System #1 Built and installed new return and supply plenums. Installed new secondary drain pan. Rebuilt primary condensation drain and added insulation to secondary. Cleared drain with CO2 and primed trap with water. Rebuilt the flue pipe and gas pipe connections. Sealed ductwork with mastic / hardcast. Installed propane conversion kit and set proper gas pressures. Tested heating and cooling operation. System #2 Built and installed new return and supply plenums. Installed new secondary drain pan. Rebuilt the flue pipe and gas pipe connections. Sealed ductwork with mastic / hardcast. Installed propane conversion kit and set proper gas pressures. Tested heating and cooling operation. System #3 Built and installed new supply and return plenums. Installed new secondary drain pan. Rebuilt primary and secondary condensation drains. Cleared primary drain with CO2 and primed trap with water. Tested heating and cooling operation. All s