Product Overview
Table Of Contents
© Danfoss | DCS | 2019.04
Data sheet | Superheat controller type EKE 1A, EKE 1B, EKE 1C
DKRCC.PD.RS0.A4.02 | 52
19.2 Superheat close
EKE 1A 1B 1C
Applicable
SH close secures that superheat is kept on or above SH close set point. This is done in order 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. SH close is a fast control
function which reduces the ow in the expansion valve to bring superheat up to SH close setpoint.
Parameter Function Description
N117 SH close function 0 = O | 1 = On, default Valve = On
N119 SH close setpoint Default value =2 K
19.3 Lowest Operating
Pressure (LOP)
EKE 1A 1B 1C
Applicable
This feature is typically used in application such as Heat pump to operate at lower ambient
conditions . Lowest Operating Pressure (LOP) will make sure that the evaporating pressure (Pe) is
kept above LOP set point. During startup at low outdoor temperature and when compressor change
to higher capacity, it may be needed to keep the suction pressure above LOP set point to avoid stop
on low pressure switch. In such conditions, the only way to keep the unit running is by letting LOP
override SH control.
This feature 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 .
Warning:
As default, controller will not
allowed to open the valve when
the superheat is low.
If such feature is needed for a
short time, parameter ”N142
LOP priority mode” can be set to
ON This will allow LOP to have
higher priority than bringing the
superheat out of low superheat
for the time dened in ”N131
LOP max. time”. Care should be
take that compressor can
handle this condtion.
Parameter Function Description
N140 LOP function 0 = O | 1 = On, default Valve = O
N141 LOP setpoint °C
Lowest Operating Pressure setpoint.
Setpoint unit is saturated temperaure in evaporator-40 °C, default
N142 LOP priority mode
In case of conict between low pressure and SH close, LOP function can
be set to override SH close actions. (Could be needed for startup in low
ambient temperatures)
On: LOP can override low superheat
0 = O | 1 = On, default= O
N131 LOP max. time Maximum time for LOP to override SH close 120 sec , default
Compressor capacity
OD
Superheat
SH close is active
reducing OD fast
to get SH back to
reference
Time
Superheat
SH Ref
SH close
setpoint
Auto SH control
Auto SH control
Danfoss
80G357.10
Compressor
start
Outdoor
temp
Lop setpoint
OD
Superheat
Te evaporator temperature
Valve is opening to
avoid Te going lower
Danfoss
80G358.10