FORM 100.50-NOM7 (808)
31
JOHNSON CONTROLS
3
100%
80%
60%
40%
20%
0%
0%
50%
100%
OUTPUT T O VFD
OA
D
MINIM
UM
PO
SI
TI
ON
2
4
3
1
Note:
For units configured for Constant Volume Operation, the OAD
Min Position #2 setting will be ignored and only OAD Min Position
#1 will be used to set the Minimum Position of the outside air
damper.
FIG. 13 – OAD MINIMUM POSITION RESET
LD06562
OAD MIN.
OAD MIN.
CURVE
POSITION #1
POSITION #2
1
10%
2
25% 25%
3
50%
4
80%
Demand Ventilation
Demand Ventilation is a control sequence that can in-
crease or decrease the amount of ventilation introduced
to the building based on ventilation demand. The de-
mand for ventilation will be determined by comparing
the level of CO
2
in the building to the
Demand Venti
-
lation Setpoint
.
The CO
2
level in the building will be
measured by an appropriate CO
2
sensor connected to
the unit.
The Demand Ventilation control sequence will only be
allowed to function if:
• The
IAQ Sensor Enable
setting is set to ON.
• The unit is equipped with an economizer and
Econ-
omizer Enable
= ON.
• The
Airflow Meas Config
configuration is = 0 or 1
(Minimum or 1/4-3/4 configurations not installed
or not enabled).
• Occupancy status is = Occupied.
Demand Ventilation control will operate in both heating
and cooling modes and will increase the position of the
economizer (OA Damper) from the minimum position
or the control positions of economizer or economizer
loading as required to meet the
Demand Ventilation
Setpoint.
Sensor
If all conditions are met, the control will look for an
attached CO
2
sensor at the appropriate AI. The reading
at the AI will be used along with the
IAQ Sensor Span
setting to determine the building CO
2
level.
If the CO
2
level indicated at the AI is out of range, the
controller will interpret the reading as a sensor failure
and generate a Trouble Fault. Demand Ventilation con-
trol sequences will not be allowed if the CO
2
sensor is
determined to be unreliable.
Algorithm
An appropriate algorithm will be used for Demand
Ventilation control. A step and wait algorithm with the
following characteristics is preferred:
• Step size is a function of the difference between
the measured IAQ (CO2) level and the
Demand
Ventilation Setpoint.
• Step time is fixed.
The Demand Ventilation operation will have the fol-
lowing constraints:
The maximum OA Damper position for the Demand
Ventilation operation will be equal to the
(MAX DV
MultiplIer) * (OA Damper Min Pos #1).
Содержание J Series
Страница 85: ...FORM 100 50 NOM7 808 85 JOHNSON CONTROLS 6 ELECTRICAL NOTES AND LEGEND LD13862 ...
Страница 86: ...JOHNSON CONTROLS 86 FORM 100 50 NOM7 808 Service LD13863 CONNECTION DIAGRAM 25 40 TON CV VAV IGV ...
Страница 87: ...FORM 100 50 NOM7 808 87 JOHNSON CONTROLS 6 LD13864 ...
Страница 88: ...JOHNSON CONTROLS 88 FORM 100 50 NOM7 808 Service OPTI CONVERSION TO 25 40 TON LD13854 ...
Страница 89: ...FORM 100 50 NOM7 808 89 JOHNSON CONTROLS 6 LD13865 ELEMENTARY DIAGRAM ALL UNITS ...
Страница 90: ...JOHNSON CONTROLS 90 FORM 100 50 NOM7 808 Service LD13860 ELEMENTARY DIAGRAM GAS HEAT 25 40 TON 230V ...
Страница 91: ...FORM 100 50 NOM7 808 91 JOHNSON CONTROLS 6 ELEMENTARY DIAGRAM GAS HEAT 25 40 TON 575V LD13861 ...