Manual Mode - Danfoss EKE 1A User Manual

Superheat controller, Type EKE 1A, 1B, 1C, 1D
Figure 83: Minimum S4/leaving media
S3
T
"Warm" brine / water
S4
T
"Cooled" brine / water
 NOTE:
An undershoot below the Min S4 is possible, so a frost protection is still needed to secure that the compressor is
stopped before the braze plate heater is destroyed by ice.
Table 45: Minimum S4/leaving media parameter table
Parameter
N126
N127
Priority of Protection features:
To overcome conflicts between different limiters, a priority function is implemented as follows:
1. Superheat close (it is always important to avoid liquid back to the compressor)
2. LOP (Low operating pressure)
3. HCTP (High condensing temperature protection)
4. Min. S4 (Minimum S4 temperature)
5. MOP (Maximum operating pressure)
As an example, if the pressure is low and at the same time the superheat is low. LOP control would like to open the
valve to raise the pressure. but SH close will decrease the flow to regain a safe superheat. In this case the LOP
demand is overruled by SH close. So, in the end if the conflict still is active the mechanical low-pressure switch will
need stop the compressor.

6.3.3 Manual Mode

In the manual mode, the user can select actions based on signals from digital inputs DI2/DI3. In the manual mode
we can use 4 different options:
1. Manual OD from preset parameter via DI
2. Manual control of Relay
3. Manual control Valve
4. Manual Homing
 NOTE:
Too often use of Manual Homing could wear out the valve. For normal operation use overdriving feature.
Manual OD When DI 2 is configured as Preset OD, the valve OD will be positioned as defined by valve OD parameter
[I078 - Preset OD].
Table 46: Manual OD
Digital input O022 DI2 configuration
O037 DI3 configuration (only in
EKE 1A)
Manual Preset via DI 078 Preset OD
When manual mode becomes active, the state of alarm output will remain the same and be transferred to the
parameter(s) for Manual relay DO1. When manual mode becomes inactive the actual state of Manual relay DO1 will
be the starting point for the next mode.
© Danfoss | Climate Solutions | 2022.06
p0 S2
R T
°C
S3
Plate heat
exchanger
S4
S4 min
S4 min
EEV
Electric expansion valve
Function
Min. S4 mode
Min. S4 setpoint
2 = Preset OD
2 = Preset OD
desired Valve OD %
Time
Description
0 = Off | 1 = ON
Minimum S4 (media outlet) protection setpoint
BC398828796060en-000101 | 57