Carrier Transicold X4 7300, Operation & Service Manual

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62-11637 4–12
The primary time that it is important to determine which
range is to be Range 1 and which is to be Range 2 is
when the ranges overlap each other.
In example 2 (see
Figure 4.5 ), the ranges have been
set to lock all setpoints into Start-Stop, except for a
small range b32° and +42°F (0° and 5.6°C)
where the unit will always operate in Continuous.
Range 1 Minimum Temperature has been set for
+32°F (0°C), and Maximum Temperature of +42°F
(5.6°C). Range 2 has been set for a Minimum Tem-
perature of -22°F (-30°C) and a Maximum Temperature
of +89.6°F (32°C). The unit will switch to Continuous
when the temperature is b32° and +42°F (0°
and 5.6°C) because, when the ranges overlap each
other the Range 1 settings will take priority.
4.10.3 ProductShield
ProductShield is a group of Configurations that work
together to allow improved operating efficiency while
providing customized product protection.
Each ProductShield setting allows the user to select an
ambient temperature range in which to operate. The
Minimum and Maximum range values can be set to
OFF, or the allowed value range.
a. ProductShield: Econo
ProductShield Econo allows the control system to auto-
matically switch from Start/Stop Operation to Continu-
ous Operation or vice versa. This allows maximum
product protection while providing for power savings
when ambient temperature is in the preset range.
While running in ProductShield Econo the FRESHRO-
TECT Functional Parameter settings will be effective.
ProductShield Econo - Go to Start-Stop Operation.
When the unit is set to Continuous Operation, Product-
Shield Econo allows the unit to run in Start/Stop Opera-
tion when:
• The ProductShield Econo Configuration is set to
GO TO S/S AND
• The unit has run in Continuous Operation for a
minimum of either 15 minutes, or the Minimum
Run Time Functional Parameter setting (which-
ever time is longer)
AND
• The ambient temperature falls within the pre-
programmed temperature range AND
• The unit is not already running in ProductShield
Winter. (Refer to Section c.)
The operator can also pre-program a maximum evapo-
rator coil temperature differential (delta-t) between the
return air and supply air temperatures as an additional
criteria for switching to Start/Stop Operation. The unit
must bring the delta-t below this setting before going to
Start/Stop Operation if this option is chosen.
NOTE
In ProductShield Econo: Go to Start/Stop,
the delta-t must be lower than the value
selected in order to enter Start/Stop.
Once the control system detects that the above criteria
have been met, the unit will switch from Continuous
Operation to a Start/Stop Off Cycle for the MINIMUM
OFF TIME Functional Parameter setting. During the
Minimum Off Time, the RESTART OVERRIDE TEM-
PERATURE Functional Parameter setting can cause the
unit to restart to protect the load. After the Minimum Off
Time has expired the unit will return to Continuous Oper-
ation when the return air temperature is more than ±3.6°
F (± 2° C) away from setpoint in the perishable range, or
+3.6°F (+2°C) above setpoint in the frozen range.
When the unit restarts, it will return to Continuous
Operation for a minimum of 15 minutes or the MINI-
MUM RUN TIME Functional Parameter setting, which-
ever time is longer. The original activation conditions
must then be met in order for the unit to return to Prod-
uctShield Econo: Start/Stop.
When ProductShield Econo Maximum Temperature is
set to OFF, and ProductShield Econo Minimum Tem-
perature is set to a temperature, the ambient air tem-
perature will be considered to be “inside the range”
whenever the ambient air temperature is higher than
the Minimum Temperature setting, with no upper limit.
When ProductShield Econo Maximum Temperature is
set to a temperature, and ProductShield Econo Mini-
mum Temperature is set to OFF, the ambient air tem-
perature will be considered to be “inside the range”
whenever the ambient air temperature is lower than the
Maximum Temperature setting, with no lower limit.
When ProductShield Econo Maximum Temperature is
set to OFF, and ProductShield Econo Minimum Tem-
perature is set to OFF, the ambient air temperature will
be considered to be “inside the range” at any ambient
air temperature.
ProductShield Econo: Go To Start/Stop Examples:
The following examples apply in situations where all
other Start/Stop conditions have been met.
Example 1 If the Minimum is set to 30°F (-1.1°C) and
the Maximum is set to 40°F (4.4°C) and the ambient air
temperature falls
between these temperatures, the unit
operation can change to Econo Start/Stop.
Example 2 If the Minimum is set to 30°F (-1.1°C) and
the Maximum is set to OFF and the ambient air tem-
perature is
above 30°F (-1.1°C), the unit operation can
change to Econo Start/Stop.
Example 3 If the Minimum is set to OFF and the Max-
imum is set to 40°F (4.4°C) and the ambient air tem-
perature falls
below 40°F (1.7°C), the unit operation
can change to Econo Start/Stop.
Example 4 If both the Min and the Max are set to OFF,
unit operation can change to Econo Start/Stop at any
ambient temperature.