I forgot the password, how can I reset the PowerDIN 4PZ to factory defaults?

To reset the device to factory defaults, lift the top plate and press the button underneath it. Hold the button pressed and plug in the device. Keep the button pressed. About 10 seconds after powering up, the green LED flashes 3 times and factory default settings are restored (Load to defaults).

For the current procedure, see the supplied QIG (Quick Installation Guide) for the product.
It is available for download at this page, and a hardcopy may be included in the product package.