If both the electric heaters and combustion heaters constitute a hybrid type
hot-air
heater wherein both heaters are equipped with inlets adjacent to each other and
are also housed within a frame and separated such that the air blowing systems
of each heater are independent of each other, air leakage will occur in only the
combustion heater during the heating operation in a direction opposite to the air
blowing passage of the electric heater thereby resulting in dust adhering to the
electric heater. If the electric heater is operated in this state, the dust will
be heated and then burn causing a foul odor to occur when the heating operation
first starts. Therefore, the air blowing fan 43 runs to remove any dust
that entered into the air blowing passage before the electric heater 4 runs
when the electric heater unit 4, equipped with an electric heater 44,
is performing a heating operation.
