CBV-2U4-3T(-N) |
Control Sequence Overview
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PRIMARY AIR DAMPER CONTROL
PRIMARY AIRFLOW
The
CBV-2U4-3T(-N)
controller calculates air flow rate setpoints based on the space temperature deviation
from zone setpoint and the duration of deviation. The primary inlet airflow rate is measured and compared to
this control point. Any error greater than the deadband setting will cause the primary air damper to be driven
open or closed as required to reduce the error to within an adjustable Flowrate deadband.
The primary airflow setpoint is read from point
(A197) RO.
PRIMARY AIR SETPOINT MANAGEMENT
The PrimaryAirState is set by the GroupXOccupiedCode or by the on-board Supply Air temp sensor if enabled
The normal and default primary air state is cold air.
Primary Air State: Cold
In normal operation, terminal units are provided with primary air, which is cooler than the zone temperature
setpoint, therefore, the
CBV-2U4-3T(-N)
controller operates with a cold primary air state. In this mode, the
primary air damper opens in direct proportion to the cooling load percentage calculated by the
CBV-2U4-
3T(-N)
controller.
When the primary air state is cold, the primary air volume control is approximated below:
•
Maximum Heat Flowrate Setpoint is
(A212).
o
The Max Heat Flowrate setpoint may be set the same as the Deadband Flowrate Stpt for fan
powered heating boxes, or higher for heating applications without a fan.
•
Minimum Heat Flowrate Setpoint is
o
The Min Heat Flowrate setpoint may be set the same as the Deadband Flowrate Stpt for fan
powered heating boxes, or higher or lower for heating applications without a fan.
•
(A210).
•
Cooling Flowrate Setpoint is
(A211).
0
100
200
300
400
500
600
700
800
900
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70
71
72
73
74
75
76
77
Primary Air Cool
CFM Stpt
Heat
Stpt
DB
Stpt
Cool
Stpt
Summary of Contents for CBV-2U4-3T
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