Heater System
Heater System
GENERAL
- The Impreza's HVAC system uses an integral air conditioning unit with thin-wall, high-performance heater core at the front and evaporator core at the rear. Being compact in size, this unit enables providing sufficient front passenger's legroom while ensuring a high air-distribution efficiency by minimizing air flow resistance in all air passages. Overall, the system can create comfortable interior air conditions quietly and in all seasons by its excellent heating, cooling, ventilating, and defrosting performances.
- There are three ventilation grilles in the dashboard; a trapezoidal grille at the center and round grilles at both sides. The side grilles are rotatable for air flow direction adjustments.
- To ensure adequate ventilation, large-size air outlets are provided behind the side portions of the rear bumper where high-level vacuums are generated during driving.
Air Flow Modes:
AIR FLOW MODES
CONTROL PANEL
- The HVAC control panel is incorporated into the center panel.
- A rear window defogger switch is located in the control panel.
VEHICLES WITH AIR CONDITIONING
- The control panel uses three large-diameter, dial type switches for easy operation and good visual recognition.
1. Air outlet control dial
This switch allows selecting any of the five air flow modes.
2. Fan speed control dial
This switch allows turning on/off the blower and selecting any of the four blower speeds.
3. Temperature control dial
This switch allows adjusting the temperature of air delivered through ventilators steplessly.
4. Rear window defogger switch
This switch activates the rear defogger. When the switch is left on, a timer keeps the defogger activated for 15 minutes and then turns it off automatically.
5. FRESH/RECIRC lever
This lever allows selecting either cabin-air-recirculation or fresh-air-introduction.
6. Air conditioning switch
This switch turns on or off the air conditioning compressor.
HEATER AND COOLING UNIT
- Having an evaporator core at the front and a heater core at the rear, this single unit combines both heating and cooling functions.
- The heater and cooling unit incorporates doors for creating different air flow modes and a door for mixing heated air and outside air.
- The air flow mode switching doors and air mixing door are moved by cables through corresponding linkages.
DESIGN FEATURES FOR EACH AIR FLOW MODE
1. Ventilation (VENT) mode
- The passage leading air from the evaporator to the ventilation outlet (VENT) is made straight to reduce air flow resistance.
- When the air temperature is necessary to be adjusted, heated air is blown at right angles against the flow of cool air from the evaporator. This allows the airs to mix thoroughly.
2. Foot/face (BILEVEL) mode
- Warm and cool air flows are created by structural means, namely, by forming sealing surface for air toward leg area on the heated air passage side and that for air toward the ventilation outlet (VENT) on the cooled air passage side.
To prevent an excessive difference in the temperature between the two air flows, a bypass passage is provided to allow part of heated air to flow toward the ventilation (VENT) outlet.
3. Heating (HEAT) mode
- Warm and cool air flows are created by structural means, namely, by forming sealing surface for air toward leg area on the heated air passage side and that for air toward the defroster (DEF) outlet on the cooled air passage side.
To prevent an excessive difference in the temperature between the two air flows, a bypass passage is provided to allow part of heated air to flow toward the ventilation (VENT) outlet.
- To maintain the passage toward the defroster (DEF) outlet even during the heating mode operation, the door of the passage toward leg area is fully opened to the make the passage also serve as a passage toward the defroster (DEF) outlet.
4. Defroster (DEF) mode
- Air passages are designed in such a way that air flow resistance is minimized and defrosting performance is maximized.
- The air passages toward the defroster (DEF) outlet is long enough to ensure a same airflow rate at all defroster outlets.
BLOWER UNIT
- The blower unit uses a low-noise-type motor.
DUCT
- The ventilation duct and defroster duct are located behind the instrument panel. Both the ducts have been modified in the shape to reduce air flow resistance.
- Defrosting air flow is divided at the center, so that air can flow out evenly through a wide center defroster as well as right and left side defrosters.