Carrier 69NT40-561-300, Руководство по эксплуатации и обслуживанию

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4–5 T-365
To access the function codes, perform the following:
1. Press the CODE SELECT key, then press an arrow key until the left window displays the desired code number.
2. The right window will display the selected function code value for five seconds before returning to normal
display mode.
3. If additional time is required, pressing the ENTER key will extend the display time to 30 seconds.
4.3 CONTROLLER SEQUENCE AND MODES OF OPERATION
General operation sequences for cooling, heating and defrost are provided in the following sub-paragraphs. Sche-
matic representation of controller operation is provided in
Figure 4.5 and Figure 4.8 .
Operational software responds to various inputs. These inputs come from the temperature sensors and pressure
transducers, the temperature set point, the settings of the configuration variables and the function code assignments.
The action taken by the operational software changes as the input values change. Overall interaction of the inputs is
described as a “mode” of operation. The modes of operation include perishable (chill) mode and frozen mode.
Descriptions of the controller interaction and modes of operation are provided in the following sub paragraphs.
4.3.1 Start Up - Compressor Phase Sequence
At start up, the controller logic checks for proper phase sequencing and compressor rotation. If incorrect sequenc-
ing is causing the compressor and three-phase evaporator and condenser fan motors to rotate in the wrong direc-
tion, the controller will energize or de-energize relay TCP as required (see
Figure 8.2 ). Relay TCP will switch its
contacts, energizing or de-energizing relays PA and PB. Relay PA is wired to energize the circuits on L1, L2 and
L3. Relay PB is wired to energize the circuits on L3, L2, and L1, thus providing reverse rotation.
4.3.2 Start Up - Compressor Bump Start
At start up, the controller logic will initiate a compressor bump start procedure to clear liquid refrigerant from the
compressor. If suction and discharge pressures have equalized, the compressor will perform three compressor
bump starts. A compressor bump start may also occur after a defrost cycle has been completed.
During Bump Start, the EEV will close. Relays TS, TG, TN, TE, and TV will be de-energized (opened). The result of
this action will close the ESV and shut all fans off. The compressor will start for 1 second, then pause for five sec-
onds. This sequence will be repeated two more times. After the final bump start the unit will pre-position the EEV to
the correct starting position, pause and start up.
4.3.3 Perishable Mode Temperature Control
In Perishable Mode, the controller maintains the supply air temperature at set point, the SUPPLY indicator light is
illuminated and the default reading on the display window is the supply temperature sensor reading.
When the supply air temperature enters the in-range temperature tolerance (Cd30), the green IN-RANGE light will
energize.
When CnF26 (Heat Lockout Temperature) is set to -10°C, perishable mode is active with set points above -10°C
(+14°F). When CnF26 is set to -5°C, perishable mode is active with set points above -5°C (+23°F).
4.3.4 Perishable Steady State
Perishable Steady State is used to maintain he control temperature near a set point that is above the heat lockout
temperature.
On a properly loaded box, the unit will operate in steady state mode. This results in unloaded operation by cycling
the DLV and DUV to limit capacity and maintain steady temperature control.
The unit is capable of maintaining supply to /-0.2°C (+/-0.36°F) of set point. Supply air temperature is con-
trolled by positioning of the EEV, cycling of DLV and DUV, cycling of the compressor, and cycling of the heaters.
4.3.5 Perishable Idle, Air Circulation
Perishable Idle Mode is used when it is unnecessary to run the compressor to maintain control temperature. If tem-
perature drops to 0.2°C (0.36°F) above set point, the controller determines that cooling is not required or the con-
troller logic determines suction pressure is at the low pressure limit, the unit will transition to Perishable Idle Mode.
During Perishable Idle Mode, the compressor is turned off, but the evaporator fans continue to run to circulate air
throughout the container. If temperature rises +0.2°C (+0.36°F) above set point, the unit will transition back to per-
ishable steady state.