Did A maintenance on a Lenox gas furnace. During the maintenance I clean the flame sensor, also cleaned out the burner box in the blower motor housing and I also wiped down the entire unit. Also looked over all the electrical connections to make sure they were tight and secure. I also did an amp check on the inducer motor and the blower motor which both meet the furnace specs. I also did a combustion analyzer test the CO level was seven and the O2 level was 17. Customer changed out to 20 x 25 x 1 filter previous to me arriving. System is operating properly at this point. Customer did not want his humidifier serviced. Also going to recommend a new water heater.m#SL280UH135V60D-03 s#5913D04283