Performed preventative maintenance on furnace. Customer wanted home tested for carbon monoxide. Told him that it’s included with the service that we provide. I inspected the blower assembly, motor, capacitor, other electrical components, heat exchanger, burners, flame sensor, ignitor, gas valve, inducer motor and overall condition of equipment. I didn’t locate any compromises in the heat exchanger at this time. Just hot spots on certain areas. Blower wheel and housing were dirty, so I recommended that I clean it for him. Discussed pricing and customer approved it. I pulled the blower assembly, and disassembled it. Cleaned it thoroughly with the water hose. Put it all back together, showed customer what it looked like after and re-installed into the system. Cleaned flame sensor and dust off the burners and components. Checked thermostat operation, wiring, amps, temperatures and gas pressure. Did a carbon monoxide test and system had 0 ppm. Unit is getting older and will need to be repla