Performed heating maintenance on a 2017 Lennox single stage 93% efficient natural gas furnace 16x25x1 filter is new Pulled and cleaned flame sensor Checked Condensate drain tubing between inducer outlet and collector box Found rust damage from apparent water leak on left side outlet of collector box Could not remove drain plug without taking return duct off Used silicone on it as an attempt to stop the leak Blower capacitor measured 4.9mfd (spec 5mfd) Found blower caked in drywall dust Got approval to pull and clean Disassembled blower and washed with water and a brush Reassembled Run tested furnace Gas pressure 3.5" Temperature rise 62⁰ (spec 40-70) Furnace operating within factory specs at this time