User manual

Piper PA-31T Cheyenne X
Aerosoft GmbH 2007
54 55
54 55
is provided by engine bleed air through a bleed-air shutoff valve and
bleed-air ducts from each engine.
Bleed air to the ECS is controlled by a pressure regulator/shutoff valve.
This valve can be selected for high and low airflow via the ECS SELECT
Switch (3). The ECS SELECT Switch (3) must be in the LO position for
engine starting, takoff and landing. The HI position may be used on
the ground to provide maximum heating or cooling. When in HI Positi-
on, an annunciator light labeled HI BLEED ON will illuminate.
A pressure regulator shutoff valve bypass is installed. This valve
supplies a minimum of bleed-air flow to a jet pump which induces air
from the raim-air inlet to mix and supplement bleed-air flow and conti-
nues to sustain pressurization. The ECS bypass valve has a manual and
automatic control circuit, controlled by the ECS REG BYPASS Switch
(1). The up position (ON) of the switch will open the bypass valve and
close the pressure regulator/shutoff valve. These two functions will
also occur automatically if either propeller control lever is moved to
the feather position. When the ECS bypass is ON, an annunciator light
labeled ECS REG BYPASS will illuminate. The pressure regulator/shutoff
valve will automatically close if
ECS overpressure or
ECS overtemperature exceeds the values set by a pressure
switch or the thermal switch sensing temperature
The primary function of the ECS bypass is to reduce engine bleed-air
requirements to a minimum during engine-out operation. The system
should, however, be manually selected if either an ECS overpressure or
overtemperature occurs.
The temperature control system consists of a temperature controller,
a mode switch (2) labeled AUTO and MAN, a temperature selector
rheostat knob labeled COOL and WARM (4), and a MAN TEMP CONT
Switch (5) labeled HEAT and COOL. The MAN TEMP CONT switch (5)
is spring-loaded to the center position. When the mode switch (2) is at
AUTO, the temperature controller is armed, and input from the tempe-
rature sensors in the cabin and the temperature selector rheostat knob
is processed to adjust the mixture of hot air with the super cooled air
to produce the selected temperature. To achieve manual control, the
1.
2.