How to Program an NFC Control Board
October 15, 2025
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When replacing a control board equipped with Near Field Communication (NFC) capabilities, it’s critical to ensure that the new board
With the changing of the new refrigerant, new controls have been added for safety incase of a refrigerant leak, the Refrigerant Dissipation Board (RDB). This board has 13 flash codes but number 13 is the one that is going to be discussed. Different main control boards will connect to the RDB differently. The equipment that uses a Unit Control Board (UCB) will be discussed in this information. Some of the units are the 40RLA commercial fan coils and 50FEQ RTU units, these are just a couple that use the UCB board with the dissipation controls.
The flash code 13 description is the (Fire / Smoke Override / G input signal is lost. Indicates another unit safety will override dissipation). What actually happens is the RDB looses 24 volts to the board on connection 6 where the J1 connector plugs onto the RDB. There are several things that can cause the loss of 24v to this connection on the RDB. The 24v that leaves the transformer and travels into the UCB board through the main connector will go through the smoke detector, phase monitor, fan limit switch and safety relay built into the Eco Blue motor or the safety switch on the VFD drive on larger units. This path is also known as the safety chain circuit, if any of these controls interrupt the path of the 24v it will kill 24v to the UCB and not allow the unit operate and trigger the flash code 13.
If you get a call to a commercial job and the thermostat is blank and the RDB is displaying the 13-flash code. Look for any safety device that could have interrupted the 24v path that sends the 24v to the RDB connection 6 in the J1 connector. Also remember that the safety circuit in the Eco Blue motors and VFD drive is only closed when they have power.
Sources:
40RLA/S/Q 07-12, Installation, Start-up & Service Instructions / 3-2025
40RLA/Q/S*14-30, Installation, Start-up & Service Instructions / 3-2025
50FEQ*04-07, Installation Instructions / 11-2024
50FEQ*17-28, Installation Instructions / 7-2024
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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