Air System
The air system consists of two belt-driven fans which provide
the air flow necessary to move cotton from the picking units through
the ducts to the accumulator. When the fan switch on the armrest control
console is moved to the ON position, a signal is sent to the cab control
unit (CAB). The CAB control unit sends a message to the chassis interface
control unit (CIC) which resides in the powershift transmission control
unit (PTP). The PTP monitors engine speed. If engine speed is less
than 1250 rpm (slow idle), the PTP energizes the fan clutch solenoid
and the auxiliary hydraulic power unit engages the fan drive and brings
the fans up to speed. If engine speed is greater than 1250 rpm, the
fans are not engaged and a diagnostic trouble code (DTC) is sent to
the armrest display unit (ADU).
Each fan includes a magnetic speed sensor to monitor the rotor
shaft speed. The sensor output is sent to the CIC unit. Nominal fan
speed is approximately 4330 rpm when the engine is running at fast
idle. If fan speed drops to less than 3600 rpm for more than 2 seconds,
the CIC control unit sends a DTC to the ADU.
Possible causes of low fan speed are:
-
Slipping drive belt
-
Slipping hydraulic clutch
-
Fan engage circuit problems
False or erratic fan speed indications can result from failed
or out of adjustment speed sensors.
| Symptom | Problem | Solution |
|
Picker drops cotton.
| Plugging in suction doors, discharge pipes, or air ducts.
|
Clean and check for
air leaks.
|
|
Plugging in suction doors or ducts.
| Air leakage. |
Check for air leaks
and repair.
|
| |
Fan air pressure low.
|
Inspect condition and
tension of fan belt. Verify that engine is operating at fast idle.
|
| |
Fan rotor vanes plugged.
|
Clean fan rotor vanes.
|
|
Low fan clutch control pressure.
| Oil not warmed up. |
When operating in temperatures
below -12 °C (10 °F), run-in picker 10—15 minutes to
warm up oil.
|
| |
Low on oil.
|
Check for leaks and repair. Fill sump with oil.
|
| |
Plugged oil filter.
|
Replace filter.
|
| |
Pressure regulator valve failure.
|
See your John Deere dealer.
|
|
Low cotton fan speed. Air door on units frequently plugs
with cotton.
| Fan belt tension too low. |
Tighten fan belts. (See
ADJUSTING COTTON FAN BELTS in Air System section.)
|
|
Rigid plastic hose blows off air manifold underneath
cab.
| Missing hose clamps. |
Ensure that air hose
is connected to manifold with two TY22493 clamps and M71217 screws.
|
|
|
DP99999,00006C5-19-20110603
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