62-11640 4–10
Supply Air Limit Control is set using the PERISHABLE
SENSITIVE PRODUCT Functional Parameter (which
can be set to OFF or ON), and the SUPPLY AIR LIMIT
FOR START-STOP Operation Configuration or SUP-
PLY AIR LIMIT FOR CONTINUOUS Operation Config-
uration (each of which can be set from 0 to -21.6°F [0
to -12°C]).
NOTE
These values are all negative (except for 0),
therefore, when the value is added to the
setpoint, the result will be a temperature that
is less than the setpoint.
When the PERISHABLE SENSITIVE PRODUCT Func-
tional Parameter is set to OFF, the supply air tempera-
ture will be the coldest temperature of 32°F (0°C) OR
the calculated value of Setpoint minus the configured
Supply Air Limit value.
When the PERISHABLE SENSITIVE PRODUCT Func-
tional Parameter is set to ON, the supply air tempera-
ture will be the calculated value of setpoint minus the
configured Supply Air Limit value.
Supply Air Limit controls the temperature of supply air
as it leaves the evaporator so it does not go colder than
the configured Supply Air Limit value below setpoint.
NOTE
The 9°F value used in the following exam-
ples is not necessarily a recommend setting,
but is only used to show how the Supply Air
Temperature Limit is calculated.
4.10.2 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, Range Lock 1
and Range Lock 2. Each Range can be independently
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 are contained in
both ranges due to range overlap, Range 1 will always
have priority over Range 2.
Typically, both Range Lock 1 and Range Lock 2 are
used to control different setpoint ranges when IntelliSet
is not active. For units with IntelliSet active, because
each IntelliSet is generally programmed for a specific
product, only Range Lock 1 is used to hold the unit in
either the Start/Stop or Continuous Operation, and
Range Lock 2 is left off.
For example (see Figure 4.2), if Continuous Operation
is ALWAYS required whenever the setpoint is between
28°F and 55°F (-2.2°C and +12.8°C), Range 1 will be
set for Continuous, with a Minimum Temperature of
28°F (-2.2°C) and a Maximum Temperature of 55°F (-
12.8°C).
Should Continuous Operation ALWAYS also be
required with setpoints between -22 and 0°F (-30 and -
17.8°C), then Range 2 will be set for Continuous, with a
Minimum Temperature of -22°F (-30°C) and a Maxi-
mum Temperature of 0°F (-17.8°C). Any setpoint out-
side of Range 1 or 2 will allow changes between Start-
Stop and Continuous.
EXAMPLE 1: Perishable Sensitive Product Functional Parameter = OFF
Supply Air coldest temperature limit is the colder temperature of:
+32
F OR
Setpoint minus configuration value for Supply Air Limit
Sample Calculations:
05tniopteS F45F40F33F
Supply Air Limit Configuration Value -9
F -9 F -9 F -9 F
Setpoint minus Supply Air Limit 41 F36F31F24F
Coldest Supply Air Temperature allowed 32 F32F31F24F
EXAMPLE 2: Perish Sensitive Product Functional Parameter = ON
Supply Air will be limited to setpoint minus configuration value for Supply Air Limit.
Sample Calculations:
Setpoint 50 F40F33F
Supply Air Limit Configuration Value -9 F -9 F -9 F
Setpoint minus Supply Air Limit 41 F31F24F
Coldest Supply Air Temperature allowed 41
F31F24F
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