Danfoss EKC 361 Media Temperature Controller

Wiring and Connections

Necessary Connections

The following connections are required for the EKC 361 controller:

• Terminals 25-26: Supply voltage 24 V a.c.
• Terminals 17-18: Signal from actuator (from NTC)
• Terminals 23-24: Supply to actuator (to PTC)
• Terminals 20-21: Pt 1000 sensor at evaporator outlet
• Terminals 1-2: Switch function for start/stop of regulation. If a switch is not connected, terminals 1 and 2 must be short-circuited.

Application Dependent Connections

Additional connections depend on the application:

• Terminals 12-13: Alarm relay (connected in alarm situations or when controller is dead)
• Terminals 8-10: Relay switch for fan start/stop
• Terminals 9-10: Relay switch for solenoid valves start/stop
• Terminals 18-19: Current signal from other regulation (Ext.Ref.)
• Terminals 21-22: Pt 1000 sensor for monitoring
• Terminals 2-5: Current output for Sair/Saux temperature or ICAD actuator for ICM valve
• Terminals 3-4: Data communication (requires a data communication module to be mounted)

Data Communication Wiring

For data communication, observe the following cable length recommendations:

• Cable length less than 25 m: 0.75 mm²
• Cable length between 25 m and 75 m: 1.5 mm²
• Cable length greater than 75 m: 2.5 mm²

Wiring Diagram Description

A typical wiring diagram shows the EKC 361 controller connected to components such as ICS, ICM, CVQ, EVRA, and temperature sensors (Pt 1000 AKS 21). It illustrates the flow of power and signals for system operation.

Operation and Display

Display and Indicators

The controller displays values with three digits. The temperature unit can be set to °C or °F. Front panel LEDs indicate relay activation. The three lowest LEDs flash if an error occurs in the regulation. Error codes can be displayed, and alarms cancelled by briefly pressing the uppermost button.

Controller Messages

The controller may display the following messages:

• E1: Error in controller
• E7: Sair cut-out
• E8: Sair short-circuited
• E11: Valve actuator temperature outside its range
• E12: Analog input signal outside its range
• A1: High-temperature alarm
• A2: Low-temperature alarm

Using the Buttons

Two buttons are used to adjust settings, increasing or decreasing values. To change a setting:

1. Access the menu by pressing the upper button for a few seconds.
2. Navigate through parameter codes using one of the buttons.
3. Press both buttons simultaneously to select a parameter.
4. Press one button to change the value.
5. Press both buttons simultaneously to save the new value.

Example: Setting a Set-point

1. Press both buttons simultaneously.
2. Use one button to select the new value.
3. Press both buttons again to confirm the setting.

Example: Setting Other Menus

1. Press the upper button until a parameter is shown.
2. Use one button to find the desired parameter.
3. Press both buttons simultaneously until the parameter value is shown.
4. Use one button to select the new value.
5. Press both buttons again to confirm the setting.

Menu Overview

* This setting is only possible if a data communication module is installed.

Performance Graphs (n01 and n02)

These graphs illustrate the relationship between evaporating temperature and actuator temperature. Parameter n01 is set for the highest regulated room temperature, requiring a +10 K offset from the curve due to actuator tolerances. Parameter n02 is set for the lowest suction pressure, requiring a -10 K offset from the curve.

CVMQ Valve

Graph showing Pressure (bar eff.) vs. Temperature (°C) for CVMQ valves, indicating 'Open' and 'Closed' actuator states for different refrigerants (R22, R134a, R404A) and pressure ranges (-1-5 bar eff., 0-6 bar eff., 1.7-8 bar eff.).

CVQ Valve

Graph showing Pressure (bar eff.) vs. Temperature (°C) for CVQ valves, indicating 'Open' and 'Closed' actuator states for different refrigerants (R22, R134a, R404A) and pressure ranges (-1-5 bar eff., 0-6 bar eff., 1.7-8 bar eff.).

KVQ Valve

Graph showing Pressure (bar eff.) vs. Temperature (°C) for KVQ valves, indicating 'Open' and 'Closed' actuator states for different refrigerants (R22, R134a, R404A) and pressure ranges (-1-5 bar eff., 0-6 bar eff., 1.7-8 bar eff.).

Startup and Troubleshooting

Startup Procedure

After electrical connections are made, follow these steps to start regulation:

1. Switch off the external ON/OFF switch that starts and stops regulation.
2. Follow the menu overview and set parameters to desired values.
3. Switch on the external ON/OFF switch to start regulation.
4. If a thermostatic expansion valve is fitted, set it to minimum stable superheating. Adjust n01/n02 if a specific T0 is required during expansion valve adjustment, and remember to reset them afterwards.
5. Monitor the room temperature on the display. A current signal representing room temperature can be transmitted on terminals 2 and 5. Consider connecting a data collection unit to follow temperature performance.

Temperature Fluctuations (Oscillation)

If the system oscillates after achieving stable operation, adjust parameters based on oscillation periods and integration time (Tn).

If oscillation period is longer than integration time (Tp > Tn):

1. Increase Tn to 1.2 times the current Tn.
2. Wait for the system to stabilize.
3. If oscillation persists, reduce Kp by approximately 20%.
4. Wait for the system to stabilize.
5. Repeat steps 3 and 4 if oscillation continues.

If oscillation period is shorter than integration time (Tp < Tn):

1. Reduce Kp by approximately 20% of the scale reading.
2. Wait for the system to stabilize.
3. Repeat steps 1 and 2 if oscillation continues.

Literature and Factory Reset

Literature References

Relevant documentation includes:

• Manual EKC 361 (RS8AE---)
• Installation guide
• Data communication link (RC8AC---)

Factory Reset Procedure

To revert to factory-set values:

1. Disconnect the controller's supply voltage.
2. Keep both buttons depressed while reconnecting the supply voltage.