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VAV MODULATING HOT WATER REHEAT VARIABLE SPEED FAN
TEMPERATURE CONTROL
When the zone temperature is greater than, or equal to, the cooling temperature setpoint, the controller will
enter the cooling mode. The primary air flow rate will be varied between its
deadband setpoint, and its maximum Flowrate setpoint
the zone at the cooling temperature setpoint.
When the zone temperature falls to the heating setpoint, the controller will enter the heating mode and the
primary air flow rate will be varied between its
(A212), or maximum heating Flowrate setpoint. The modulating hot water reheat valve will then drive open
to maintain the desired heating setpoint.
Typically, the modulating heating valve may be controlled by either
control mode where
options available such as having
heat.
FAN CONTROL
Parallel Variable Fan Speed Option
The variable fan speed will be controlled by modulating
mode only. As more heating is required, the fan speed will increase. See
detail.
Series Variable Fan Speed Option
The variable fan speed will be controlled by modulating AO 15 (default 0
fan will run at a slower speed. As more heating or cooling is required, the fan speed will increase See
Control
on page 58 for more detail.
INPUT / OUTPUT POINTS
VAV Modulating HW Reheat with variable speed fan AO 15 (0
IO POINTS
UI-01
UI-02
UI-03
UI-04
UI-08
DO-09
DO-10
DO-11
DO-12
DO-13
AO-14
AO-15
AO-16
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CBV-2U4-3T(-N) |
drives the hot water valve open, and
DO-11
as first stage modulating heat and AO 15 as second stage modulating
AO-14
Zone Temperature (with optional override button)
Setpoint Adjustment (optional 5K slider)
Discharge Temperature (optional)
CO
, Humidity, or occupancy signal (all optional)
2
Flowrate Sensor
Damper Control (CBV-2U4-3T-N only)
Damper Control (CBV-2U4-3T-N only)
Modulating Heat Control (0 ... 10 Vdc)
Variable Speed Parallel or Series Fan Speed Command (0
Damper Control (CBV-2U4-3T only)
CBV-2U4-3T(-N) Control Sequences
TABPriAirMaxStpt
TabPriAirMinHtgStpt
(A153) and its
or
AO-14
drives it closed. There are additional
DO-12
(default 0
...
10 Vdc). The fan will run in heating
AO-15
Fan Control
...
10 Vdc)
...
DESCRIPTION
TABPriAirDbandStpt
(A210), or
(A211) as required to maintain
TabPriAirMaxHgtStpt
and
in a tri-state
DO-11
DO-12
on page 58 for more
10 Vdc). In deadband mode, the
...
10 Vdc)
Fan
40
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