Error in Buildings.Zones.ZoneTemplateAirvolumeMixed

[jmoeckel]

Running the following commands with Dymola 2017 FD01

Advanced.PedanticModelica=true;
checkModel(BuildingSystems.Buildings.Zones.ZoneTemplateAirvolumeMixed)

returns the following error:

The model BuildingSystems.Buildings.Zones.ZoneTemplateAirvolumeMixed component radiationDistribution is structurally singular.
when assuming the most generic outside couplings to all the flow variables of its connectors.

[thorade]

Dymola 2018 attempts to further localize singularity:

Attempting to further localize singularity.

Singularity of BuildingSystems.Buildings.Zones.ZoneTemplateAirvolumeMixed is in the component radiationDistribution, class BuildingSystems.Buildings.BaseClasses.RadiationDistribution.

The model BuildingSystems.Buildings.Zones.ZoneTemplateAirvolumeMixed component radiationDistribution is structurally singular.
when assuming the most generic outside couplings to all the flow variables of its connectors.

Some connectors are not connected from the outside:
radiationDistribution.toSurfacePorts