We have a new duct work system total of 4200cfm. One existing roof top unit has 2900cfm output. We step up the evaporator fan RPM to match 4200cfm. The room temperature set to 75-76 degree with no outside air. The inside room feel very sticky. We did some data of the existing unit. When the unit is on, Circuit 1 the head pressure-280 psi, low pressure 77psi. Circuit 2 the head pressure-270 psi, low pressure 80 psi. Return temperature is 68 F and supply temperature is 56 F. Why the unit can't property dehumidify the room?