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9 of 14
Cirrus Design
Section 9
SR22
Supplements
Section 7 - System Description
The Air Conditioning System is powered by 28 VDC supplied through
the 15-amp Condenser breaker on the A/C Bus 1, and the 15-amp
Evaporator Fan breaker and 7.5-amp Compressor/Control Panel
breaker on Main A/C Bus 2.
Distribution
Fresh air enters into the cabin distribution system through the right
leading edge air inlet (Serials before G3 Wing), lower RH cowl (Serials
with G3 Wing), and the butterfly valve on the firewall.
After conditioning, air is ducted to the cabin through eyeball outlets,
foot-warmer diffusers, and the windshield diffuser by ram air pressure
or blower fan. The vent selector on the system control panel is capable
of selecting combinations of floor and defrost outputs. Conditioned air
is also ducted directly to all panel and armrest eyeball outlets where
airflow is controlled separately by pilot and passenger(s) input.
Heating
Ram air from the upper right cowl inlet flows through the upper cowl
and is ducted to the heat exchanger. The heated air is then routed to
the butterfly valve, mounted to the forward side of the firewall, which
controls entry of hot air into the cabin distribution system. When the
butterfly valve is open, the air flows into the cabin mixing chamber.
When the butterfly valve is closed, the heated air exits into the engine
compartment and is exhausted overboard with the engine cooling
airflow.
Cooling
Cabin ventilation and cooling is provided by ram air admitted through
the right leading edge air inlet (Serials before G3 Wing), lower RH cowl
(Serials with G3 Wing), and/or the air-conditioner.
The R134A refrigerant enters the engine mounted compressor as a
vapor and is pressurized until the heat-laden vapor reaches a point
much hotter than the outside air. The compressor then pumps the
vapor to the condenser where it cools, changes to a liquid, and passes
to the receiver-drier. The receiver-drier’s function is to filter, remove
moisture, and ensure a steady flow of liquid refrigerant into the
Revision 01: 03-27-07