Heater/Air Conditioner; Heater Components; Circuit Breakers - Komatsu 930E-2 Shop Manual

HEATER/AIR CONDITIONER

The heater assembly incorporates all the controls nec-
essary for regulating the cab interior temperature;
heated air during cold weather operation, outside air
during mild temperatures and cooled, de-humidified air
during warm weather operation if the optional air con-
ditioning system is installed.
The following information primarily describes the
heater system. Refer to Section M, "Air Conditioning
System" for detailed information concerning the com-
plete air conditioning system operation, repair, and
system recharging instructions.
OPERATION
Heat for the cab is provided by passing coolant from
the engine cooling system through a heater coil. Blow-
ers move air across the heating coil which warms the
air for heating or defrosting.
An engine driven freon compressor passes air condi-
tioning system refrigerant through an evaporator coil
mounted in the same enclosure. The same blowers
used for heating move air across the evaporator to
provide cooled air through the outlet vents.
All heater and air conditioner controls are mounted on
a pod on the face of the enclosure.
N03011 7/98

HEATER COMPONENTS

NOTE: Figures 3-4 and 3-5 illustrate both the heater
system and air conditioning system parts contained in
the cab mounted enclosure. Refer to Section "M" for
additional information regarding air conditioning sys-
tem components, maintenance and repair.

CIRCUIT BREAKERS

Before attempting to troubleshoot the electrical circuit
in the heater enclosure, turn key switch ON and verify
circuit breaker CB31 (located on Power Distribution
Module behind operator's seat) and the internal heater
circuit breaker have not opened by verifying +24VDC
is present on the junction block (24, Figure 3-5).
1. Enclosure
2. Heater Control Module
3. Water Control Valve
4. A/C Freon Hoses
5. Water Outlet (To Engine)
6. Water Inlet (From Engine Water Pump)
7. Evaporator Coil
8. Heater Coil
Cab Components
FIGURE 3-4. CAB HEATER/AIR
CONDITIONER COMPONENTS
N3-3