Page 6
Lotus Service Notes Section PN
Ambient air collected from the top of the intake duct, ahead of the engine radiator, is fed via an insulated
fibreform duct to a pollen filter mounted at the intake to the HVAC unit, within which the airflow is divided towards
the inner and outer sides of the two blower fans. Air enters the fan drums axially and is centrifuged outwards to
be directed into the evaporator chamber. A second intake duct collects air from the cabin interior via a central
aperture in the footwell toeboard, from which the air flows through a duct formed in the lower section of the
HVAC unit and into the fan chamber in a similar manner to the ambient flow. Electrical resistors used in the fan
speed circuitry are cooled by the incoming airflow stream. The fresh air intake may be closed off at the driver's
request by an electrically operated flap at the top of the unit, which closes or fully opens the ambient air intake.
The re-circulation intake is open at all times.
All air exiting the fan chamber is directed through the evaporator, whether or not a.c. is selected, and is then
divided between routes flowing either past, or through the heater matrix by an electrically operated air blender
flap, the position of which is determined by the temperature selector knob. Blended air then leaves the top rear
of the HVAC unit and enters the Air Distribution Unit (ADU) which passes beneath the base of the windscreen
and is secured to the top of the footwells. A part cylindrical rotary mask on a horizontal axis, controls the airflow
exiting the ADU into a top mounted port for the windscreen vents, an adjacent port for the face level vents, and,
via a port in each end plate of the mask, to outlets supplying a duct in the top of the passenger footwell, and
through the inboard side of the pedal box. The rotation of the mask is driven by a stepper motor (common with
the air intake and air blender actuators) mounted on the left hand side of the ADU.
Interior Climate Controls
The interior climate control panel is located on the centre console and consists of three rotary control
knobs, for air distribution, temperature and fan speed, and four button switches, for air conditioning, demist,
air re-circulation and heated rear screen. When the sidelamps are switched on, the rotary control graphics are
backlit white and red/blue by an electro-luminescent panel, with red lit pips in the knobs to indicate their position.
The button switches are backlit red with ignition or sidelamps switched on, and will light up brightly (HRS and
demist in amber) when activated. Press the switch a second time to switch off. Climate control functionality
requires the ignition to be on, and for refrigeration and heat production, the engine needs to be running.
Distribution Control
This rotary control is positioned at the top of the HVAC panel and allows a choice of air distribution from
the various outlet vents. There are 5 designated positions with corresponding symbols, although there is a
progressive transition from each airflow mode to the next, allowing a preferred balance to be attained.
Face level vents
To face level vent
ducting in underside
of fascia top panel
Air distribution unit
Airow from
HVAC unit
To Next Page
Loading...
