A drain cleaner apparatus for dispensing a cleaning composition into a condensate drain line of an air handler of an air conditioning system. The drain cleaner apparatus includes an apparatus reservoir configured to hold the cleaning composition, a connector interface configured to couple with the condensate drain line to cause an apparatus outlet of the drain cleaner apparatus to be in fluid communication with an opening of the condensate drain line, a dispenser device that is configured to be actuated to selectively dispense an amount of the cleaning composition from the apparatus reservoir and through the apparatus outlet, and a controller configured to actuate the dispenser device to cause the amount of the cleaning composition to be dispensed through the apparatus outlet without manual intervention.