Performed furnace tune-up on 29-year-old FRP unit. Detected elevated carbon monoxide levels (25 ppm). After inspection revealed no cracks or holes in heat exchanger, cleaned flame sensor and removed debris from burners and orifice which resolved initial flame failure issue. Installed carbon monoxide/gas detectors on both floors and recommended regular filter changes every 3 months. Noted rusty burners and oily spots on blower motor for future monitoring; estimate sent for replacement parts.
