Danfoss EKE 1C User Manual

ID
Symptom
Possible cause/Reaction
Solution
4
Liquid hammer in compres-
sor (noisy or unusual com-
pressor sound) and /or frost
on the suction line
Superheat reference set too low.
• Increase the SH reference by changing the SH min.
max. parameter.
Superheat is too low.
• Make sure SH Close function is ON.
• Increase the values of SH close and SH min.
• Also check section "Too low superheat"
Inaccurate SH measurement or slow response in S2 sen-
sors.
• Ensure that S2 sensor is secured on suction line.
• Insulate temperature sensor properly.
• Check the product installation guide section tempera-
ture sensor.
Refrigerant or pressure transmitter is not set correctly.
• Check the related parameters.
5
Too Low superheat
Min. SH parameter is too low set.
• Raise the min. SH parameter.
Valve Cannot Close fully.
• Reduced the Valve OD or forced opening time at Start
up.
Valve OD too large at start up.
• Use P-control.
• Reduce Start OD.
Inaccurate superheat.
• Mounting position of Temperature sensor. Place sensor
close to evaporator.
High-pressure drop-in suction line.
• Mounting position of the pressure transmitter. Place
the transmitter close to evaporator.
• Check the product installation guide section tempera-
ture sensor.
Valve is stuck at open.
• Check valve installation.
Liquid returns to compressor.
• Check section Liquid hammering.
6
High superheat
Lack of sub-cooling.
• 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.
Controller is not setup/tuned properly.
• Check the controller superheat settings SH min, SH max
and sensors connected to it.
• Tune PID parameters in the controller.
Wrong valve selected from the controller list or undersized
valve installed.
• Check the right valve type and setting or use the ap-
propriate valve size for the needed condition.
Seasonally high load condition or overloaded the system.
• Check the heat exchanger for dirt's.
• Check superheat performance.
7
Too high or too low meas-
ured superheat
Wrong sensor type, refrigerant type, pressure transmitter
type and/or range.
• Check the related setting and range.
• In case of oset in sensor or pressure transmitter, per-
form the sensor correction.
• Always use accurate pressure transmitter
8
Measured Superheat is
higher than reference -
more than 5K for 5 - 10 min.
Load condition has changed, and the superheat controller
is too slow to adapt to the change.
• TN can be adjusted to 20% lower and Kp can be adjus-
ted to be 20% higher, monitor that the adjustment
doesn’t make the valve OD and Pe/Te oscillate.
Compressor capacity has changed, and the superheat con-
troller is too slow to adapt to the change.
• Compensation for compressor change is done with
KpTe in this case KpTe can be adjusted to be 20% high-
er.
Missing valve capacity.
• Check if valve OD is close to 100 %, if so, the valve is
missing capacity, check if sub cooling is OK.
• System might have loss charge.
Measured Superheat is low-
er than reference - lower 3K
SH close parameter is disabled or not setup optimally.
• Enable the SH close function and set the setpoint 2K
below the reference.
Compressor capacity has changed, and the superheat con-
troller is act too aggressive to adapt to the change.
• Compensation for compressor change is done with
KpTe in this case KpTe can be adjusted to be 20% lower.
9
Fluctuating superheat
The S2 sensor not in good contact with the suction line.
• Check proper mounting of the temperature sensor.
Fast change in load and ambient condition.
• Wait for the stable condition and check again.
Periodic ash gas at the valve inlet.
• Secure stable sub cooling
Aggressive gain Kp and Kp Te parameter.
• Decrease gain in the controller, ex set SH Tn to be 20 %
higher and reduce Kp 20%, if still SH is uctuating, re-
duce KpTe by 20%.
• Try with the higher SH reference.
10
Negative superheat
Wrong sensor type, refrigerant type, pressure transmitter
type and range.
• Check the related setting and range.
During start up suction pressure is low because of low Am-
bient temperature.
• Check the startup problem.
System is not running.
• Check the system.
© Danfoss | Climate Solutions | 2022.06 BC398828796060en-000101 | 77
Superheat controller, Type EKE 1A, 1B, 1C, 1D

Danfoss EKE 1C Specifications

General

Brand	Danfoss
Model	EKE 1C
Category	Controller
Language	English