When modeling Packaged Multi-Zone Systems (System Type = Packaged MZ), the DOE-2 engine does not allow the use of a Water Cooled Condenser. This is a limitation of DOE-2, so you must either choose a different system type or remove the Water Cooled Condenser.
At the System level of the Building Tree, click on the Central System, this will take you into the Central System library. You can now select a different system, or edit the current system. You can change the System Type to another system, or navigate to the Cooling tab and change the Condenser Type to another choice.
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