Lotus Elise Service Notes page 440

Lotus Service Notes Section XA
PF.1 - GENERAL DESCRIPTION
The principal components of the heater/ventilation system comprise a heater matrix unit, incorporating
an air blend flap, a blower fan, a diverter flap assembly, and four fascia outlet vents. The system provides
heated or ambient air to the fascia vents or footwells, via a simple 2-slider control on the fascia, together with
a four speed blower fan selector switch. Airflow from each of the fascia outlet vents may be individually
adjusted for volume and direction by direct manipulation of the vent, and may be optimised for either wind-
screen demisting or face level ventilation.
Air for the ventilation system is taken from the radiator air intake duct, via open ends in two of the 'crush
tubes' in the composite crash structure bonded to the front of the chassis. A pair of holes in the chassis front
crossmember mate with these tubes and admit air into the heater unit on either side of the heater matrix. The
heater matrix is a water/air heat exchanger mounted vertically in a plastic moulding housed in the space
between the front ends of the chassis rails in the front services compartment, and is fed with engine coolant at
all times (no water valve is used) from the cylinder head outlet pipe. Water returns to the engine via a water rail
running around the back and left hand sides of the engine. Water is carried from and to the engine bay, by
aluminium pipes clipped to the outboard sides of the chassis side rails.
Ambient air from radiator air intake
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