Performed heat preventative maintenance on a Lennox furnace. Model #G60uh-60d-135-06, serial #5905g13991. This system is located in the basement. I powered the system down and removed the access panels. Right away I could see that the system was rusting out at the burners, gas line, gas valve and housing. This is due to a leaking humidifier that was installed on the front access panel. I also located rusting on the exhaust elbow, blower motor capacitor and blower housing. The igniter and flame sensor are both in tact. According to the homeowner he has never used the humidifier. The humidifier is shut down at the control and water valve. I cleaned out the burners and burner box as best I could due to its condition. Checked all electrical connections to ensure that they are secure and in good condition. The air filter looks like it was just replaced. I re attached the access panels and powered the system back up. I called for heat and observed the system operating. The inducer motor amp