Danfoss EKE 1A User Manual page 78

Superheat controller, Type EKE 1A, 1B, 1C, 1D
ID Symptom
11 Superheat outside the de-
fined range or does not
reached the setpoint
12 Takes too long to settle SH
at reference point
13 Startup problem
14 Startup problem after de-
frost
15 Unable to maintain media
temperature
© Danfoss | Climate Solutions | 2022.06
Possible cause/Reaction
Wrong valve selected or its valve parameter.
Loss of refrigerant in the system.
Expansion valve too small.
Step loss in the valve.
Too low gain Kp and KpTe or long integration time Tn.
At start up. the pull-down time for SH or temp is longer.
Wrong selection of the valve.
Wrong selection of the reference point.
low pressure cut out at start up
Unsynchronized signals.
High Superheat after startup.
low suction cut out
Lack of sub-cooling ahead of expansion valve
Check section High superheat and Low suction Pressure
Wrong selection of temperature sensor and or installation.
Check Working condition of the unit
Solution
• Check the right valve type and its setting.
• Charge the system with appropriate refrigerant capaci-
ty.
• Check for leakage in the system.
• Replace with larger valve if necessary.
• Check the selected valve in the controller valve list.
• Drive the stepper valve with the recommended Speed.
• Too high or too low speed could result in loss step in
the valve.
• For the user defined valves, check the other valve set-
tings such as current, duty cycle, holding current and
another relevant parameter.
• Use overdrive features to mitigate the loss steps. Use
the correct overdriving values with respect to the used
value.
• Wrong defined valve type or its setting.
• Longer cables mounted than specified for the control-
ler.
• Separate Valve cable from other high-power cables and
do not bundle the cables.
• Obstruction in the valve or high friction in the valve.
• MOPD exceeded than specified in the valve specifica-
tion.
• Increase Kp by factor of 1.5%
• Decrease Tn 25% of the set value
• Perform 1 and 2 in a loop if needed.
• Use start with P. control and increase start OD.
• If the superheat in general is 4K higher than reference 1
minute alter start up. the startup OD can be adjusted to
be 20 % higher.
• Check the valve type and in setting.
• Correctly define the min, max SH setting and/or refer-
ence type i.e MSS/Load defined ap / Fixed/delta Temp.
• Also check section, High superheat and 'Too high and
too low superheat'
• Check the LEO Alarm connection.
• Missing synchronization with controller and the com-
pressor Le. D4 not connected to EKE.
• Wrong Of missing valve connection. Check the M12 ca-
ble connection to the valve and to the controller.
• Check other component in the suctions liquid 'Meta
any keel of blockage.
• Use the LOP feature during start up.
• Make sure that main switch signal and the compressor
start are synchrony, it ok to have until 2 sec delay.
• Check section Too high or too low superheat.
• Use EKE defrost sequence feature.
• Use LOP feature
• Use P- control at start method and prolong the start
tine
• Check the right signal from the controller.
• Limit max opening degree of the valve setting in con-
troller.
• Check refrigeration system capacity and compare with
expansion valve capacity. Use proper valve size suitable
for the system.
• Check for the right sensor configuration
• Check Superheat.
BC398828796060en-000101 | 78