6000
5000
z
O 4ooo
0c
r_ 3000
I.L,
z
OO 2000
LLI
O
z 1000
<
CO2 SENSOR MAX RANGE SETTING
1000 ppm
_1100 ppm
2 3 4 5 6 7 8
DAMPER VOLTAGE FOR MAX VENTILATION RATE
Fig. 23 -- 002 Sensor Maximum Range Setting
Exhaust Set Point Adjustment -- The exhaust set point will
determine when the exhaust fan runs based on damper position
(if accessory power exhaust is installed). The set point is modi-
fied with the Exhaust Fan Set Point (EXH SET) potentiometel:
The set point represents the damper position above which the
exhaust fans will be turned on. When thele is a call for exhaust,
the EconoMiSer IV controller provides a 45 _+15 second delay
before exhaust fan activation to allow the dampers to open.
This delay allows the dalnper to reach the appropriate position
to avoid unnecessary fan overload.
Minimum Position Control -- There is a minimum damper
position potentiometer on the EconoMiSer IV controllel: See
Fig. 21. The minimum dalnper position mainttdns the mini-
mum airflow into the building during the occupied period.
When using demand ventilation, the minimum damper po-
sition replesents the minimum ventilation position for VOC
(volatile organic compounds) 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
occupied ventilation position. The maximum demand ventila-
tion position should be turned liflly clockwise.
Adjust the minimum position potentiometer to allow the
minimum amount of outdoor air, as requiled 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:
(To x OA) + (TR x RA) = TM
To = Outdoor-Air Temperatme
OA = Percent of Outdoor Air
TR = Return-Air Temperature
RA = Percent of Return Air
TM = Mixed-Air Temperature
As an exmnple, if local codes require 10% outdoor air
during occupied conditions, outdoor-air temperature is
60 IF.and return-air temperature is 75 IF.
(60 x. 10) + (75 x .90) = 73.5 F
2. Disconnect the mixed-air sensor from terminals T and
TI.
3. Ensure that the factory-installed jumper is in place across
terminals P and PI. If lemote damper positioning is being
used, make sure that the terminals are wired according to
Fig. 18 and that the minimum position potentiometer is
turned fully clockwise.
4. Connect 24 vac across terminals TR and TRI.
5. Carefully adjust the minimum position potentiometer
until the measured mixed air temperature matches the cal-
culated v_due.
6. Reconnect the mixed air sensor to termin_ds T and TI.
Remote control of the EconoMiSer IV damper is desirable
when requiring additional temporary ventilation. If a field-
supplied remote potentiometer (Honeywell p_ut number
$963B1128) is wired to file EconoMiSer IV controller, the
minimum 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 PI terminals on the
EconoMiSer IV controllel: Wire file field-supplied potentiome-
ter to the P and PI terminals on the EconoMiSer IV controllel:
See Fig. 20.
Damper Movement -- When the EconoMiSer IV board re-
ceives initial power, it can take the damper up to 21/2 minutes
befole it begins to position itself. After the initial positioning,
subsequent changes to damper position will take up to 30 sec-
onds to initiate. Dmnper movement from lifll open to full
closed (or vice versa) takes 21/2 minutes.
Thermostats -- The EconoMiSer IV control works with con-
ventional thermostats that have a YI (cool stage 1), Y2 (cool
stage 2), WI (heat stage 1), W2 (heat stage 2), and G (fan). The
EconoMiSer IV control does not support space temperature
sensors. Connections me made at the thermostat terminal con-
nection board located in file main control box.
Pressure Drop -- See Fig. 24 and 25 for EconoMiSer IV pres-
sure drop. Evaporator fan may need to be adjusted.
Demand Control Ventilation(DCV) -- When using the
EconoMiSer IV for demand control ventilation, there me some
equipment selection criteria which should be considered. When
selecting the heat capacity and cool capacity of the equipment,
file maximum ventilation rate must be ev_duated for design
conditions. The maximum damper position must be calculated
to provide the desired fresh all:
Typically the maximum ventilation rate will be about 5 to
10% more than the typical cfm lequiled 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
occupancy, and equipment that cannot exceed the required
ventilation rate at design conditions. Exceeding file required
ventilation rate means the equipment can condition air at a
maximum ventilation rate that is greater than file required
ventilation rate for maximum occupancy. A proportional-
anticipatory strategy will cause file fi'esh air supplied to
increase as file room CO2 level increases even though the CO2
set point has not been reached. By the time the CO2 level
reaches the set point, the damper will be at maximum ventila-
tion and should maintain the set point.
In order to have the CO2 sensor control the economizer
damper in this mannel: first determine the damper voltage out-
put for minimum or base ventilation. Base ventilation is the
ventilation required to remove contaminants during unoccu-
pied periods. The following equation may be used to determine
the percent of outside air entering the building for a given
damper position. For best results there should be at least a
10 degree difference in outside and return-air temperatures.
(To x OA) + (TR x RA) = rim
To = Outdoor-Air Temperature
OA = Percent of Outdoor Air
TR = Return-Air Tempemtme
RA = Percent of Return Air
TM = Mixed-Air Temperature
17
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