Simple Installation

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System Operation

Following power-up, the status LED will alternate colors between GREEN and YELLOW at a .5 second rate to indicate that the SDK is synchronizing itself with the refrigeration system. This pattern is maintained until a termination of defrost is observed. The status indicator color then changes to Yellow.
The sensor LEDs will be GREEN if the sensor is functioning properly and RED if the sensors are not functioning properly.
If the sensor color is RED, check the connection to make sure that it is seated properly on the control module. Also check the wire harness connection at the pressure transducer.
If the connections are in place, you will need to replace the sensor.

LED Status Indicator Lights

• GREEN = No defrost was necessary, defrost was skipped
• YELLOW = Defrost was necessary, defrost occurred
• RED = Control module failure. You will need to replace the module. When the status LED is RED, the skip defrost output will not activate, but system will continue to operate normally.

It’s that easy to install.

In 6 easy steps and about 30 minutes*, your refrigeration system will be smart and saving you money.

System Requirements

Refrigeration systems with electric defrost heaters
Defrost control voltage must be 230 VAC, 50Hz or 60Hz
System must have an electro-mechanical time clock that contains a contact closure reset input for defrost termination

For Best Results:

Defrost time clock should be programmed for three or more defrosts per day
Defrost set to terminate normally on coil temperature
Optimal performance on systems that have daily varying loads

* an experienced contractor should be able to install in about 30 minutes.


1. Turn off the refrigeration system and mount the SDK control module inside the electrical panel.

2. Connect the six wires* as shown on the wiring diagram to the right. Four wires attach to the time clock and two connect to the compressor contractor coil.

3. Install the suction pressure transducer onto the Schrader fitting using the Schrader “T” provided.

4. Install temperature sensor onto side (90°) of suction line and insulate.
5. Verify correct wiring: turn on power to unit without the temperature or pressure sensors connected. • Examine the status LED indicator: if the status LED color matches system mode correctly, the wiring is correct. Blinking Red: System is in defrost mode Blinking Green: System is in cooling mode Blinking Yellow: System is off

6. To activate the SDK: turn off power, connect sensors to the module, turn on power. Turn on the power and start SAVING MONEY.