jcb JS300 Service Manual page 379

change where the inlet air is drawn in from by moving
a control flap.
– Water valve (Actuator). The PWM module changes
the signal to the Water valve as requested on the
temperature dial on the ATC control panel. This
adjusts the quantity of heater coolant into the heater
core to obtain the correct cab temperature.
– Compressor Drive Clutch. The compressor drive
clutch is in the compressor mounted on the engine.
The compressor drive clutch receives an output
signal from the ATC control panel to control when the
clutch must be engaged or disengaged. This depends
upon what temperature is selected on the ATC control
panel. When the clutch is engaged, a snowflake
symbol is shown in the top right hand corner of the
LCD display. The drive clutch can automatically
disengage if an error occurs in the system and an
error code shows on the LCD display. This is to
prevent the system from more damage.
B-10
Section B - Body and Framework
Heater/Air Conditioning SYSTEM
9813/5100-1
Operation Overview
B-10