Customer has a oil fired furnace in crawl space, customer had made some repairs to furnace with new burner motor and primary control due to water damage and had also place flex duct tape on chimney flu piping, the smell they are smelling is the foil tape melting, chimney flue just needs screws not masting tape, took combustion test of system which everything is normal, blower came on, had a 45 degree delta t reading, customer did sign up for maintenance agreement for one oil fired furnace system hasn’t been serviced in a few years. System is operational and working. :