Did the maintenance on a gas furnace. During the maintenance I clean the flame sensor. I also cleaned out the burner box and the blower motor housing. I also do the amp reading on the inducer motor and the blower motor, both meet the furnace specs. I also did a combustion test the CO level was 52 and the O2 level was 12. Also change out the customer supply 20 x 25 x 4 filter. System is operating properly at this point. M#58STA110-22 s#2309A15491