Performed preventative maintenance on Coleman furnace. Model number: Tg9s080b12mp11. Serial number: W1f8890434. Upon arrival the unit was off at the thermostat. Turned the unit on at the thermostat. Went downstairs and watched the unit run. Turned the unit off at the switch and turned the gas off to the furnace. Removed the panels. Checked all electrical connections to make sure they were secure. Checked the blower motor and fan for any dust build up. Checked all pressure switch tubes for any blockage. Cleaned the flame sensor. Cleaned the burners. Filter was recently changed by the homeowner. Performed a combustion analysis. CO 58 ppm. Co2 8.9 %. Poured water into the condensate pump and watched the water pump out properly. Heater is running properly at this time. Performed preventative maintenance on a Coleman AC system. Model number: Tc4b3621h. Serial number: W1g8969392. Switched the thermostat to the AC system. Went downstairs and watched the unit run. Turned the unit off at the s