Found water back flowing into secondary drain pan and overfilling onto platform. Removed the junction to the secondary pan and installed additional condensate overflow safety switch wired in series with the secondary drain safety switch. Installed cap on the old junction takeoff to make the primary drain a straight shot to the bathroom sink. Removed the bathroom sink rubber hose and cleared debris, also tested primary drain with water and watched condensate exit the system properly. Tested system on cooling and monitored for 20 mi to assure system is working properly.