The F24 fault code indicates a problem in the water temperature sensor. Also, the heating circuit may need to be checked. In other words, you need to check the sensor itself and the wiring harness and connections.
Unplug the washer and remove the bottom panel. To ease access to the screws, put pads under the washer’s front feet. Pull the panel down and off. The sensor looks like a small square plug placed between the heating element’s terminals near the base of the wash tub at the heating element’s front. Check this plug and make sure it is plugged well. It often gets loose because of vibration. Also, check all pins and contacts for rust. If there is nothing wrong with it, disconnect the wire harness and check resistance. See the temperature meter readings:
32°F (0°C) 35.9 K ohms
86°F (30°C) 9.7 K ohms
104°F (40°C) 6.6 K ohms
122°F (50°C) 4.6 K ohms
140°F (60°C) 3.2 K ohms
158°F (70°C) 2.3 K ohms
203°F (95°C) 1 K ohms
it should be about 9K ohms. If necessary, take a closer look at the connector and make sure it is not oxidized or rust. Clean the plug and check the screen. If the error code appears again, you may need to check the sensor. If it is bad, replace it. If it is good, measure the heating element terminals’ ohmage. It should read 15 ohms.
Finally, you can remove the top panel. Undo the three screws that are holding it at the back. Push the panel back and off. Resistance-check the main control board, which is located behind the wash tub. Check the heating element’s solenoid. To do so, remove Connector 9 from the main control board (the second one on the right as you look at the unit from the front). Test points 1 and 2 should read 15 ohms as well.