Document Part # 026-4600 Rev 3 23-APR-2008
Page 5 of 8
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Control Link RSC Installation Instructions
technical bulletin
code will continue until the temperature returns to normal (1°F below high temp alarm setpoint or 1°F above low temp set-
point) or until the Alarm Silence button is pressed (alarm is suspended for 5 minutes, then will reoccur if problem is still
active).
Defrost Operation
Defrost cycles are initiated at the times programmed in the CL-RSC. During defrost, the compressor relay is de-energized,
and the defrost relay is energized. The defrost relay will be de-energized when the defrost termination temperature is
reached or until the programmed defrost duration has elapsed (whichever occurs first). While the defrost relay is energized,
the display will show
dEF
instead of the case temperature.
If a defrost drip duration has been programmed, immediately after defrost termination the compressor relay will remain
OFF for an amount of time to allow moisture to drain off the coil. During this time, the display will read
drIP
. When the
drip time is over, refrigeration will resume. Fans may be either off or on during defrost, based on user programming.
Manual Defrost
A manual defrost may be initiated at any time by holding the SET button for 10 seconds until the
dEF
message is shown on
the display. Defrost will begin immediately and terminate normally. If one of the auxiliary inputs is configured as a manual
defrost switch, a contact closure on the switch will also initiate a manual defrost.
Compressor Fail-Safe Mode
If the case temperature sensor fails, the CL-RSC will operate in a fail-safe mode that cycles the compressor ON and OFF at
a user-defined regular interval. The ON/OFF rate is determined by setting parameters
CSFP
and
CSFO
in the CL-RSC.
CSFP
sets the interval period, and
CSFO
sets the amount of time during that period the compressor will be ON.
For example, if during fail-safe you want the compressor to alternate being ON for three minutes and OFF for seven min-
utes, set
CSFO
to 3 and
CSFP
to 10. This will cause the compressor to be ON for three minutes of the 10 minute interval, and
OFF for the remaining seven minutes.
Output Board Comm Loss/Power Loss Fail-Safes
The 618-1120 Output Board has Form C contacts. The fan and contactor/solenoid outputs are wired to the normally closed
(N.C.) contacts on the board, meaning refrigeration and fan outputs will fail to the CLOSED state when power is lost or
communication with the RSC is lost. The defrost and auxiliary outputs are wired to the normally open (N.O.) contacts,
meaning these fan outputs will fail to the OPEN state.
Auxiliary Relay Control
The auxiliary relay on the Relay Expansion board, or relay #2 on the Control Link main module, may be used to control
various functions:
•
Defrost
(only an option for relay #2 if no Expansion Board is used).
•
Lighting Control:
Up to six ON/OFF times per day may be programmed for case lights. If not connected to an E2, the Control
Link main module will require a real-time clock module to perform lighting control.
•
Case Fans:
Fans can be programmed to be always ON, or ON only when the compressor is ON. Other features include program-
mable fan state during defrost, and suspension of fan activation after defrost based on time and/or case temperature.
•
Alarm:
The relay will close when an alarm is active on the Control Link main module.
