Volvo FM Handbook page 347

336 Cab
Start the heater with timer setting
ADRtrucks do not have a time delay start function.
Setting is carried out via the driver's display. It is only
possible to set a start time when the truck is stationary.
(Refer to the "Display" section for information about
how the display works.)
1 Check that the combustion air and exhaust openings
are not blocked.
2 Open the panel vents
Note!
The heater can be used as a
supplement for cold starts, to raise
the cab temperature faster.
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