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run in ‘SAFETY MODE’ as described previously. The ‘communication alarm’ clears when it receives any
command from that controller.
The controllers switch between ‘COOL’ mode and ‘OFF’ mode based on the warmest temperature
reading from all controllers that have a room temperature sensor.
If any controller decides to go in defrost, all controllers will then go into defrost.
If any controller decides to go in drain mode, all controllers will then go into drain mode.
If any controller decides to go in fan delay mode, all controllers will then go into fan delay mode
If there is a communication alarm at any controller, then the controller will go into defrost as a scheduled
defrost that will terminate on time only.
ALTERNATING MODE
The controller can be configured as an alternating system for dual single-evaporator refrigeration units to
provide redundancy of a refrigerated cold room. Once the network is set up, a CAT/5E cable can be connected
between the 2 controllers, connected to the RJ-45 connector. When the alternating mode is selected, the dual
refrigeration units will start pulling down box temperature to the cut-out set point then both go into OFF
MODE(OFF). When the box temperature rises up to cut-in temperature, the one of the units will come on while
the other stays off. The other evaporator will perform the refrigeration in next cooling cycle.
IMPORTANT NOTE:
In the controller, the parameter of “DFMD” has to be set for proper method of defrost. “DFMD = ELEC”
is for regular electric defrost; “DFMD = HGDF” is for regular reverse cycle defrost;
Definition of On-Board Symbols
STATUS, DEFAULT AND READING DISPLAY
When the on-board green light is on, the compressor relay is energized. When the green light is blinking, the
room temperature sensor is satisfied, but waiting for the minimum off timer or minimum run timer to time out.
When the red light is on, there is a critical alarm. When the amber light is on, there is a non-critical alarm.
The status and the digital data are displayed on the onboard four-digit LED display. Below is a list of the
parameters of the operational status.
Onboard
Four-Digit
Display Description
STUP Indicates the status of Start Up Mode
CKFN Check fan working status
CKP1 Check pressure transducer
OKP1 Indicates the pressure transducer is working as it should
CKT1 Check sensor TS1, the suction/fan cut-in temperature sensor
OKT1 Indicates the TS1 is working as it should
CKT2 Check sensor TS2, the room temperature sensor
OKT2 Indicates the TS2 is working
CKT3 Check sensor TS3, the coil temperature sensor
OKT3 Indicates the TS3 is working
CKFH Indicates all sensors are OK
FNDL Indicates FAN DELAY MODE
FDTP Actual TS1 value in FAN DELAY
COOL Indicates COOL MODE
OFF Indicates OFF MODE
PMDN Indicates PUMPDOWN MODE before an electric defrost
DEFR Indicates DEFROST MODE
DRAN Indicates COIL DRAIN MODE
DFTP Inlet sensor TS3 value in DEFROST MODE
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