4–9 62-12259
When Null mode is required and the system is operating in:
• Engine/Start-Stop Operation: The unit (engine, compressor, condenser fans and evaporator fans) will shut
down if the remaining Stop Parameters have been satisfied.
• Engine/Continuous Operation: The compressor will shut down while the engine and evaporator fans con-
tinue to operate. The condenser fan will operate if engine cooling is required.
• Standby Continuous Operation: The compressor and condenser fans will shut down while the evaporator
fan continues to operate.
NOTE
In Continuous Run, when difference between ambient and setpoint is < 10°C, the COMPRESSOR
RESTART OFFSET configuration value will be used for the switch point to turn cool on (instead of
0.2°C). If the ambient and setpoint are more than 10°C then the switch point remains 0.2°C.
4.6.4 Cool Mode
When Cool mode is required the system will operate in Pulldown or CSMV Control. Pulldown operation will include
periods of time in Economized mode and Standard mode. CSMV control will occur in Standard mode. for descrip-
tions of operation when cooling, with flow diagrams, refer to Section 2.13.
Control Temperature with Fuel Saver OFF
COOL MODE
Switch ON when CT-SP is
greater than or equal to
0.36°F (0.2°C)
Switch OFF when CT-
SP is less than -0.36°F (-
0.2°C)
NULL MODE
Between Cool and Heat or Heat and Cool
HEAT MODE
Switch On when CT- SP is
equal to or less than -0.54°F
(-0.3°C)
Switch Off when CT-
SP is greater than
0.36°F (0.2°C)
Control Temperature with Fuel Saver ON
COOL MODE
Switch On when CT- SP is
greater than or equal to the
S/S OVERRIDE Functional
parameter.
Switch Off when CT-SP
is less than -0.32°F (-
0.0°C)
NULL MODE
Between Cool and Heat or Heat and Cool
HEAT MODE
Switch On when CT-SP is
equal to or less than -1.44°F
(-0.8°C)
Switch Off when CT-SP
is greater than 1.26°F
(0.7°C)
To Next Page
Loading...
