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these configurations, the unit will enter High Air when ambient temperature is above the high setting or
below the low setting.
• When the High Air Maximum Temperature Configuration is set for a value and High Air Minimum Tempera-
ture Configuration is set to OFF, the microprocessor will switch to high speed operation when the ambient
temperature is above the setting.
• When the High Air Minimum Temperature Configuration is set for a value and High Air Maximum Tempera-
ture Configuration is set to OFF, the microprocessor will switch to high speed operation when the ambient
temperature is below the setting.
• When both the High Air Minimum Temperature Configuration and the High Air Maximum Temperature Con-
figuration are set to OFF, ProductShield High Air is not active.
• If a value is entered in the High Air Delta-T Configuration, the delta-t must be above the value before the
microprocessor may switch to High Speed.
Once the microprocessor determines that the pre-programmed criteria have been met, the unit will switch
to High Air. The unit will continue to operate in High Air for a minimum of 30 minutes. After 30 minutes the
unit will return to normal operation if the ambient temperature falls inside the pre-programmed temperature
range by ±3.6°F (±2°C).
If the unit shuts down in Auto Start/Stop during High Air, it will not be in High Air when it restarts and will
return to normal operation for a minimum of 15 minutes. The original activation conditions must then be
met in order for the unit to return to high air.
ProductShield High Air Examples
• Example 1: If the Minimum is set to 0°F (-17.8°C) and the Maximum is set to 90°F (32.2°C) and the
ambient air temperature falls outside these temperatures, the unit operation can change to High Air
Operation.
• Example 2: If the Minimum is set to 0°F (-17.8°C) and the Maximum is set to OFF and the ambient air
temperature falls below 0°F (-17.8°C), the unit operation can change to High Air Operation.
• Example 3: If the Minimum is set to OFF and the Maximum is set to 90°F (32.2°C) and the ambient air
temperature falls above 90°F (32.2°C), the unit operation can change to High Air Operation.
• Example 4: If both the Minimum and Maximum are set to OFF, ProductShield High Air can not operate
as there is no range for the ambient to fall outside of.
4.9.3.3 ProductShield Winter
When the unit is set for Start/Stop operation, ProductShield Winter allows it to switch to Continuous Oper-
ation when the ambient temperature falls below the pre-programmed temperature. This helps protect the
unit from the possibility of cold weather issues.
Once the microprocessor detects that the ambient temperature has dropped below the pre-programmed
temperature, the unit will switch into ProductShield Winter which will force the unit to operate in Continuous
Operation. The unit will continue to operate in Continuous Operation for a minimum of 30 minutes. After 30
minutes, the unit will return to auto Start/Stop if the ambient temperature has risen above the pre-pro-
grammed ProductShield Winter temperature.
NOTE
All of the ProductShield settings may be viewed in the Data List (Refer to Section 3.15). for units with
IntelliSets, the Data List will reflect the ProductShield settings for the IntelliSet that is currently active.
4.10 Preprogrammed Software Overrides
4.10.1 High Discharge Temperature
The control system monitors the signal provided by the compressor discharge temperature sensor. If compressor
temperature rises to the limit, the system will enter Liquid Injection mode. In this mode the normally closed liquid
injection valve (LIV) will be opened to allow flow of refrigerant into the economizer connection to cool the compres-
sor.
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