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Kevin Thigpen

Technical Services Manager North Alabama District

How to Wire and Check a Dissipation Board

In our last article, Understanding Active Dissipation, we covered the basic reasons why a system may have a refrigerant leak and how the board will operate during dissipation mode due to that leak. This month we will take a deeper look at how to properly wire {install} and troubleshoot the sensor itself on the FJ fan coils.

To be able to accurately troubleshoot anything, you must know where to start. The dissipation board pictured above, resides between the main board and the thermostat. This allows the dissipation system to actively control the unit during a dissipation sequence. This occurs starting at the wiring for the 8-pin plug on the dissipation board.

In the picture below is the proper wiring setup and color codes for each pin.

Note on communicating units: wires 3-7 will not be used. Only wires 1, 2 and 8 will be connected.

Next is the Dissipation Sensor. The sensor is a 4 pin 5vdc sensor with an 8ft harness. The sensor will be factory mounted in all fan coils and SPPs. The sensor will be located in the case coil boxing. If a cased coil is being installed, the sensor is NOT factory installed but does come included. Please be sure to check all packing materials to ensure the sensor and harness aren’t accidentally discarded.

Troubleshooting the harness connections is simple using the picture below to check for the proper 5VDC signal.

Dissipation error code table:

This information should help with wiring and checking your dissipation board and sensor. Depending on the equipment, wiring may differ depending on the options being installed. Check both installation and service manuals for the equipment you are working with to verify proper wiring and functionality of the dissipation safety system.

Should you have any questions, please feel free to reach out to your local Mingledorff’s for help.

Disclaimer: The technical statements, information and recommendations contained herein are believed to be accurate as of the date hereof, but Mingledorff’s does not make representations or warranties, express or implied, as to its accuracy, its completeness, or the results to be obtained. The information is being provided for informational purposes only and is intended for use by persons having adequate skill and expertise regarding the proper selection, use and application of the products and recommendations and at their own risk and discretion. 

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