TM 10-5410-228-24
When the hydraulic circuit is in the heat mode (figure 1-32) and air beam pressure is reduced to 1.5 psi for
any reason, the rib fan motor, M4, is automatically turned on. This is accomplished by applying +24 Vdc to
the coils of solenoid valves SV2, SV5, SV7, SV8, and SV9. SV2, SV5, and SV8 are opened and SV7 and SV9
are closed. This diverts the hydraulic fluid flow through the rib fan motor, M4. The speed of the rib fan is
controlled by flow control FP5 which diverts hydraulic fluid flow around the rib fan motor to limit its speed
and pressure for safety. When air beam pressure is increased to 2.9 psi, the system is returned to the
previous condition.
Valve
SV1
SV2
SV4
SV5
SV6
SV7
SV8
SV9
Energized State
OFF
ON
OFF
OPEN
ON
ON
ON
OFF
Position
Closed
Open
Closed
Open
Open
Closed
Open
Open
Figure 1-34. Static Mode, External Power, Heat Mode, Rib Fan On, NBC Off
