Came out for Home Care heating and cooling check. Home has new 2025 Daikin Communicating AC/Furnace for 1st and 2nd floors. For 3rd floor system is 2019 Trane AC/2007 Ruud Furnace. Changed out 2 16x25x1 filters. Cleared condensate lines, verified draining properly into plumbing stack located in garage closet. Daikin system has TE Standard flood protection, upstairs system only has pan switch. Upstairs system has no UV protection, main floor UV light is operational. Both outdoor coils have dirt and debris. Found Trane system appearing low on charge due to low temp split and low subcool. Verified both systems cooling and heating at this time. When inspecting upstairs heat exchanger did find signs of rusting. No apparent cracks and carbon monoxide detector did not pick up anything. Spoke to customer about these findings and main recommendation is to have install supervisor come out to discuss new furnace options due to age and condition. For current Trane system spoke about possibly repla