Today I arrived on site and performed a winter tune-up on the system. Here’s a summary of the work completed: **Filtration:** * Replaced the antimicrobial filter with the customer's spare 20x30x1 filter. * Checked the filter. **Indoor Unit (Furnace in Closet):** * Confirmed the indoor coil is in good condition. **Outdoor Unit (Straight Cool on Side of House):** * Confirmed the outdoor coil is in good condition. **System Components (Inspected and Working Properly):** * Blower wheel. * Burners. * Exhaust flue. * Heat exchanger. * Electrical wires secured. **Carbon Monoxide Testing:** * Tested for carbon monoxide; result was 0.00 PPM. **Temperature Readings:** * Return air temperature: 68.0 Degrees Fahrenheit. * Supply air temperature: 109.2 Degrees Fahrenheit. **Condensate Drain System:** * Cleared the drain line. * Tested the safety switch. * Confirmed the drain line is strapped. **Other:** * Dusted the return grills and thermostat. * Restored p