2.5 tons
That isn't a typical Rheem model number, are you sure that isn't the serial? If it is the model number it is a 2.5 ton :)
WHAT IS A RHEEM rajb-031jaz
5 Tons
2
five ton
5 ton
2 ton
3 ton
5 tons, denoted by the 60 in the model #, (5x12=60).
Your first set of numbers gives you the tonnage, so this is a 2 ton; your "4" number represents a 460-volt electrical requirement
2.5 tons. 1 ton =12,000 btu so 30,000 btu=2.5 tons. The 30 in the model # denotes btu of the unit in 1000`s.