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ELECTRONIC CONTROL OPERATION
(Refrigerated Models Only)
Operation
The control uses two sensors, one located in the air stream and one located on the evaporator coil.
The sensor located in the air stream is referred to as the temperature control sensor. The sensor
located on the evaporator coil is referred to as the defrost probe.
The temperature control sensor is located on the plastic tub behind the evaporator coil on the
centerline of the display case in the cold air stream. The sensor location is critical for proper
operation on the unit. Do not move or relocate this sensor.
The coil sensor is strapped to the evaporator coil. This sensor location is critical for proper
operation of the unit. Do not move or relocate this sensor.
The temperature control is set to cut in at 38°F (3.3°C). The Temp control cuts out at 24°F (-4.4°C)
at the coldest setting (“9”) and 32°F (0.0°C) at the warmest setting (“1”).
Defrost Cycle
The control is programmed to initiate defrost via two different methods. There are 3 programmed
defrost cycles in the case which will initiate a defrost cycle every 8 hours. The unit does not have a
time clock so the defrost cycles cannot be set for any specific time of day.
The unit also has an ‘On demand’ defrost feature that will initiate a defrost when the temperature
differential between the evaporator temperature and the air temperature is more than 18°F (-7.8°C)
for 5 minutes into the refrigeration cycle (e.g. if the air stream probe measures 32°F/0°C or greater
and the defrost probe measures 20°F/-6.7°C or lower for five minutes). Once initiated the defrost
cycle will terminate when evaporator coil sensor reaches 43°F (6.1°C).
If a manual defrost is required, one can be initiated by pressing and holding the down arrow for
approx. five seconds. This is typically unnecessary and should only be performed if special
circumstances require it.
Control Parameters
Table 1 - Control Parameters
Parameter Description
Control Setpoint
1
2
3
4
5
6
7
8
9
Compressor Cut in [°F]
38.0
Compressor Cut out [°F] 32.0 31.0 30.0 29.0 28.0 27.0 26.0 25.0 24.0
Compressor Min On Time
2 min
Compressor Min Off Time
2 min
Compressor Max Run Time
60 min
Defrost Termination Temp [°F]
43.0
Time to first defrost
8 hr
Time to subsequent defrost
8 hr
Defrost duration
30 min
Defrost on demand differential [°F]
18.0
Delay for defrost on demand
5 min
Time delay to the next defrost on demand
30 min
