ECONOMIZER
The Economizer can be a factory installed option or a field installed accessory. If factory installed, refer to the instruc- tions included with the outdoor air hood to complete the assembly. Field installed Economizer accessories include complete instructions for installation.
There are two Economizer options:
1.Down Flow application with barometric relief hood standard.
2.Horizontal Flow application that requires the purchase of a barometric relief hood.
POWER EXHAUST
The Power Exhaust can be a factory installed option or a field installed accessory. If factory installed, refer to the instruc- tions included with the outdoor air hood to complete the assembly. Field installed Power Exhaust accessories include complete instructions for installation.
The Power Exhaust factory installed option is for Down Flow application only.
There are two field installed Power Exhaust accessories:
1.Down Flow application.
2.Horizontal Flow application that requires the purchase of a barometric relief hood.
RAIN HOOD
All of the hood components, including the filters, the gasket- ing and the hardware for assembling, are packaged and located between the condenser coil section and the main unit cabinet, if the unit has factory installed options. If field installed accessories are being installed all parts necessary for the installation comes in the accessory.
ECONOMIZER AND POWER EXHAUST SET POINT ADJUSTMENTS AND INFORMATION
Remove the top rear access panel from the unit. Locate the economizer control module, where the following adjustments will be made.
Extreme care must be exercised in turning all set point, maximum and minimum damper positioning adjustment screws to prevent twisting them off.
MINIMUM POSITION ADJUSTMENT
•Check that the damper blades move smoothly without binding; carefully turn the Minimum Position Adjust screw (found on the damper control module) fully clock- wise and then set the thermostat indoor fan switch to the
ON position and then OFF or energize and
•With the thermostat set to the indoor fan ON position or terminals “R” to “G” energized, turn the Minimum Posi- tion Adjusting screw (located on the damper control module) counterclockwise until the desired minimum damper position has been attained.
ENTHALPY SET POINT ADJUSTMENT
The enthalpy set point may now be set by selecting the desired set point shown in the Enthalpy Set Point Adjustment Figure 20. Adjust as follows:
•For a single enthalpy operation carefully turn the set point adjusting screw (found on the damper control mod- ule) to the "A", "B", "C" or "D" setting corresponding to the lettered curve of the Enthalpy Set Point Adjustment Figure 20.
•For a dual enthalpy operation, carefully turn the set point adjusting screw fully clockwise past the "D" setting.
POWER EXHAUST DAMPER SET POINT (WITH OR WITH- OUT POWER EXHAUST)
•With no power exhaust option, adjust the Exhaust Air Adjustment Screw fully clockwise. This will allow 2nd stage cooling to operate.
•With power exhaust option, each building pressurization requirement will be different. The point at which the power exhaust comes on is determined by the econo- mizer damper position (Percent Open). The Exhaust Air Adjustment Screw should be set at the Percent Open of the economizer damper at which the power exhaust is needed. It can be set from 0 to 100% damper open.
INDOOR AIR QUALITY AQ
Indoor Air Quality (indoor sensor input): Terminal AQ accepts a +2 to +10 Vdc signal with respect to the (AQ1) terminal. When the signal is below it's set point, the actuator is allowed to modulate normally in accordance with the enthalpy and mixed air sensor inputs. When the AQ signal exceeds it's set point setting and there is no call for free cooling, the actuator is proportionately modulated from the 2 to 10 Vdc signal, with 2 Vdc corresponding to full closed and 10 Vdc corresponding to full open. When there is no call for free cooling, the damper position is limited by the IAQ Max damper position setting. When the signal exceeds it's set point (Demand Control Ven- tilation Set Point) setting and there is a call for free cooling, the actuator modulates from the minimum position to the full open position based on the highest call from either the mixed air sensor input or the AQ voltage input.
•Optional CO2 Space Sensor Kit Part # 2AQ04700324
•Optional CO2 Sensor Kit Part # 2AQ04700424 Replace the top rear access panel on the unit.
22 | Unitary Products Group |