Heating - Cirrus SR22T Pilot Operating Handbook

Cirrus Design
SR22T
selection, the air in the mixing chamber is ducted directly into the
distribution system or, if in optional air conditioning mode, is further
cooled as it passes through the evaporator assembly located under
the front passenger seat. Heating is accomplished by mixing
ventilation air from the fresh air inlet with heated air provided by the
heat exchanger in the mixing chamber on the firewall. From the mixing
chamber - which also controls airflow into the cabin compartment - the
conditioned air is forced by ram air pressure or by blower fan into a
distribution manifold mounted to the center, aft side of the firewall. The
distribution manifold uses butterfly valves to control airflow to the floor
and defrost vents. Airflow is ducted directly to all panel air vents.
Crew panel air vents are located inboard on the RH and LH bolster
panels and on the outboard section of the instrument panel. The crew
floor air vents are mounted to the bottom of each kick plate. The
passenger panel air vents are chest high outlets mounted in the
armrests integral to the LH and RH cabin wall trim panels. The
passenger floor air vents are mounted to the bottom portion of the LH
and RH cabin wall trim panels. The windshield diffuser, located in the
glareshield assembly, directs conditioned air to the base of the
windshield.

Heating

Ram air from the rear ports of the intercoolers is ducted to a heat
exchanger surrounding the exhaust system crossover tube. The
heated air is then routed to the hot air valve, mounted to the forward
side of the firewall, which controls entry of hot air into the cabin
distribution system. When the valve is open, the air flows into the cabin
mixing chamber. When the valve is closed, the heated air exits into the
engine compartment and is exhausted overboard with the engine
cooling airflow.
Cabin heat is regulated by controlling the volume of hot air admitted
into the distribution system's air mixing chamber. The proportion of
heated air to fresh air is accomplished using the temperature selector
mounted on the RH instrument panel. For over-temperature protection
(the turbocharger bleed air is further heated, under some conditions
the hot air source temperature may be in excess of 300°F), the
controller monitors mixed air temperature through a sensor
downstream of the mixing chamber. If mixed air temperature exceeds
duct temperature limit, the hot air flow is reduced and fresh airflow
increased until temperature is reduced. Valves are automatically
P/N 13772-005 P/N 13772-005
Original Issue
Section 7
Systems Description
7-61 7-61