Volvo VNL Operator's Manual page 186

Heating and Air Conditioning 181
A/C Automatic Control
When the vehicle is equipped with Auto-
matic Temperature Control (ATC), the
control panel has a button, marked with
aut
, for engaging the electronic control
unit. When ATC is engaged, the green LED
light in the button is on.
W8001471
The ATC air conditioning works with the
coolant control valve as a "thermostat,"
making automatic adjustments with input
from sensors for air output and for air in-
side of the cab. However, the fan speed
may also have to be adjusted, increasing or
decreasing air flow, to achieve correct cab
temperature.
To use the ATC, let the system run in the
manual mode until the cab temperature has
stabilized at a desirable temperature. Then
aut
press the button to engage the auto-
matic control unit. To set a new desired
temperature, simply slide the temperature
control to a higher or lower setting and the
system will maintain this new temperature
within the ability of the temperature control.
NOTE! Changing from manual to ATC
control or the other way, makes the air out-
put temperature change 5 to 10 degrees. A
small correction to the temperature control
is needed after the change has been made.