The Goodman CAUF Uncased Upflow/Downflow Indoor Coils are made for split system air conditioners and heat pumps. This evaporator coil operates with an air conditioner or heat pump of two different tonnages, the evaporator coil comes factory equipped with an orifice (Flowrater) for the small listed tonnage. If you are matching the evaporator with an air conditioner or heat pump of the higher tonnage, the Flowrater of that tonnage will need to be used. If a new Goodman air conditioner or heat pump is purchased together with the evaporator coil, the correct Flow rater will be provided with that unit. If you are just purchasing this evaporator and are going to match it with a unit of the higher tonnage listed on the description, you will need to purchase the larger Flowrater and install it in the evaporator before start up.