Carrier 69NT40-561-300, Operation And Service Manual

Page: 103 / 174

5–5 T-365
5.4.3 eAutoFresh Modes of Operation
NOTICE
When setting any mode of operation, complete the entire process to ensure all parameters are set.
a. OFF
A setting of OFF will disable all automatic venting operations. The eAutoFresh vent will be driven fully
closed and the eAutoFresh opening set to 0 CMH in Cd44. This is the default mode whenever a frozen
mode of operation has been selected. When the frozen set point is selected, the current eAutoFresh set-
ting is saved. The vent position will be restored when a perishable set point is selected.
b. USER
The USER mode provides ventilation for commodities that require fresh air circulation. The flow rate
can be accessed through the submenu if a perishable set point has been selected. To set the flow
rate, press the ENTER key to activate the selection mode. When FLO appears in the left hand win-
dow, use the UP or DOWN arrow key to scroll to the desired opening. The range is from 0 to 220CM
(0 to 129CF) in increments of 5. Press the ENTER key to set the value and begin operation.
c. TEST
TEST mode allows the operator to test the movement of the mechanical slide air vent and calibrate the
CO
2
sensor.
tESt − When “tESt” appears in the left window, press the ENTER key to begin the test. The eAutoFresh
slide will open fully and then return to the closed position. The test may be observed by the operator to
ensure proper operation of the vent. After completion of the TEST, the unit will return to the previous
mode of operation.
NOTICE
It is recommended that the calibration procedure only be performed during Pre − trip or when
the container has been fully vented.
CAL will attempt to calibrate the CO
2
sensor. When “CAL“ is selected the display will flash “CAL“. The
operator is to hold the “ENTER“ key for 5 seconds. The display will stop flashing and read “CAL“ for 5
seconds. The microprocessor will read the CO
2
value, and then compare that value to a known zero
value. If the sensor is within the calibration parameter range, the microprocessor will determine the
appropriate offset for the sensor. If the sensor is outside of this range, for example if the container is
loaded or has a high level of CO
2
, the controller will flash “NOCAL“ for 5 seconds then revert to the pre-
vious mode of operation.
d. DELAY
In DELAY mode, the operation of the eAutoFresh system will be delayed for a set amount of time. This
allows time for the cargo to reach set point. In DELAY mode, the eAutoFresh vent will open to the stored
(FLO) value when the return air temperature sensor (RTS) is at or below set point plus the return offset
value (rtn) or the delay time (tIM), whichever comes first. The eAutoFresh vent will be fully closed when
return air temperature is greater than the set point plus the offset temperature (rtn).
To set the unit in Delay mode, scroll until “DELAY“ appears in the left window, press ENTER to activate
the submenu. The first selection is the amount of time (tIM) for the delay. Select the amount of time for
the delay by using the UP and DOWN arrow keys. The range is from 1 to 72 hours in 1 hour increments.
Press the ENTER key to set the value and move to the FLO rate. Use the UP or DOWN arrow key to
scroll to the desired FLO rate.
The range is from 0 to 220CM (0 to 129CF) in increments of 5 and 3 respectively. Press the ENTER key
to set the value and move to the return temperature offset. Use the UP or DOWN arrow key to scroll to
the desired rtn rate. The range of offset is from 0.6C to 2.8C (1.0F to 2.8F) in 0.1 increments. Press
ENTER to set the value and begin operation.