JOHNSON CONTROLS
138
FORM 145.05-NOM7
ISSUE DATE: 10/31/2019
SECTION 5 – SEQUENCE OF OPERATION
• When the economizer becomes active, the position
of the dampers are controlled by the ECONOMIZ-
ER PI logic and can move the dampers beyond the
Active Ventilation Minimum Position; however,
the ECONOMIZER PI logic can never close the
dampers less than the Active Ventilation Minimum
Position.
2-Position Damper
Required Program Values
• OPTIONS key, VENTILATION subsection:
“DAMPER HARDWARE” must be set to 2-PO-
SITION
• PROGRAM key, VENTILATION subsection:
“VENTILATION SYSTEM”
must be set to
USER ENABLED
Sequence of Operation
The analog output to the Outdoor damper is 10V when
the Ventilation System Status is active. The analog
output to the Outdoor damper is 0V when the Ventila-
tion System Status is inactive. The amount of outdoor
air is set by adjusting the damper linkage manually.
Fixed Minimum
Required Program Values
• OPTIONS key VENTILATION subsection:
“DAMPER HARDWARE”
must be set to STAN-
DARD
• PROGRAM key, VENTILATION subsection:
“VENTILATION SYSTEM”
must be set to
USER ENABLED
• SETPOINTS key, VENTILATION subsection:
“OA DAMPER MINIMUM POSITION”
and “OA
DAMPER MAXIMUM POSITION”
must be set
Sequence of Operation
On units configured with the UNIT TYPE set to CON-
STANT VOLUME, the damper minimum position
must be programmed using:
• SETPOINTS key, VENTILATION subsection:
“OA DAMPER MINIMUM POSITION”
On units configured with the UNIT TYPE set to VARI-
ABLE AIR VOLUME or FLEXSYS, the minimum po-
sition varies between the “OA DAMPER MINIMUM
POSITION” and “OA DAMPER MAXIMUM POSI-
TION” based on the speed of the VFD Supply Fan. As
the fan speed decreases, the damper position increases.
DIRTY FILTER SWITCH
The unit can be ordered with a dirty filter switch in-
stalled to monitor the pressure drop across the filters.
The 24VAC binary input to the Unit Controller can be
found at connector J13 – terminal 4.
The following parameter must be programmed into the
Unit Controller:
• OPTIONS key, UNIT DATA subsection: “DIRTY
FILTER SWITCH” must be set to INSTALLED
Sequence of Operation
When the pressure drop across the filters exceeds the
setting of the switch for 1 minute, the switch closes,
sending a 24VAC signal to the Unit Controller. The
Dirty Filter Switch is field adjustable from 0.8 to 4.0
inches Water Column ("W.C.).
When the 24VAC input is received, the Unit Controller
initiates a “WRN DIRTY FILTER.” If the dirty filter
switch opens for 1 minute, the warning is removed.
During the time the warning is active, the unit contin-
ues normal operation.
Set the dirty filter switch to a point that indicates the
filters need to be changed. This is done on startup or
after the filters have become dirty enough to select a
setpoint at which they need to be changed.
FLEXSYS
™
OPERATION
Series LSWU units can be configured for FlexSys op-
eration. FlexSys operation is the use of an underfloor
plenum to provide conditioned air to a building. Since
the conditioned air is delivered up from the floor, the
operation differs from that of a typical VAV system.
Please review these sections thoroughly before pro-
ceeding with unit setup, start-up, and operation.
The design of a FlexSys system is critical to the proper
operation of the LSWU unit. Please review the follow-
ing areas that create issues with the proper operation of
a FlexSys system/unit.
• Plenum Integrity: “If you make a hole, seal a
hole.” The underfloor plenum must be completely
sealed from air leaking out.
• Open Plenum Returns: It is highly recommended
that returns be ducted to every room. This allows
the warmer return air to properly mix and be at the
proper temperature returning to the unit.
