Danfoss EKE 1A User Manual page 54

Superheat controller, Type EKE 1A, 1B, 1C, 1D
Table 39: Thermostat Failsafe mode
Thermostat Failsafe mode
Thermostat sensor error.
Thermostat operation needs the signal selected in [R015 Sensor select] to oper-
ate the thermostat function, if this signal fails operation based on actual tempera-
ture is not possible
Table 40: Thermostat Failsafe mode parameters
Parameter Function
N144 Thermostat sensor error action
N145 [only if N144= 1] Fixed OD during emergency cooling
N138 [only if N144= 2] Average OD
Superheat close
SH close ensures that superheat is on or above 'SH close set point to avoid liquid getting back to the compressor. If
the media inlet temperature drops or if compressor goes down in capacity, the superheat may drop below the SH
close setpoint, then the flow in the expansion valve is reduced to bring superheat up to SH close setpoint as shown
in the figure below.
Figure 78: SH close operation
Superheat
Auto SH control
SH Ref
SH close
setpoint
Table 41: Superheat close Parameters
Parameter Function
N117 SH close function
N119 SH close setpoint
Lowest Operating Pressure (LOP)
Lowest Operating Pressure (LOP) will make sure that the evaporating pressure (Pe) is kept above LOP set point, this
will prevent the compressor from stopping due to low suction pressure. If the pressure comes below this limit the
controller will quickly open the valve.
© Danfoss | Climate Solutions | 2022.06
SH close is active
reducing OD fast
Auto SH control
to get SH back to
reference
Compressor capacity
Description
User can via parameter [N144] Thermostat sensor error action] configure the rel-
evant option.
Stop valve forced closed, SH control and Temperature control (default)
Fixed OD valve at fixed position (Fail safe OD). This Keeps the refrigeration
running
Use Average OD Cutin /cutout use average on and off time to continue cool-
ing
MTR use reduced OD based average OD (70% of average
OD).
Description
0 = Stop | 1 = Fixed OD | 2 = Average OD
Define fixed OD % during Emergency cooling
Calculated When superheat control/ Temperature control is ac-
tive and stored in EEPROM. Its value is updated every 3 hours.
Reset to factory will not delete the calculated average values.
Used in average OD
Superheat
OD
Time
Description
0 = Off | 1 = On, default Valve = On
Default value =2 K
BC398828796060en-000101 | 54