22
Minimum Position Control
— There is a minimum damper
position potentiometer on the EconoMi$erIV controller. See
Fig. 33. The minimum damper position maintains the mini-
mum airflow into the building during the occupied period.
When using demand ventilation, the minimum damper po-
sition represents the minimum ventilation position for VOC
(volatile organic compound) ventilation requirements. The
maximum demand ventilation position is used for fully occu-
pied ventilation.
When demand ventilation control is not being used, the
minimum position potentiometer should be used to set the oc-
cupied ventilation position. The maximum demand ventilation
position should be turned fully clockwise.
Adjust the minimum position potentiometer to allow the
minimum amount of outdoor air, as required by local codes, to
enter the building. Make minimum position adjustments with
at least 10° F temperature difference between the outdoor and
return-air temperatures.
To determine the minimum position setting, perform the
following procedure:
1. Calculate the appropriate mixed-air temperature using the
following formula:
T
O
= Outdoor-Air Temperature
OA = Percent of Outdoor Air
T
R
= Return-Air Temperature
RA = Percent of Return Air
T
M
= Mixed-Air Temperature
As an example, if local codes require 10% outdoor air
during occupied conditions, outdoor-air temperature is
60 F, and return-air temperature is 75 F.
(60 x .10) + (75 x .90) = 73.5 F
2. Disconnect the supply-air sensor from terminals T and
T1.
3. Ensure that the factory-installed jumper is in place across
terminals P and P1. If remote damper positioning is being
used, make sure that the terminals are wired according to
Fig. 31 and that the minimum position potentiometer is
turned fully clockwise.
4. Connect 24 vac across terminals TR and TR1.
5. Carefully adjust the minimum position potentiometer
until the measured mixed-air temperature matches the
calculated value.
6. Reconnect the supply air sensor to terminals T and T1.
Remote control of the EconoMi$erIV damper is desirable
when requiring additional temporary ventilation. If a
field-supplied remote potentiometer (Honeywell part number
S963B1128) is wired to the EconoMi$erIV controller, the min-
imum position of the damper can be controlled from a remote
location.
To control the minimum damper position remotely, remove
the factory-installed jumper on the P and P1 terminals on the
EconoMi$erIV controller. Wire the field-supplied potentiome-
ter to the P and P1 terminals on the EconoMi$erIV controller.
See Fig. 37.
Damper Movement
— Damper movement from full open to
full closed (or vice versa) takes 2
1
/
2
minutes.
Thermostats
— The EconoMi$erIV control works with con-
ventional thermostats that have a Y1 (cool stage 1), Y2 (cool
stage 2), W1 (heat stage 1), W2 (heat stage 2), and G (fan). The
EconoMi$erIV control does not support space temperature
sensors. Connections are made at the thermostat terminal con-
nection board located in the main control box.
Occupancy Control
— The factory default configuration for
EconoMi$erIV control is occupied mode. This is implemented
by the RED jumper at TB2-9 to TB2-10. When unoccupied
mode is desired, remove the RED jumper and install a field-
supplied timeclock function between TB2-9 and TB2-10.
When the timeclock contacts are open, the unit control will be
in unoccupied mode; when the contacts are closed, the unit
control will be in occupied mode.
Demand Controlled Ventilation (DCV)
— When using the
EconoMi$erIV for demand controlled ventilation, there are
some equipment selection criteria which should be considered.
When selecting the heat capacity and cool capacity of the
equipment, the maximum ventilation rate must be evaluated for
design conditions. The maximum damper position must be cal-
culated to provide the desired fresh air.
Typically the maximum ventilation rate will be about 5 to
10% more than the typical cfm required per person, using
normal outside air design criteria.
A proportional anticipatory strategy should be taken with
the following conditions: a zone with a large area, varied occu-
pancy, and equipment that cannot exceed the required ventila-
tion rate at design conditions. Exceeding the required ventila-
tion rate means the equipment can condition air at a maximum
ventilation rate that is greater than the required ventilation rate
for maximum occupancy. A proportional-anticipatory strategy
will cause the fresh air supplied to increase as the room CO
2
(T
O
x
OA
)+(TRx
RA
)=T
M
100 100
TR1
24 Vac
COM
TR
24
Vac
HOT
12
3
4
5
EF
EF1
+
_
P1
T1
P
T
N
EXH
2V 10V
EXH
Set
Set
2V 10V
2V 10V
DCV
DCV
Free
Cool
B
C
A
D
SO+
SR+
SR
SO
AQ1
AQ
DCV
Min
Pos
Open
Max
N1
Fig. 37 — EconoMi$erIV Controller
0
1000
2000
3000
4000
5000
6000
2345678
800 ppm
900 ppm
1000 ppm
1100 ppm
RANGE CONFIGURATION (ppm)
DAMPER VOLTAGE FOR MAX VENTILATION RATE
CO SENSOR MAX RANGE SETTING
2
Fig. 38 — CO
2
Sensor Maximum Range Setting
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