Performed comprehensive furnace tune-up on residential unit. Inspected filter (noted as getting dirty), verified clean and balanced blower, and checked all electrical components finding them within specifications. Identified water damage in upper and lower cabinets from condensate backflow through intake. Unit operation tested at maximum heating rate for 15 minutes with 70°F temperature rise (within 60-90°F specification range). Recommended installation of in-line drain to prevent further condensate damage; customer requested estimate.
