Komatsu 830E-AC Shop Manual page 930

COMPONENTS
Figures 4-2 and 4-4 illustrate both the heater system
and air conditioning system parts contained in the
cab mounted enclosure. Refer to Air Conditioning
System in this section for additional information
regarding air conditioning system components, main-
tenance and repair.
Circuit Breakers
Before attempting to troubleshoot the electrical circuit
in the heater enclosure, turn key switch ON and ver-
ify fuse at location FB1-1 (located in the auxiliary
electrical cabinet) is not burned out, and the internal
heater circuit breaker has not opened by verifying 24
VDC is present on the junction block (38, Figure 4-4).
Refer to the electrical schematic for more detailed
information.
N4-4
Relays
Five relays (9, Figure 4-2) control the air dampers, A/
C compressor and the heater valve. All five relays
require 12VDC through the coil which is supplied by
a 24VDC to 12VDC converter (2).
One relay (Relay 1) switches 24 volt current to actu-
ate the A/C compressor clutch. The temperature con-
trol switch, heater valve and the actuator motors all
operate on 12 VDC current.
Heater Core
Heater core (48, Figure 4-4) receives engine coolant
through heater valve (14) when heat is selected. If
temperature control potentiometer (39) is placed in
between the red and blue area, or turned counter-
clockwise to the blue area, coolant flow should be
blocked.
If temperature control potentiometer (39) and heater
valve appear to be working properly, yet no heat is
apparent in heater core (48), the core may be
restricted. Remove and clean or replace the core.
FIGURE 4-2. CAB HEATER/AIR CONDITIONER
1. Enclosure
2. Converter (24 V to 12 V)
3. Water Control (Heater) Valve
4. A/C Refrigerant Hoses
5. Water Outlet (To Engine)
6. Water Inlet (From Engine Water Pump)
7. Evaporator Core
8. Heater Core
9. Relays
Operator Comfort
COMPONENTS
10/06 N04031