Tested system and cleaned furnace. Removed combustion motor / burner assembly and gas valve. Cleaned burner assembly and soot behind combustion motor. Tested inlet and output LP pressure and found low input pressure. Adjusted home LP regulator from 10.28 to 11.83. Tested input pressure for furnace and achieved 10.0 input. Tested in both high and low fire and confirmed proper LP pressures for 4.5 and 10.0. Before the pressure could not achieve 10.0 before the regulator was adjusted.