Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
If you only made a copy of the Fan:VariableVolume object to create the Fan:ConstantVolume object, but left the VAV fan in the model, then the CAV fan is not connected to any systems ... yet. You need to search for the name of the VAV fan to see where the Branch of an AirLoopHVAC object references that name. Then, replace the Object Type and Object Name input fields of the Branch referencing the VAV fan with the same parameters (object type and object name) of the CAV fan that you created.
You'll also need to make sure the CAV fan is properly connected to the other components that the VAV fan was connected to (the CAV fan should have the same inlet and outlet nodes as the VAV fan).
I would recommend that you begin to use the Fan:SystemModel object. This is the "swiss army knife" of fan object in EnergyPlus -- this one object type can model CAV, VAV, and On/Off Cycling fan types, as well as allow for a different night-time ventilation flow rate and other performance parameters.
