99M90
21-40-01
Page: 2-5
Rev. New
Issued: May 9, 2012
I-Series Combustion Heater
Owners Manual
DESCRIPTION
2.1
Component Operation (cont’d)
Air Blower
This blower is attached to the inlet end of the heater assembly and provides a source of
ventilating air through the heater. Ram air from the ventilating air intake scoop is normally
used during flight. The blower can run continuously unless some provision is made to
shut it off during flight and use ram air exclusively. The power line should be the circuit
interrupted by a switch, not the line from blower to ground. (See Figure 2.5)
Combustion Air Blower
(See Figure 2.6 & 2.7)
This centrifugal type blower is normally mounted separately from the heater to permit more
flexibility for installation. It supplies combustion air to the combustion chamber of the
heater typically from outside air. (See Figure 2.7) Performance of the combustion air
blower is assisted by the use of ram air during flight. The type of blower and mounting
location are typically controlled by the aircraft/rotorcraft design holder.
FIGURE 2.5
Typical Vent Air Blower Assembly
FIGURE 2.6
The Combustion Air Blower Ass’y
Figure 2.7
CA Blower Air Inlet (Typical)
Air Inlet
