Johnson Controls System 450 Series Technical Bulletin

Table 10: Refrigeration settings
Symbol Settings Default
setting
Description
SP -40°F to 122°F
-40°C to 50.0°C
35°F
1.7°C
Space temperature set point
• The refrigeration output turns off when the refrigerated space
temperature is less than or equal to the set point.
dIFF 1°F to 15°F
1°C to 8.0°C
3°F
1.5°C
Space temperature differential
• Differential is the temperature value, in degrees that is added
to the SP value to provide a cut-on setpoint for the refrigeration
output.
• When the refrigerated space temperature warms to a value equal
to the setpoint plus the differential, the refrigeration output turns
on.
SNF On: Refrigeration ON
OFF: Refrigeration
OFF
CYC: Cycle
Refrigeration
On Sensor 1 failure mode
• The sensor failure defines the action that the control takes if the
Sn-1 space temperature sensor fails.
• CYC turns the refrigeration output ON and OFF at a rate equal to
the average rate of the last four ON and OFF cycles prior to the
sensor failure.
Note: OFF periods during defrost are not included in the
average OFF times. In this mode, the ASD parameter is
observed during the OFF periods.
ASD 0 to 12 min 1 min Anti-short cycle delay:
• The anti-short cycle delay is the equivalent of a minimum OFF time.
• ASD ensures that every time the refrigeration relay, OUTR1 output
turns OFF, the relay output remains OFF for a period of time equal
to what is set on the ASD setting.
• ASD prevents rapid ON or OFF cycling of the compressor. This is
short cycling.
Table 11: Pump down settings
Symbol Settings Default setting Description
• P100 sensor: 0.0 to 100.0
• P110 sensor: -10.0 to 100.0
• P200 sensor: 0 to 200
25 psiON
• P8 Sensor: -1.0 to 8.0
• P15 Sensor: -1.0 to 15.0
1.7 bar
Cut-in setpoint:
The cut-in setpoint is the pressure at which the
compressor turns ON. When the Sn-3 pressure reading
is greater than or equal to the ON setpoint, the
compressor turns ON.
• P100 sensor: 0.0 to 100.0
• P110 sensor: -10.0 to 100.0
• P200 sensor: 0 to 200
15 psiOFF
• P8 Sensor: -1.0 to 8.0
• P15 Sensor: -1.0 to 15.0
1.0 bar
Cut-out setpoint:
The cut-out setpoint is the pressure at which the
compressor turns OFF. When the Sn-3 pressure
reading is less than or equal to the OFF setpoint, the
compressor turns OFF.
SNF • ON: Compressor ON
• OFF: Compressor OFF
ON Sensor 3 fail mode:
Action to take in the event of a pressure sensor failure.
25System 450 Series C450CCU Condensing Unit Control System Technical Bulletin

Johnson Controls System 450 Series Specifications

General

Brand	Johnson Controls
Model	System 450 Series
Category	Control Unit
Language	English