Functions
Temperature sensors
One thermostat sensor – Sair – can be connected to the controller, and the relevant application defines the
placement. It can be placed in the air flow before the evaporator or in the air flow after the evaporator. The latter is
mainly used where there is a risk of too low temperature at the products.
Figure 3: Refrigerated cabinet shown with sensor positions
Danf
oss
80G8430
S
air
S
air
S
c
S5
Defrost sensor
The best signal concerning the evaporator’s temperature is obtained from a S5 defrost sensor mounted directly on
the evaporator. Here the signal may be used by the defrost function, so that the shortest and most energy-saving
defrost can take place. If a defrost sensor is not required, defrost can be stopped based on time, or Sair can be
selected.
Condenser temperature sensor
A condenser temperature sensor – Sc – can be used for monitoring the temperature on the condenser. Depending
on settings, alarms can be generated, and a safety stop of the compressor, can be initiated based on this
temperature.
Voltage protection
The voltage protection ensures that the compressor motor is operating within safe voltage ranges. If the power
supply voltage gets outside the specified high/low voltage cut-out ranges, the compressor is cut-out or restricted
from starting. Normal compressor operation is resumed when the power supply voltage is back in the area between
the high voltage cut-out limit and the low voltage cut-in limit.
Figure 4: Voltage protection
High voltage cut-out
limit (alarm and
compressor stop)
Low voltage cut-in
limit (compressor start)
Low voltage cut-out
limit (alarm and
compressor stop)
Danf
oss
80G8457
Condenser temperature monitoring
If the condenser is blocking up with dirt and thereby reaches a too high condensing temperature, the controller will
give the user early warning through condenser alarm and if temperature rises further, it will switch the compressor
OFF. If the temperature measured by the condenser sensor (Sc) is reaching the set “pre-alarm limit” an alarm is
raised, but no further action is taken.
© Danfoss | Climate Solutions | 2023.05
BC432222569027en-000201 | 7
Case controller, type EKC 223 and EKC 224