Service Manual

Table Of Contents
627333-A 5-13
HVAC
HVAC SYSTEM
FIG. 2: HVAC system is located under operator seat.
HVAC unit (1) contains components of heating,
ventilation and air conditioning systems:
Electronic controls
Cab pressurization
Cab airflow moisture removal (defrost)
Cab airflow circulation
Cab airflow heating
Cab airflow cooling
Electronic HVAC Controls
Unit is equipped with an electronic control using a
control module to provide:
Automatic temperature control
Automatic fan control
•LED display
On-board diagnostics
Start-up memory
Display for outside air temperature
Pressurizing Cab
HVAC is used to provide positive air pressure in cab to
prevent unfiltered air from entering.
Removing Moisture from Cab Airflow
HVAC system uses air conditioning to condense
moisture in air. If necessary, air temperature can be
changed by heating system. Moisture condensed is
collected as a liquid and drained.
Circulation of Cab Airflow
HVAC needs airflow to work properly, with operator
controlling direction and amount of airflow.
Heating Cab Airflow
Air circulates by heater core to heat cab air and coolant
is circulated through core.
Cooling Cab Airflow
Air circulates by evaporator core to cool cab air.
Evaporator is cooled by refrigerant, circulated in air
conditioning system located in HVAC unit.
Air conditioning system is a closed loop circuit using
pressure changes of refrigerant to cool cab.
FIG. 2
M112703001
1