Will a 24 volt buzzer work with 19 volt supply lines?
I did happen to email them at the same time I asked here.  They said it has a tolerance of +10% to -20% so 19.2% would be the minimum so it will just miss and likely fail to power the coil.
Home Depot sells 16 vac buzzers and I just found an 18 vac buzzer so I will look into these.  Thanks for responding.