In Scottsdale, near East Charter Oak Drive and North 85th Street performing Fall preventative maintenance on 2 Amana furnaces. Upon arrival, cycled unit into heating mode. Replaced filters and took temperature reading from supply and return. At furnace, cleaned and tightened electrical connections. Took volt and amp draws from components. Vacuumed and wiped down furnaces, checked all safety switches and pressure switches, gas supply with flue pipping. Homeowner stated smell coming from vents and I recommended duct cleaning, but they would like to take care of it when re modeling of home is complete. Upon departure, units are working properly and within manufacturer specifications.