Cessna 150K - Defroster System; Ventilating System

14-7. DEFROSTER SYSTEM.
14-8. DESCRIPTION. The defrosting system is
comprised of a duct across the aft side of the fire-
wall, a defroster outlet, mounted on the left side of
the cowl deck immediately aft of the windshield, and
flexible ducting connecting the
system.
14-9. OPERATION. Air from the duct across the
aft side of the firewall flows through a flexible duct
to the defroster outlet. The temperature and volume
of this air is controlled by the settings of the heater
system control.
14-10. TROUBLE SHOOTING. Since the defrosting
system depends on proper operation of the heating
system, refer to paragraph 14-5 for trouble shooting
the heating and defrosting system.
14-11. REMOVAL, INSTALLATION AND REPAIR.
Figure 14-1 may be used as a guide for removal, in-
stallation and repair of defrosting system components.
Cut hose to length and install in the original routing.
Trim hose winding shorter than the hose to allow
clamps to be fitted. A defective defroster outlet
must be repaired or replaced.
14-12. VENTILATING SYSTEM.
14-13. DESCRIPTION. The ventilating system is
comprised of an airs coop mounted in the inboard
leading edge of each wing, an adjustable ventilator
mounted on each side of the cabin near the upper
corners of the windshield, a fresh airscoop door
mounted on the right side of the fuselage, a control
knob on the instrument panel and flexible ducting
connecting the system.
14-14. OPERATION. Air received from scoops
SHOP NOTES:
14-4
mounted in the inboard leading edges of the wings is
ducted to adjustable ventilators mounted on each side
of the cabin near the upper corners of the windshield.
Forward cabin ventilation is provided by a fresh air-
scoop door mounted on the right side of the fuselage,
just forward of the copilot seat. The scoop door is
operated by a control in the instrument panel mark-
ed "CABIN AIR." Fresh air from the scoop door is
routed to the duct across the aft side of the firewall,
where it is distributed into the cabin. As long as
the "CABIN HEAT" control is pushed in, no heated
air can enter the firewall duct; therefore, when the
"CABIN AIR" control is pulled out, only fresh air
from the scoop will flow through the duct into the
cabin. As the "CABIN HEAT" control is gradually
pulled out, more and more heated air will blend with
the fresh air from the scoop and be distributed into
the cabin. Either one, or both of the controls may
be set at any position from full open to full closed.
14-15. TROUBLE SHOOTING. Most of the opera-
tional troubles in the ventilating system are caused
by sticking or binding of the inlet s coop door or its
control. Check the airscoop filter elements in the
wing leading edges for obstructions. Also, check
the filter elements in the inlet scoop door ( 1971
Models). The
elements may be removed and cleaned
or replaced. Since air passing through the filters is
emitted into the cabin, do not use a cleaning solution
which would contaminate cabin air. The filters may
be removed to increase air flow. However, their re-
moval will cause a slight increase in noise level.
14-16. REMOVAL, INSTALLATION AND REPAIR.
Figure 14-1 may be used as a guide for removal, in-
stallation and repair of the ventilating system com-
ponents. A defective ventilator or scoop door must
be repaired or replaced. Check for proper opera-
tion of ventilating controls after installation or repair.