How to solve “Component disconnected” error in DesignBuilder for Fan Coil Unit and Zone Group?

edit

Hi,

I’m modeling a data center baseline in DesignBuilder v7.3 and get this error:

Building 1 – Component disconnected: BLOCK1:SERVERHALL Fan Coil Unit
Building 1 – Component disconnected: Zone Group
Building 1 – Error in HVAC definition

Setup summary:

CHW loop with chiller and condenser loop with cooling tower.

Office-Control zone: FCU connected to CHW loop.

Server Hall zone: also FCU (currently).

UPS-Service zone: separate system (PTAC).

Zone group created for Office + Server Hall.

Everything looks connected, but simulation fails with these disconnection errors.

👉 Should the Server Hall use a Water-to-Air Heat Pump linked to the Condenser Loop instead of FCU? Or is there another common cause for this issue?

Thanks!