Boeing 737-800 Temperature Selector

[h3dxb]

Gents

Temperature Selector

The control and passenger cabin temperature selectors are identical unit
mounted on the forward overhead panel. The face dial is divided into an
AUTOMATIC and MANUAL range. The left temperature selector controls the
control cabin temperature. The right temperature selector controls the temperature
of the passenger cabin.
The temperature selector has two modes:

MANUAL

In the manual position, the selector provides direct control of the mix
valve. In MANUAL, turning the knob clockwise to COOL causes one of the
cams to close a switch connected to the mix valve actuator motor, and operate
the valve to increase the proportion of cold air passing through the
valve. Turning the knob counterclockwise to WARM causes the cam to
close a switch connected to the mix valve actuator and operate the valve
to increase the proportion of warm air passing through the valve.

AUTO

In the automatic position, the temperature selector provides the selected

input signal to the temperature regulator for cabin temperature control.

With OFF is meant AUTOMATIC MODE is OFF.

Hope this helps.

Rgds