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?
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.