Performed 2 system heating maintenance on 2015 Daikin Furnaces. Checked amps, capacitors, filters, cleanliness, electrical, blowers, flame sensors, pressure switches, and safeties. U/s is working to manufacture specifications. D/s is in rough shape and tripped on open pressure switch. Inspected flue and discovered that it hardly breathing. Both blowers and caked in dust. D/s electrical is burning. System has an external filter that is full of growth cycling growth into the house. Provided options for repairs, upgrades, and a system replacement for d/s.