing the returns, not allowing for proper air flow. 2. The original design only allowed for 2 return ducts per 15K AC, which did not allow enough return air flow to the units, causing freeze up issues. 3. The round supply diffusers, included a round "baffle" that went up into the supply duct to capture the air. The supply diffuser also by design, allowed for about a 1/2" gap between the duct and inside roof panel. Steps to Correct...I snapped some photos of inside the return ducts and noted the smashed ducting, doing the old fashion tissue test, when running it would barely move the tissue. A. I first cut 2-additional 6x9 return vents on EACH AC return duct and also foil taped the area where I cut. From there, I used rigid styrofoam to push the crushed section where the return goes under the supply back into shape....this must be done from each side of the return. A test of the additional return ducts and re-supported ducting with the tissue test, the return now almost took the tissue out of my hand. B. I remove each of the supply diffusers, removed the plastic baffle and proceeded to foil tape every opening around the opening ring of the supply. I also did some temperature checks and I improved my delta T temps by several degrees. I am seeing with one AC running about a 20-degree difference between return and supply. When two AC's are running, the number jumps to 25-30 degrees. I have seen supply air temperatures in the mid to upper 40-degrees when things really get rocking. It should also be noted that prior to this modification, I cleaned both AC coils at the beginning and half-way through the camping season. Again, hope this helps...