Lennox Core Unit Controller Setup Manual page 31

OPEN DAMPER > TURN BLOWER ON > MIN DAMPER POSITION
BLOWER ON HIGH = .% > MIN DAMPER POSITION BLOWER ON
10.4.5. Motorized Outdoor Air Damper
Set damper position according to "Minimum Damper Position"
section for normal operation, make sure the motorized
outdoor air damper is set correctly in Configuration ID 1,
position 2 needs to be set to M. The damper will open to the
specified position during the occupied time period and close
during the unoccupied time period.
NOTE: When equipped with Motorized Outdoor damper
Air Damper, Prodigy 2.0 provides only Demand
Control Ventilation. Free Cooling/Economizer
function is not available.
10.4.6. Economizer Checkout
The following checkout procedures are completed with unit
energized. Confirm proper operation of the heartbeat LED.
Step 1 will determine whether the economizer is allowing
full damper travel. Use step 2 when the damper does not
respond to step 1.
Steps 3, 4, 5, and 6 checkout the operating modes; checkout
only the mode that applies to the unit being worked on.
CAUTION
Power exhaust fans will be functional. To prevent opera-
tion of power exhaust fans, disconnect power to unit and
then PED jack/plug P/J18.
STEP 1. ECONOMIZER OUTPUT VOLTAGE
The CORE Unit Controller monitors P262 (DPOS) and
operates as reference in Section Damper Diagnostics in
the Prodigy 2.0 (CORE Unit Controller) Application Guide
(Advance Features).
Go to SERVICE > COMPONENT TEST > DAMPER > POSITION >
DAMPER POSITION > DAMPER POSITION: 0.0%
a. The motor will slowly modulate to the closed position.
b. Change DAMPER POSITION ACTUAL to 100.0%.The
motor will slowly modulate to the fully opened position.
c. If the motor does not respond, go to step 2. If the motor
does respond properly, go to the appropriate mode of
operation checkout.
STEP 2. OUTPUT VOLTAGE CHECK
Go to SERVICE > COMPONENT TEST > DAMPER > POSITION >
DAMPER POSITION > DAMPER POSITION: 0.0%
a. Adjust the DAMPER POSITION ACTUAL to 0.0%
position.
b. Measure the voltage on P262 between pin 3 (VOT
damper control) and pin 2 (GND) using pin 1 as common.
Voltage should read approximately 2 VDC.
c. Adjust the DAMPER POSITION ACTUAL to 100.0%
position.
NOTE: Allow approximately 90 seconds for actuator to
react.
d. Measure the voltage between P262 between pin 3 (VOT
damper control) and pin 2 (GND) using pin 1 as common.
LOW = .%
Voltage should read approximately 10 volts DC. If not,
check wiring and trouble shoot system.
STEP 3. SINGLE ENTHALPY OPERATION (ODE)
In the single enthalpy mode, dampers open for free cooling
when the outdoor enthalpy is less than the enthalpy set point
(Parameter 162 - ECON FREECL ENTH SP); dampers will try
to modulate discharge air temperature (RT6) to (Parameter
159 - FREE COOL SUPPLY SP) which has a default setting
of 55.0°F (13°C).
a. Go to SETUP > INSTALL > press SAVE until you get to
the Configuration ID 1, position 2 needs to be set to S for
Economizer Single Enthalpy and press SAVE.
b. To simulate low outdoor enthalpy. Disconnect A7 outdoor
enthalpy sensor jack/plugs J/P104. Connect a 750 ohm
resistor across plug J104-1 and J104-2. J104 is located
in the filter access area.
c. Check all connections and wiring between J104 and the
control.
STEP 4. DUAL ENTHALPY MODE OF OPERATION
In dual enthalpy mode, dampers open for free cooling when
the outdoor air enthalpy is lower than the return air enthalpy
by difference value of (Parameter 163 - ECN FRCL ENTH
OFFST); dampers will modulate discharge air temperature
(RT6) to (Parameter 159 - FREE COOL SUPPLY SP) which
has a default setting of 55.0°F (13°C).
a. Go to SETUP > INSTALL > press NEXT until you get to
the Configuration ID 1 position 2 needs to be set to D for
Economizer Dual Enthalpy and press SAVE if performing
an economizer field-install.
b. Use two resistors to simulate outdoor air enthalpy
suitable.
c. Disconnect A62 return air enthalpy sensor jack/plug
J/P105. Place a 1500 ohm resistor between J105-1 and
J105-3. J/P105 is located in the filter access area.
d. Disconnect A7 outdoor enthalpy sensor jack/plugs J/
P104. Connect a 750 ohm resistor across J104-1 and
J104-2.
STEP 5. ALL TEMPERATURE MODES OF OPERATION
In the Economizer – Temperature mode, the damper opens
for free cooling when the outdoor air temperature is:
• Less than return air temperature by at least a difference
of (Parameter 161 - ECON FRCL TMP OFFST) if
Temperature Offset mode is selected
• Less than (Parameter 160 - ECON FREECL TEMP SP)
In all modes, dampers will try to modulate discharge air
temperature (RT6) to (Parameter 159 - FREE COOL
SUPPLY SP) which has a default setting of 55.0°F (13°C).
Refer to the "Displaying Sensor Inputs" section to read return
air (RT16) and outdoor air (RT17) temperatures. If outdoor
air is not cooler than return air, simulate a colder outdoor
air temperature with a resistor. Select a resistor value that
corresponds to a temperature:
a. Locate RT17 sensor in unit. Disconnect 1/4" quick
connect terminals on wires leading from sensor.
b. Jumper RT17 wires leading back to control with the
appropriate resistor.
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