Performed annual heating maintenance in Cool. Unit is in fair condition and showing some signs of wear but nothing major. Checked igniter and is in range and okay. Checked flame sensor and was slightly dirty so I cleaned it off. Unit was converted from natural gas to LP gas. Flue pipe is not glued and is leaking condensation onto return plenum. Condensation from these types of furnaces is very acidic and can corrode the metal and rust the metal. Checked all electrical connections and all looks well, no signs of bad or loose connections. Checked the blower motor run capacitor and is in range 35uf. There is no clean out on drain lines. Repair: Glue and seal the flue pipe on the unit. The flue is what expels the harmful gasses emitted by the furnace. This pipe should be glued to make sure all the vapors are able to escape from the basement and not travel up into the home. Also glueing the pipe will stop the acidic condensation from dripping onto the unit and plenum.