24
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 supply air temperature matches the
calculated value.
6. Reconnect the mixed air sensor to terminals T and T1.
Remote control of the EconoMi$er IV damper is desirable
when requiring additional temporary ventilation. If a
field-supplied remote potentiometer (Honeywell part number
S963B1128) is wired to the EconoMi$er IV controller, the
minimum position of the damper can be controlled from a re-
mote location.
To control the minimum damper position remotely, remove
the factory-installed jumper on the P and P1 terminals on the
EconoMi$er IV controller. Wire the field-supplied potentiome-
ter to the P and P1 terminals on the EconoMi$er IV controller.
See Fig. 41.
Damper Movement — Damper movement from full open to
full closed (or vice versa) takes 2
1
/
2
minutes.
Thermostats — The EconoMi$er IV control works with con-
ventional thermostats that have a Y1 (cool stage 1), Y2 (cool
stage 2), W1 (heat stage 1), W2 (heat stage 2), and G (fan). The
EconoMi$er IV 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
the EconoMi$er IV control is occupied mode. Occupied status
is provided by the black jumper from terminal TR to terminal
N. When unoccupied mode is desired, install a field-supplied
timeclock function in place of the jumper between TR and N.
See Fig. 31. When the timeclock contacts are closed, the
EconoMi$er IV control will be in occupied mode. When the
timeclock contacts are open (removing the 24-v signal from
terminal N), the EconoMi$er IV will be in unoccupied mode.
Demand Controlled Ventilation (DCV) — When using the
EconoMi$er IV 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 nor-
mal 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
level increases even though the CO
2
set point has not been
reached. By the time the CO
2
level reaches the set point, the
damper will be at maximum ventilation and should maintain
the set point.
In order to have the CO
2
sensor control the economizer
damper in this manner, 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.
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
Once base ventilation has been determined, set the mini-
mum damper position potentiometer to the correct position.
The same equation can be used to determine the occupied or
maximum ventilation rate to the building. For example, an out-
put of 3.6 volts to the actuator provides a base ventilation rate
of 5% and an output of 6.7 volts provides the maximum venti-
lation rate of 20% (or base plus 15 cfm per person). Use Fig. 42
to determine the maximum setting of the CO
2
sensor. For ex-
ample, a 1100 ppm set point relates to a 15 cfm per person de-
sign. Use the 1100 ppm curve on Fig. 42 to find the point when
the CO
2
sensor output will be 6.7 volts. Line up the point on the
graph with the left side of the chart to determine that the range
configuration for the CO
2
sensor should be 1800 ppm. The
EconoMi$er IV controller will output the 6.7 volts from the
CO
2
sensor to the actuator when the CO
2
concentration in the
space is at 1100 ppm. The DCV set point may be left at 2 volts
since the CO
2
sensor voltage will be ignored by the
EconoMi$er IV controller until it rises above the 3.6 volt set-
ting of the minimum position potentiometer.
Once the fully occupied damper position has been deter-
mined, set the maximum damper demand control ventilation
potentiometer to this position. Do not set to the maximum posi-
tion as this can result in over-ventilation to the space and poten-
tial high-humidity levels.
CO
2
Sensor Configuration — The CO
2
sensor has preset
standard voltage settings that can be selected anytime after the
sensor is powered up. See Table 8.
Use setting 1 or 2 for Carrier equipment. See Table 8.
1. Press Clear and Mode buttons. Hold at least 5 seconds
until the sensor enters the Edit mode.
2. Press Mode twice. The STDSET Menu will appear.
3. Use the Up/Down button to select the preset number. See
Table 8.
4. Press Enter to lock in the selection.
5. Press Mode to exit and resume normal operation.
(T
O
x
OA
) + (TR x
RA
) = T
M
100
100
(T
O
x
OA
) + (TR x
RA
) = T
M
100
100
