Checked carrier gas fired furnace Over 10 years old system is functional but in need of a maintenance and a blower wheel cleaning also Fan motor is compromise highly recommend to replace fan motor and capacitor and clean the blower Wheel filter size16x20x1 replace filter supplied by occupant also checked for carbon monoxide no detected left system working attempted to call landlord and got voicemail left message called landlord twice and no answer office to follow up with landlord for billing