FlexStat
13
Operation Guide, Rev. L
OA PURGE
= During the 60 minutes prior to
scheduled start time, the outside air
damper will open to this position (0%
default) to perform a purge of the zone. The
value is determined using DCV DAMPER
SETUP.
VENT MODE
= Displays (only) in what ventilation
mode the FlexStat is functioning (see
illustration):
•
Normal
—Typical ventilation during the
occupied period.
•
Pre-purge
—If enabled in the
programming (disabled by default), the
space is ventilated with maximum outside
air for 60 minutes before the occupied start
time. (See Startup.)
•
Startup
—If pre-purge is disabled
(default) and the motion sensor detects
motion during the 20 minutes after
occupied start time, the space is ventilated
with maximum outside air until 20 minutes
after occupied start time.
•
Standby
—After the motion sensor
has not detected motion for 30 minutes,
temperature setpoints are adjusted (down
for heating and up for cooling), and the
outside air damper is closed.
•
Recovery
—After a period in which the
supply fan was off, the space is ventilated
with an increased percentage of outside air
(to compensate for the previous reduced
ventilation).
•
Override
—Ventilation override has been
manually selected from the DCV menu,
and the space is temporarily (30 minutes
default) driven to the full ventilation
position (for maximum design occupancy)
CO2 BASE (PPM)
= The presumed average CO
2
concentration level of outside air at the
building’s location (400 ppm default).
DCV DAMPER SETUP
= A test mode is used to
determine proper outside air damper
position values for OA AREA, OA FULL,
OA MAX, and OA PURGE. The required
airflows for these four positions are
determined by ASHRAE 62.1-2007 section
6.2.6.2. A technician/balancer uses this
menu to set specific damper positions and
measure the resulting airflows. The damper
positions are then correlated to the required
airflows. One hour after the setup mode is
activated, it will return to the default AUTO
setting, or it can be manually set to AUTO
after testing is completed.
FAN MAX OFF (MINS)
= The maximum time (30
default) the supply fan may remain off
during occupied times.
HTG DESIGN TEMP
= The lowest outside air
temperature (20° F default) for which the
building’s heating system is designed.
OA AREA
= The outside air damper position (2%
default) required to provide the outdoor
air rate based on the zone area. This is
based on ASHRAE 62.1-2007 section 6.2.6.2.
(Note that this value represents the damper
position, not the minimum outside air
percentage.) The OA damper shall be at this
position when Space CO2 is at or below
CO2 Base. The value is determined using
DCV DAMPER SETUP.
OA FULL
= The outside air damper position (5%
default) for the OA AREA
plus
the people
occupying the space. The outside air
damper shall be at this position when
Space CO2 is at CO2 SETPT. The value is
determined using DCV DAMPER SETUP.
OA HIGH VENT
= The highest temperature (80°
F default) that would use 100% OA for
recovery.
OA LOW VENT
= The lowest temperature (65° F
default) which would use 100% OA for
recovery. (If outside air temp is between OA
low vent and OA high vent, the outside air
damper will be open 100% during recovery
mode.)
OA MAX
= The maximum allowable % of outside
air damper position (40% default) for
ventilation
(not cooling) purposes. The value
is determined using DCV DAMPER SETUP.
