Komatsu 830E, Shop Manual

Page: 686 / 783

N4-4 Operator Comfort N04023
HEATER CORE
The heater core (46, Figure 4-4) receives engine
coolant through the heater valve (14) when HEAT is
selected. If the temperature control potentiometer
(37) is placed in between the red and blue area, or
turned counterclockwise to the blue area, coolant
flow should be blocked.
If the selector switch (34) and heater valve appear to
be working properly, yet no heat is apparent in the
heater coil (46), the coil may be restricted. Remove
and clean or replace the coil.
FAN MOTOR AND SPEED CONTROL
Fan speed is controlled by inserting resistor(s) (49 &
50) in series with the supply circuit to the blower
motor to reduce voltage. The number of resistors in
series is determined by the position of the fan speed
selector switch.
At low speed, 3 resistors are used, at medium speed,
1 resistor is used, and for high speed, the full
+24VDC is supplied to the blower motor, bypassing
all resistors.
Test
If the motor (5) does not operate at any of the speed
selections, verify battery voltage is available at the
switches, relay, and circuit breakers (refer to electri-
cal schematic, Section R). If voltage is present, the
motor is probably defective and should be removed
and replaced.
If the motor operates at high speed, but does not
operate at reduced speed, inspect the resistors for
physical damage or an open circuit. Replace resis-
tors as required.
ACTUATORS
Two (2) rotary actuators (8, Figure 4-4) are installed
inside the heater housing and are used to actuate the
flappers for the following:
• Defroster outlet
• Bi-level or floor outlets
A failure to switch one of the above modes of opera-
tion may be caused by a faulty actuator.
Test
Visually inspect the flappers (11, or 43) and linkage
for the function being diagnosed. Make certain the
flapper is not binding or obstructed, preventing
movement from one mode to the other.
Verify voltage (12 volts) is present at the actuator
when the toggle switch is closed or absent when the
toggle switch is opened.
If voltage is proper, disconnect actuator from flapper
and verify actuator force is comparable to a known
(new) actuator. If not, replace with a new actuator.
FILTER
Service
Inlet filters in the heater cover (19) and the cab
access panel need periodic cleaning to prevent
restrictions in air circulation. Restricted filters will
decrease the performance of the heater and air con-
ditioner. The recommended interval for cleaning and
inspection is 250 hours, but in extremely dusty condi-
tions, the filters may need daily service and inspec-
tion, especially the outer panel filter on the cab shell.
The filter elements should be cleaned with water and
dried in a dust free environment before reinstallation.
Replace the filter element every 2000 hours or
sooner if inspection indicates a clogged or damaged
filter.
AIR CONDITIONER COMPONENTS
Components installed in the heater housing, unique
to the air conditioner system, are discussed in Sec-
tion M, "Air Conditioning System" .