I have a two-story house with a hydronic heat pump serving a downstairs radiant floor zone and an upstairs radiant ceiling panel zone. The physical configuration is such that the floor and ceiling loops are in series, with a 3-way valve after the floor loop that returns to the heat pump. So, either if both zones or just the 2nd floor zone is calling water will be delivered through both loops; however, if just the 1st floor zone is calling, water will only be delivered through the floor loop.
I have this modeled as (2) ZoneHVAC:LowTemperatureRadiant:ConstantFlow objects with the branches set up so that there's a splitter after the radiant floor that splits to either the radiant ceiling or a bypass back to the heat pump. However, this isn't working as I intended. In cooling mode, the ceiling loop will operate independently, and no water is flowing through the floor loop. In heating mode, which is even odder, the ceiling loop never calls for heating and appears to be a slave to the floor zone and remains outside of setpoint until the 1st floor calls for heating. Any thoughts on 1) what I'm doing wrong and 2) how to control the model to reflect the actual design?
Thanks.