Airstream Cumberland EXPERT LA, User Manual

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6.3.3 Curtain Compensation
The controller can slightly adjust opening of the
curtains as a function of outside temperature: as
the outside temperature increases, the controller
increases the opening time of the curtains. As a
result, curtains open faster when the outside tem-
perature gets warm. Likewise, when the outside
temperature gets cold the controller increases the
closing time of the curtains. This compensation is
optional. To use it, enable the curtain compensa-
tion in the Installation Setup (section 4.5). Then,
set the outside temperature set point (section 5.1).
When temperature rises:
When the curtain opens, the controller increases
the curtain's On Time by 4% for every 1°F (0.6°C)
in the compensation interval (i.e. an interval of 3°F
means a 12% increase). The curtain's Off Time is
decreased by the same amount.
When temperature falls:
When the curtain closes, the controller increases
the curtain's On Time by 4% for every 1°F (0.6°C)
in the compensation interval (i.e. an interval of 3°F
means a 12% increase). The curtain's Off Time is
decreased by the same amount.
6.3.4 Stopping Fans in Natural Vent.
Whisker switches
are used to stop some on/off and
variable-speed fan outputs when the controller is in
natural ventilation. These switches tell when the
curtains are sufficiently opened.
When temperature rises (point A on the graphic):
The controller gradually opens the curtain as tem-
perature rises. It can also disable a chosen selec-
tion of fans when the curtain is sufficiently opened
(when the curtain has reached its whisker switch).
When temperature falls (point B on the graphic):
At point B, the curtain is already opened and the
fans are stopped. The controller gradually closes
the curtain as temperature falls. The controller re-
starts the fans when the curtain closes and releases
its whisker switch.
Security:
If the temperature drops suddenly or if
the whisker switch is defective, the controller au-
tomatically restarts the fans when the tempera-
ture falls 5°F (3°C) below the lowest curtain's clos-
ing temperature. When this situation occurs, a de-
fective whisker switch alarm is posted to the alarm
log.
Refer to section 4.8 to select what fan
relays must turn off in natural ventilation.
Current
outside T° Outside T°
set point
Compensation interval
Temp.
Current
outside T° Outside T°
set point
Compensation interval
Temp.
ON
OFF
ON
OFF
CURTAIN
STATUS
FAN
OUTPUT
The curtain
closes according
to a timer
The curtain
opens according
to a timer
Room T°
Room T°
A B
The fans restart
when the Whisker
switch is released The curtain has reached
the Whisker switch:
the fans turn off.
Fan Shutoff
in Natural Vent.
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6.3.5 Purge
The purge function allows opening natural
ventilation curtains on a short period of time
to purge the air continuously.
Principle of operation
When a purge cycle starts, both curtains
open during their respective Purge Move
Time . They then stay still during the Purge
Time . When this delay has elapsed, both
curtains return to their initial position until
the beginning of the next purge cycle.
Frequency of the purge cycles
The frequency of purge cycles is deter-
mined by the Purge Cycle Time. A new
purge cycle time after that time delay has
elapsed.
Settings
Select:
Main menu
Start/Stop*
Natural**
Purge***
* A password may be required to access this menu.
** Accessible if at least 1 natural ventilation curtain is enabled
in the Installation Setup (section 4.5).
*** Accessible if the purge option is enabled in the Installation
Setup (section 4.5).
• Set the following parameters:
Purge Time
Once they are opened, curtains stay still dur-
ing this amount of time before returning to
their initial position. Set the purge time to
the desired value.
Purge Cycle
This the amount of time that separates two
purge cycles. The cycle includes the Purge
Move Time (sec. 6.3.2) and the Purge Time .
Set the purge cycle time to the desired value.
Purge cycles are not performed while
the controller is in tunnel ventilation.
Refer to section 6.3.2 to set the amount
of time each curtain need to open
during a purge cycle (Purge Move Time).
Curtain
position
Time
Initial
position
Purge
Move
Time
Purge
Time
Purge Cycle
Purge
Move
Time
Purge Cycles
Main menu
Start/Stop
Natural
Purge
Purge Settings
Purge Time 15 sec
Purge Cycle 180 min