We installed a 4 ton condenser with a 100btu furnace. We replaced all plenums and junction boxes. We added one 10" return and one 6" supply. The system has been set in a water pan and has two water detection devices. The system comes with 10 year parts and labor warranties. You must be on continuous maintenance the full 10 years to get the full labor warranty. We must return and change a 6" boot's grill out with a high velocity grill. The grill size is 10x6".