Carrier WeatherMaker 50KCQ A04 Series Service And Maintenance Instructions page 40

duct. The EconoMi$er IV controller compares the outdoor air
enthalpy to the return air enthalpy to determine EconoMi$er IV
use. The controller selects the lower enthalpy air (return or out-
door) for cooling. For example, when the outdoor air has a
lower enthalpy than the return air, the EconoMi$er IV opens to
bring in outdoor air for free cooling.
Replace the standard outside air dry bulb temperature sensor
with the accessory enthalpy sensor in the same mounting loca-
tion. (See Fig. 51.) Mount the return air enthalpy sensor in the
return air duct. (See Fig. 62.) Wiring is provided in the
EconoMi$er IV wiring harness. (See Fig. 51.) The outdoor en-
thalpy changeover set point is set with the outdoor enthalpy set
point potentiometer on the EconoMi$er IV controller. When
using this mode of changeover control, turn the enthalpy set
point potentiometer fully clockwise to the D setting.
Indoor Air Quality (IAQ) Sensor Input
The IAQ input can be used for demand control ventilation con-
trol based on the level of CO
air duct.
Mount the accessory IAQ sensor according to manufacturer
specifications. The IAQ sensor should be wired to the AQ and
AQ1 terminals of the controller. Adjust the DCV potentiome-
ters to correspond to the DCV voltage output of the indoor air
quality sensor at the user-determined set point. (See Fig. 65.)
CO SENSOR MAX RANGE SETTING
2
6000
5000
4000
3000
2000
1000
0
2 3 4
Fig. 65 — CO Sensor Maximum Range Settings
2
If a separate field-supplied transformer is used to power the
IAQ sensor, the sensor must not be grounded or the
EconoMi$er IV control board will be damaged.
When using demand ventilation, the minimum damper position
represents the minimum ventilation position for VOC (volatile or-
ganic compounds) ventilation requirements. The maximum de-
mand ventilation position is used for fully occupied ventilation.
When demand ventilation control is not being used, the mini-
mum position potentiometer should be used to set the occupied
ventilation position. The maximum demand ventilation posi-
tion should be turned fully clockwise.
Exhaust Set Point Adjustment
The exhaust set point will determine when the exhaust fan runs
based on damper position (if accessory power exhaust is in-
stalled). The set point is modified with the Exhaust Fan Set
Point (EXH SET) potentiometer. (See Fig. 59.) The set point
represents the damper position above which the exhaust fans
will be turned on. When there is a call for exhaust, the
EconoMi$er IV controller provides a 45 ± 15 second delay be-
fore exhaust fan activation to allow the dampers to open. This
delay allows the damper to reach the appropriate position to
avoid unnecessary fan overload.
Minimum Position Control
There is a minimum damper position potentiometer on the
EconoMi$er IV controller. (See Fig. 59.) The minimum
measured in the space or return
2
800 ppm
900 ppm
1000 ppm
1100 ppm
5 6 7 8
damper position maintains the minimum airflow into the build-
ing during the occupied period.
When using demand ventilation, the minimum damper position
represents the minimum ventilation position for VOC (volatile
organic compound) ventilation requirements. The maximum de-
mand ventilation position is used for fully occupied ventilation.
When demand ventilation control is not being used, the mini-
mum position potentiometer should be used to set the occupied
ventilation position. The maximum demand ventilation posi-
tion should be turned fully clockwise.
Adjust the minimum position potentiometer to allow the mini-
mum 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 fol-
lowing procedure:
1. Calculate the appropriate mixed air temperature using the
following formula:
OA
(T x )
O
100
T = Outdoor-Air Temperature
O
OA = Percent of Outdoor Air
T = Return-Air Temperature
R
RA = Percent of Return Air
T = Mixed-Air Temperature
M
As an example, if local codes require 10% outdoor air during
occupied conditions, outdoor-air temperature is 60°F, and re-
turn-air temperature is 75°F.
(60 x 0.10) + (75 x 0.90) = 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. 50 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 calcu-
lated value.
6. Reconnect the supply air sensor to terminals T and T1.
Remote control of the EconoMi$er IV damper is desirable
when requiring additional temporary ventilation. If a field-sup-
plied remote potentiometer
S963B1128) is wired to the EconoMi$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. 64.)
Damper Movement
Damper movement from full open to full closed (or vice versa)
takes 2 1 / minutes.
2
Thermostats
The EconoMi$er IV control works with conventional thermo-
stats that have a Y1 (cool stage 1), Y2 (cool stage 2), W1 (heat
stage 1), W2 (heat stage 2), and G (fan). The EconoMi$er IV
control does not support space temperature sensors. Connec-
tions are made at the thermostat terminal connection board lo-
cated in the main control box.
40
RA
+ (T x ) = T
R
100
(Honeywell part
M
number