22
EXPERT WW rev.12
EXPERT WW
6.3. Natural Ventilation
Curtains
The controller can control 2 natural ventila-
tion curtains. To operate these curtains, the
controller refers to the average temperature
reading of their assigned temperature probes
(see sec. 4.7.3).
6.3.1. Principle of Operation
The controller enters in natural ventilation
when the average temperature of the probes
that are assigned to a curtain reaches the
“Initial Opening Temperature”
of the curtain.
At that moment, the curtain opens during its
“Initial Opening Time”
.
When the natural ventilation mode is on,
the natural ventilation curtain moves in
timer mode: it opens according to its open-
ing cycle
(“Open Time” & “Off Time”)
when the
average temperature rises above its opening
temperature; likewise, it closes according to
its closing cycle
(“Close Time” & “Off Time”)
when the temperature falls below its closing
temperature.
Natural ventilation is disabled when the aver-
age temperature decreases of 5°F (2.8°C)
below the curtain’s closing temperature or
when tunnel ventilation starts (see graph
below).
Transition from tunnel to natural ventilation:
When the temperature decreases below the
start temperature of the first tunnel stage,
the controller opens the curtain continuously
during the
“Continuous Opening Delay”
. When
this delay has elapsed, it starts controlling the
curtain using natural ventilation settings.
Transition from natural to tunnel ventilation:
When the natural ventilation curtain is opened
and the room temperature reaches the start
temperature of the first tunnel stage, the con-
troller waits for the “
Tunnel Close Delay”
then
fully closes the natural ventilation curtain.
Relation between Fan Stages &
Natural Ventilation Curtains
Curtain
Status
ON
ON
OFF
OFF
Set Point
Set Point
Close at
The curtain
closes in timer
mode
The curtain
opens in timer
mode
Open at
Average T° of
the curtain’s
probes
Stage
Activation
First tunnel
stage
Initial
opening T°
Stop
Natural
5°F
Natural
Ventilation
Status
