M#TM9V120D20MP11CA s#W1B8571107. Did a maintenance on a gas furnace. During the maintenance I clean the flame sensor. Also did a combustion analyzer test test the CO level was seven and the O2 level was 18.2 also cleaned out the burner rack and the blower motor housing. Also did an Amp on the inducer motor and the blower motor which both meet the furnace specs.. customer switched out 20 x 25 x 1 filter. System is operating properly at this point. M#GMEC800603BN s#1911054361 did a maintenance only Goodman gas furnace During the maintenance I clean the flame sensor. Also cleaned out the burner box and the blower motor housing is a combustion analyzer test which check the system is only 2 years old. Also did an amp check on the inducer motor and blower motor. And also changed out the customer supplied 14 x 30 x 1 filter.