Environmental System - Cirrus SR20 Pilot Operating Handbook

Cirrus Design
SR20

Environmental System

To facilitate faster cabin cooling, prior to engine start leave the
cabin doors open for a short time to allow hot air to escape.
Standard cabin heating and ventilation is accomplished by supplying
conditioned air from the heat exchanger for heating and windshield
defrost and fresh outside air for ventilation. The environmental system
consists of a fresh air inlet in the lower RH cowl, a heat exchanger
around the RH engine exhaust muffler, an air mixing chamber, air
ducting for distribution, a distribution manifold, a windshield diffuser,
crew and passenger air vents, and associated plumbing, controls,
actuators, wiring for system flow-selection and temperature control.
An optional 3-speed blower fan is available to supplement airflow
when ram air may be inadequate such as during ground operation.
Serials 2016 thru 2064: 28 VDC for Environmental System Control
Panel operation is supplied through the 2-amp CABIN AIR CONTROL
breaker on MAIN BUS 1.
Serials 2065 & subs: 28 VDC for Environmental System Control Panel
operation is supplied 2-amp CABIN AIR CONTROL breaker on the
MAIN BUS 1.
The optional Blower Fan is powered by 28 VDC supplied through a 15-
amp CABIN FAN breaker on A/C BUS 2.
Serials 2065 and subs with Optional Air Conditioning System:
The Air Conditioning System is designed to cool the cabin to desired
temperature settings and maintain comfortable humidity levels. The
system consists of an engine driven compressor, condenser
assembly, and evaporator assembly.
28 VDC for Air Conditioner Condenser operation is supplied through
the 15-amp A/C COND breaker on A/C BUS 1.
28 VDC for Air Conditioner Compressor operation is supplied through
the 5-amp A/C COMPR breaker on A/C BUS 2.
The airplane engine must be running for the air conditioner to operate.
P/N 21399-004 P/N 21399-004
Revision A1
Airplane and Systems Description
• Note •
Section 7
7-69 7-69