D2 clamp voltage potentially too low #6
Description
D2 hold-off voltage is 14V. Board net voltage may reach up to 15V in some cases, and disturbances may go much higher than that.
D2 is of type SMBJ14A. This type has a break-down voltage of minimum 15.6V, but that is already at a reverse current of 1A. It will be dissipating more than 15W at that time which it won't survive for long.
Even at voltages much lower than that, significant reverse-current can flow, and D2 may get hot or even burn out.
SMBJ18CA would be a much better suited alternative.