Fireplace. Tried to light pilot several times and was unsuccessful. Checked wiring and found door switch wired in series with gas valve. Disconnected and closed this circuit. Pilot was able to be lit and system cycled normal. Customer would not like to replace this switch at this time. Unit is operating normal at this time. Furnace clean and tune . Cycled system. Checked heat exchanger. Found some rust and corrosion in all chambers. No visible cracks found with camera at this time. Checked, removed, and cleaned burners and flame sensor. Both were very rusted and corroded. Found that Ventor motor bearings are worn and this is causing major vibrations and noise. This motor will seize in the future. Igniter showing signs of getting worn. Checked electrical connections and clamps. Found ventor motor boot seal was leaking. Re seated this and tightened. No further leaks found at this time. Preformed combustion test and found slightly high XS air levels in exhaust. This indicates blockage in