Came out to perform preventative maintenance on furnace. Discussed with customer about maintenance being performed, filter needing changed, and any issues she may be having. Customer stated the filter does need to be changed and that the system is running fine as of right now. I changed the filter in home for customer. Inspected the blower assembly, motor, electrical components, heating components, heat exchangers, drains, and overall condition of equipment. Found blower capacitor reading out of tolerance and customer had me replace that. I cleaned the flame sensor and dust of the burners and components. Checked thermostat operation, zoning, amps, temperatures and gas pressure. Found downstairs thermostat is a little finicky when it comes to changing modes and fan from auto to on. Let customer know that the thermostat will need to be changed eventually due to the inconsistencies when setting it. Customer will look into having it changed out next service. System is heating properly at t