Johnson Controls System 450 Series Technical Bulletin

Table 12: Defrost settings
Symbol Settings Default setting Description
dUR 0 to 99 min 30 min Defrost duration
• The defrost duration defines maximum length, in minutes, for each
defrost duration. If the defrost termination temperature is not reached
on temperature-based defrost termination applications, the defrost cycle
terminates when the duration time elapses.
TERM 30°F to 90°F,
-1.0°C to
32.0°C
40°F, 4.5°C Termination temperature:
• When the Sn-2 defrost termination sensor is available, you can use the
termination temperature to define when a defrost cycle ends.
• If the termination temperature is reached before the defrost cycle
duration elapses, the defrost cycle ends.
• In all cases, the defrost cycle ends when the duration time period is met.
dRIP 0 to 10 min 5 min Drip time:
• The drip time parameter is available when the defrost type is active.
• Drip time is the number of minutes that the control delays after turning
off the defrost heater and before evaporator fans and compressor
restarts in normal refrigeration mode.
FDLY 0 to 15 min 5 min Evaporator fan delay time after defrost
• The evaporator fan delay parameter is available when the defrost type is
active. The evaporator fan delay is applied when a defrost finishes and
the control enters refrigeration mode.
• During this delay period, the refrigeration is ON and the evaporator fan
remains OFF.
dF-1 12:00 A.M. to
11:59 P.M.
12:00 A.M. Schedule: Defrost 1
• Time is expressed in 12Hr or 24Hr format based on CLK setup.
• Setting range is 12:00 A.M. to 11:59 P.M. Unused defrost times are
indicated with dashes.
dF-2 4:00 P.M. Schedule: Defrost 2
dF-3 --:-- or None Schedule: Defrost 3
dF-4 --:-- or None Schedule: Defrost 4
dF-5 --:-- or None Schedule: Defrost 5
dF-6 --:-- or None Schedule: Defrost 6
dF-7 --:-- or None Schedule: Defrost 7
dF-8
Time is
expressed in
either a 12h
or 24h
format,
based on CLK
setup.
Unused
slots show
the following
blinking sign:
--:--
--:-- or None Schedule: Defrost 8
System 450 Series C450CCU Condensing Unit Control System Technical Bulletin26

Johnson Controls System 450 Series Specifications

General

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