Carrier X4 7300 Operation & Service Manual page 86

ProductShield Econo - Go to Continuous Opera-
tion.
When the unit is set for Start/Stop, ProductShield
Econo allows the unit to run in Continuous Operation
when:
• ProductShield Econo configuration is set to GO
TO CONTINUOUS AND
• The unit has run in Start/Stop Operation for a
minimum of 15 minutes OR the MINIMUM RUN
TIME Functional Parameter setting (whichever
time is longer) AND
• The ambient temperature falls outside the pre-
programmed temperature range AND
• The unit is not already running in ProductShield
Winter. (Refer to Section c.)
Once the control system detects that the above criteria
have been met, the unit will switch from Start/Stop to
Continuous Operation for a minimum of 30 minutes.
After 30 minutes the unit will return to Start/Stop if the
ambient temperature enters the pre-programmed tem-
perature range. While the unit is running, the FRESH-
PROTECT Functional Parameter settings will be
effective.
NOTE
Delta -t logic is not used or available when
ProductShield Econo - Go To Continuous is
active.
ProductShield Econo: Go To Continuous 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 Econo Continuous Opera-
tion.
Example 2 If the Minimum is set to 0°F (-17.8°C) and
the Maximum is set to OFF and the ambient air tem-
perature falls below 0°F (-17.8°C), the unit operation
can change to Econo Continuous Operation.
Example 3 If the Minimum is set to OFF and the Max-
imum is set to 90°F (32.2°C) and the ambient air tem-
perature falls above 90°F (32.2°C), the unit operation
can change to Econo Continuous Operation.
Example 4 If both the Minimum and Maximum are set
to OFF, ProductShield Econo: Go To Continuous can
not operate as there is no range for the ambient to fall
outside of.
b. ProductShield: High Air
ProductShield High Air allows the control system to
automatically switch the engine from low speed to high
speed, and thereby provide high evaporator air flow.
This allows maximum product protection when certain
conditions are met while providing for power savings
when High Air is not required.
Operation in High Air is controlled by four Configura-
tions; PRODUCTSHIELD HIGH AIR, HIGH AIR MINI-
M U M T E M P E R AT U R E , H I G H A I R M A X I M U M
TEMPERATURE and HIGH AIR DELTA-T.
• The PRODUCT SHIELD HIGH AIR Configura-
tion may be set to OFF or ON. ProductShield
High Air is only active when the Configuration is
set to ON.
• The High Air ambient air temperature range is
defined by the HIGH AIR MAXIMUM TEMPERA-
TURE Configuration setting and the HIGH AIR
MINIMUM TEMPERATURE Configuration set-
ting. When a value is entered for both of 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 TEMPERA-
TURE Configuration is set for a value and High
Air Minimum Temperature Configuration is set to
OFF, the control system 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 Temperature Configuration is set to
OFF, the control system will switch to high speed
operation when the ambient temperature is
below the setting.
• When both the HIGH AIR MINIMUM TEMPERA-
TURE Configuration and the HIGH AIR MAXI-
MUM TEMPERATURE Configuration 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 control system may switch to
High Speed.
Once the control system determines that the pre-pro-
grammed 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 min-
utes. The original activation conditions must then be
met in order for the unit to return to high air.
c. ProductShield: Winter
When the unit is set for Start/Stop operation, Product-
Shield Winter allows it to switch to Continuous Opera-
tion when the ambient temperature falls below the pre-
programmed temperature. This helps protect the unit
from the possibility of cold weather issues.
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