Carrier NDK33BN0KB, Operation & Service Manual

Page: 89 / 270

62-61753-21 4-7

the START-STOP SUPPLY AIR LIMIT Differential
Configuration value
OR

the CONTINUOUS RUN SUPPLY AIR LIMIT Dif-
ferential Configuration value
AND

the Perishable Sensitive Product Functional Pa-
rameter Setting.
The supply air limit temperature is determined by the
formula: Set Point (SP) + Configured Differential Value
(CDV) = Target Supply Air Limit (TSAL).
The CDV may be set from -12 to 0

C (-21.6 to 0

F) in
0.5°C or F intervals. The factory default setting for
Start-Stop is -6.0

C (-10.8

F) while the factory default
setting for Continuous Operation is -5.0

C (-9

F).
Example 1:
Metric - if SP is 2°C and the CDV is -6

C the calcula-
tion would be:
2°C + (-6

C) = -4°C
English - if SP is 35.6°F and the CDV is -10.5

F the
calculation would be:
35.5°F + (-10.5

F) = 25.0°F
Example 2:
Metric - If the set point is 10°C and the CDV is -6

C
the calculation would be:
10°C + (-6

C) = +4°C
English -If the set point is 50°C and the CDV is -
10.5

F the calculation would be:
50°F + (-10.5

F) = 39.5°F
With the Perishable Sensitive Product Functional Pa-
rameter set at the default (NO) setting, supply air limit
control is not allowed until the supply air temperature:
falls to 0°C (32.0°F) and then it will control to 0°C
(32.0°F)
OR to the calculated limit (TSAL) if the calcu-
lated limit is below 0°C (32.0°F).
In example 1 above the CSMV would throttle to control
the supply air temperature at -4°C (25.0°F) while in
example 2, it will control to 0°C (32.0°F)
If the sensitivity of the product is such that tempera-
tures must be maintained above freezing, the Perisha-
ble Sensitive Product Functional Parameter is
changed to YES. With this setting, the limit control will
not allow supply air temperature to fall below 0°C
(32.0°F).
In example 1 above the CSMV would throttle to control
the supply air temperature at 0°C (32.0°F) while in
example 2, control would begin when supply air tem-
perature falls to 4°C (39.5°F).
NOTE
The pulldown and engine run time is heavily
dependent on the Supply Air Limit Configura-
tion Setting and resultant calculated Target
Supply Air Limit (TSAL). Expect longer pull
down and engine run times when the Supply
Air Limit Control Setting is configured to small-
er numerical values. Longer pull down times
can also be expected if the Perishable Sensi-
tive Product Functional Parameter is set to
YES.
4.6.2 Temperature Range Lock 1 & 2
Range Lock is a group of Configurations which may be
set to lock the unit into Start-Stop or Continuous Oper-
ation for various setpoint ranges. Two ranges are
available for selection. Each Range can be inde-
pendently set to lock it’s setpoint temperatures into
either Start-Stop or Continuous Operation.
Each Range has it’s own selectable minimum and
maximum temperature, which define the span of the
range. If some setpoint temperatures may contained in
both ranges due to range overlap, Range 1 will always
have priority over Range 2.
For example (see Figure 4-2), if Continuous Operation
is ALWAYS required whenever the setpoint is between
-2.2°C and +12.8°C (28°F and 55°F), Range 1 will be
set for Continuous Operation, with a Minimum Tem-
perature of -2.2°C (28°F) and a Maximum Tempera-
ture of -12.8°C (55°F). Should Continuous Operation
ALWAYS also be required with setpoints between -
30°C (-22°F) and -17.8°C (0°F), then Range 2 will be
set for Continuous Operation, with a Minimum Tem-
perature of -30°C (-22°F) and a Maximum Tempera-
ture of -17.8°C (0°F). Any setpoint outside of Range
1 or 2 will allow changes between Start-Stop and Con-
tinuous Operation.