SL L4-1.9L SOHC VIN 8 (1997)
Housing Assembly HVAC: Description and Operation
HVAC Module
HVAC Module
The HVAC module consists of the recirc motor, the blower motor and fan, the blower motor resistor, the heater core, and the evaporator core. The
operations of these assemblies are controlled by the levers and switches on the HVAC control panel.
Air Distribution
Distribution of the air is controlled by the mode levers and buttons on the control assembly. The various positions of the mode levers and buttons direct
cooled, heated, blended, outside, or inside air through the air ducts. The flow of air during the various modes of operations is as follows:
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Face - Instrument Panel Outlets With a Small Amount of Bleed Air to the Heater
^
Face and Feet - Instrument Panel Outlets, and Floor Outlets
^
Feet - Floor Outlets With a Small Amount of Bleed Air to Defroster
^
Top - Defroster Ducts With a Small Amount of Bleed Air to the Heater
Evaporator Core
The evaporator is a device which cools and dehumidifies the air before it enters the passenger compartment. Low pressure liquid refrigerant flows
through the expansion valve into evaporator. The heat in the air passing through the evaporator core is lost to the cooler surface of the core, thereby
cooling the air. As the process of heat loss from the air to the evaporator core surface is taking place, the moisture (humidity) in the air condenses on the
outside surface of the evaporator core and is drained off as water. Evaporator pipes are now wrapped with mastic for system noise reduction.
