GipC if you don't mind my asking how did you trim or clean up the foam inside the return air ducts? How did you access this area? Thank you.
Very carefully....Take your time as this is a foam duct. You can damage it very easily.
Use a short piece of electrical fish tape. You can control it better. Use a smart phone and shine it up in there while you do slowly cut away at the foam. If you make a mistake, it is irreversible. You'll need someone to hold a light or get a small pen light and place it in the duct.
I don't recommend this method for just anyone.
The alternative is to just cut in a new return air and filter basically in the middle of the RV (2 total). You might consider going up on the roof and remove the A/C. Find the center of the return side and take something very sharp and small and poke it down thru the duct and into the RV. That would help you locate a good spot to cut from below.
The down side to this method is that you will increase the noise coming from what is supposed to be a quiet air system. Once again, a poor way to correct an engineering failure.
The last method to suggest...You could remove the existing Return vent and measure over to the Supply duct running thru the Return duct. The duct size is a 12" (?). Add the 12" (?) to your measurement. Get on the opposite of the blockage and cut in (2) new return vents (4 total). Others have taken this approach to reduce the noise from the unit but get an increase in the return air flow. It seemed to work for them and is a balanced approach. If you don't want to do the other (2) methods proposed, this is the preferred method (based on the others who have done this). It is quick and you reduce risks. You do have to buy the additional Return vents. Let me know if you need a source...
IF my memory is correct the 3rd ac on the 2018 GK is the vent by the shower/bath area (hallway) it is pre-wired and will need a new thermostat.
The HH if it is wired will be in the front roof vent as in the case in most units regardless of the brand (if set up for the 3rd ac which should be in the owners book)
Thank you! I have a MaxxAir fan in that location. It seems odd that it would be that far forward since the area that needs more cooling is the rear of the coach. I'm also wondering if the 3rd AC would use existing ducting or would be an unducted unit?
