I had a manufacturer supplied Cal
pump running an a/c 17 yrs ago. The motor is in an oil
bath and is magnetically coupled to the pump. They definitely run very hot. Mine got so hot that the oil
expanded and separated the motor housing from the case, spilling oil in the bilge
and destroying the pump. They are definitely meant to be submerged. Not sure why a/c manufacturers supply them with their units... I switched to a Little Giant pump and it's been doing fine for 17 years! It's 20 gpm and runs 3 a/c units (54K BTU's combined). Has a conventional a/c motor, fan cooled. Pump impeller is magnetically coupled.