Hi there,

I have a fairly large model which uses (many) ZoneHVAC:LowTemperatureRadiant:ConstantFlow components. Basically, the model starts warming up but then gives a multitude of warnings along the lines of:

** Severe  ** Temperature (high) out of bounds (340.38] for zone="THERMAL ZONE: A O6 020-021-022-023", for surface="FE-O6-022-LUEFTUNG-SUED"
**   ~~~   **  During Warmup, Environment=RUN PERIOD 1, at Simulation time=12/18 08:21 - 08:24
**   ~~~   ** Zone="THERMAL ZONE: A O6 020-021-022-023", Diagnostic Details:
**   ~~~   ** ...Internal Heat Gain [2.500] W/m2
**   ~~~   ** ...Airflow Network Simulation: Nominal Infiltration/Ventilation/Mixing not available.
**   ~~~   ** ...Zone is part of HVAC controlled system.

The corresponding surfaces do not have embedded LowTemperatureRadiant components. It is entirely unclear why such high temperatures should result. The run period is in December, so outside temperatures are around 0 - 5 °C. In the end, on MacOS, the model crashes with an extreme (window) temperature. On Windows, it struggles on for some time.

Any ideas would be appreciated, as such behaviour would seem to point to model issues.

Thanks. Best, Achim