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ACQUAINTANCE WITH TRACTOR 
C140 G121 C142 
CONTROL OF AIR CIRCULATION IN 
CAB (D) 
a - surrounding (outer ) air is sucked 
through filters into the cab - air suc-
tion from the cab is closed. 
b - air is sucked from the cab space and 
again blown into the cab (inner air re-
circulation for fast temperature adap-
tation in cab). 
In this position the air inlet from 
outside of the cab is fully closed 
and in the cab no overpressure, 
which prevents penetration of 
non-filtered air into the cab, is 
created!  
Use this position of the control 
only for urgently necessary time! 
RIGHT FUNCTION OF HEATING AND 
AIR-CONDITIONING SYSTEM 
It is necessary to create overpressure in 
the cab for proper function of heating or 
air-conditioning. Therefore we recom-
mend to shut all windows, doors and cab 
roof cover. 
 
 
 
 
 
 
 
 
 
 
 
FAST HEATING THE CAB SPACE 
Process in the following way: 
1 - Turn the control of the heating valve 
(A) to the right-hand position (heating 
valve fully open). 
2 - Set the control of air circulation in the 
cab (D) to the position of inner re-
circulation. 
3 - Choose the desired blower speed 
(position 1, 2, 3) by the blower switch 
(B). 
4 - Set outlets to desired angle to avoid 
direct blowing to persons in the cab. 
5 - Switch over the control lever of the 
heating valve (A) to the left-hand po-
sition.