The label on my central air conditioner looks a lot like this one (photo below). What do the two numbers (separated by a slash) mean for voltage and the three amperage ratings?
The text Volts 208/230 Phase 1 means the device will run on either 208 volts or 230 volts (which is nominally 240 volts).
In the amps section, the separated numbers (which are the same) are the corresponding value for operation on 208 or 230 volts, respectively.
To add to this answer, air conditioners, motors and welders follow different rules than what is considered conventional.
The MCA (minimum circuit ampacity) is what you size your wire by. The maximum/minimum fuse or breaker is what you can size your overcurrent (fuses or circuit breakers) by. So this unit, having a 19A MCA, can be wired with #12cu wire, and must be fused or breakered at 25 or 30A.
YES, I AM saying you can put #12 wire on a 30A breaker.