Turns out it isn’t app based. It’s tone-based, like a fax tone. It’s only to be used when contacting an LG service centre if the machine is faulty. At some point the tech will ask the user to hold the phone near the power button then turn the machine on & press the temperature button for 3 seconds. A series of tones are sent to the service centre which deciphers them and reveals the reported problem to the service centre.