View Full Version : AC Airflow

06-28-2007, 05:42 AM
My question concerns the questionable choice of materials for installing the ac duct outlets in my 2008 Big Country 3300RL # 9084. The method of using foil tape to seal the air gap between the ceiling space and duct board was a poor choice as it created a poor air flow condition in my unit. After an inspection of my ac system I found several factors of concern. First nearly every outlet out of the seven had the air flow partially blocked by the foil tape. Since short strips were applied in a vertical manner the tape ends curled up from the duct board inside the outlet and created just enough restriction of air flow. I pressed this back into place and inspection the duct trunks for collapse and gaps as well but found no issues. Secondly over 50% of my curbside supply outlet from the ac unit was blocked off by white insulation tape, also excess roof membrane extended into the ac unit opening because it was not rolled over and secured to the side walls of the opening thus contributing to the poor air flow issue too. I encountered some minor taping issues in side the ac unit as well that was allowing supply air to cross over into the return side without being distributed through the duct work system.

I hope this process in your manufacturing has been improved since my unit was constructed, if not here are a couple suggestions. First insert a plastic grommet type arrangement whereas a ring with a shoulder, similar to the outlet grille, is installed inside the duct board at each opening. This ring would slip over the outlet grille when it is installed and any air leakage could be fixed with an o-ring. Option 2 would be to insert a 1 thick piece of rigid Styrofoam between the ceiling material and duct board. The piece should be cut about 8-inches square with a 5-inch center hole to allow the duct grille to be inserted through it. Both arrangements would seal the ceiling space gap from the conditioned air and add some additional strength around the duct opening.

I have pointed these deficiencies out to my dealer and he has my unit on his lot to repair them as I am writing to you. Overall I feel you have assembled a fine fifth wheel and was the reason I chose a Heartland product and waited 7 weeks for this unit to be delivered. But none of this mattered the two times we have been camping in 90+ temperatures fighting with keeping the ac unit operating.