Diagnostic Service Call. Went out to find furnace overheating due to dirty filter. Remove filter and still did for inspection. Found multiple cleanliness issues, and signs of corrosion on heat exchanger. Went over options for cleaning system and advise due to the age there is no promise reliability with that old of a furnace. Due to cost of repairs to possibly have other issues they decided to look into system replacement and decided to move forward with a full dual fuel system replacement.
