Cleaned and serviced oil furnace. The furnace looks like it hasn’t been serviced in years. The filter was plugged, the strainer was plugged and the nozzle was covered in soot and gunk. Replaced all 3 of them. Cleaned the flue piping. Recommended some repairs which the customer did nit want to do at this time. Ran a combustion test and tested the system operational. The system is operational at this time.