From the TP2 manual:
We've also included a 3-pin fan signal connector. Connect it to one of the fan connectors on your motherboard. You can monitor the speed of the rear power supply fan through your
motherboard BIOS or through the monitoring software included with your motherboard.
Note: When temperatures are low, the speed of the fan many drop below 1000 RPM. At such low speeds, some motherboards may not be able to properly detect the fan speed and may generate a false fan failure warning. To ensure proper fan monitoring, please refer to your motherboard manual.