[mtlakejim]

Originally Posted by DQDick

First you make sure your return airs are open using the PVC pipe. Then you open the supply vents and trim the pvc that it attaches to so it doesn't extend up and partiually block the ducts. Then, it that still doesn't work you add the third AC so that you can run all three at the same time, then you're cool. You know how I know.

Ditto here following DQDicks advice. Same result: problem solved!