ABB FBVi-2U4-4T - VAV Cooling only Constant Series Speed Fan

FBVi-2U4-4T | FBVI-2U4-4T Contr
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Subject to change without notice
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60
MAN0148 rev 5
VAV COOLING ONLY CONSTANT SERIES SPEED FAN
TEMPERATURE CONTROL
When the zone temperature is greater than the cooling temperature setpoint, the controller will enter
the cooling mode. The primary airflow rate will be varied between its minCoolFlowStpt (A227), and its
maximum Flowrate setpoint maxCoolFlowStpt (A228) as required to maintain the zone at the cooling
temperature setpoint. Once the zone temperature falls below the cooling temperature setpoint, it will
exit the cooling mode.
When the zone temperature is between the cooling and heating temperature setpoints, it will be in
Deadband or Vent Mode. The controller will maintain the minCoolFlowStpt (A227).
When the zone temperature falls below the heating setpoint, the controller will enter the heating mode
and the primary airflow rate will maintain the minCoolFlowStpt (A227). Once the zone temperature
rises above the heating temperature setpoint, it will exit heating mode.
DAMPER CONTROL
Before the series fan is enabled, the damper will close for 60 seconds to prevent the box fan from
running backwards.
SERIES SINGLE SPEED FAN
The fan (DO 13) will operate continuously whenever the unit is in the occupied state, or if there is a
request for heating or cooling. The fan control matrix is as follows:
MODE
COOLING
DEADBAND
HEATING
Occupied
On
On
On
Unoccupied
On
Off
On
Warm-up
N/A
On
On
Standby
On
On
On