Carrier TRANSICOLD VECTOR 8100 Operation & Service Manual Download

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3. Minimum Off Time has expired

The MINIMUM OFF TIME Functional Parameter setting allows the unit to remain off for extended periods of time,
maximizing power economy. The unit may not be restarted until the MINIMUM OFF TIME has expired and the
compartment temperature is greater than the PERISHABLE RESTART TEMPERATURE value selected in the
Functional Parameters away from setpoint. In the Frozen Range, restart is allowed when the compartment tem-
perature is calculated to be greater than 0.5F above setpoint. The MINIMUM OFF TIME parameter value may be
set from 10 to 90 minutes in 1 minute intervals. The factory default setting is 30 minutes. The RESTART TEM-
PERATURE value may be set from 0.5 to 18°F (0.28 to 10°C) in 0.5° (F or C) increments. The factory default is
5.4°F (-14.7°C).

If this is the only reason operation is required, the unit will operate as if it is in Continuous Operation until the
requirement has been met.

4. Compartment temperature has exceeded the Override Functional Parameter value

Override Functional Parameter value During MINIMUM OFF TIME the control system continually monitors the
refrigerated compartment temperature and the override functional parameter value. During the Minimum Off Time,
if the refrigerated compartment temperature drifts this far above or below setpoint in the Perishable Range, or
above setpoint in the Frozen Range, the unit will override the Minimum Off Time, and restart. The value may be set
from 3.6 to 18°F (2 to 10°C) in 0.5° increments. The factory default setting is 12°F (6.7°C).

Whenever the unit restarts, temperature control will be in the Pulldown or Pull-Up Mode.

4.5

CONTINUOUS OPERATION

In Continuous Operation, the unit will not shutdown except in response to a shutdown alarm. Temperature control
in the compartment will operate under Pulldown, Pull-Up, Cooling, Heating and Null.

Continuous Operation is normally used for fresh produce and other sensitive product loads. The Start-Stop/Contin-
uous key is pressed to switch between Continuous Operation and Start-Stop Operation. The mode of operation will
be indicated in the status bar.

NOTE

The control system may be locked so that the unit will always operate in Start-Stop or in Continuous
whenever the setpoint is within a specific range. Refer to Range Lock (

Section 4.8.2

) for additional

information.

4.6

TEMPERATURE CONTROL

4.6.1

Perishable And Frozen Setpoint Ranges

There are two ranges defined for setpoint.

a. Perishable Range = setpoints above +10.4°F (-12°C).

b. Frozen Range = setpoints at or below +10.4°F (-12°C).

4.6.2

Temperature Determination

The APX Control System monitors the temperature readings from the supply and return temperature sensors to
determine the mode of operation required to maintain compartment temperature in accordance with the setpoint.

The sensor used for temperature control is dependent on the selection made in the TEMP CONTROL Functional
Parameter.

• If the selection is RETURN AIR the return air sensor (RAT) will be used for any setpoint.

• If the selection is SUPPLY AIR the control system will switch to the supply air sensor (SAT) when operating

with a perishable setpoint (refer to

Section 4.6.1

for more information on frozen and perishable setpoints)

and the return air sensor will continue to be used for frozen setpoints.

The modes of operation include Pulldown, Pull-Up, Cooling, Heating and Null.