Hello eQuesters,

I am trying to model a two pipe system with a demand operation loop for a
residential building in Maryland. Currently, my two pipe system turns on
cooling when the zones are calling for cooling as expected, however it
never changes over to heating during the winter. It is always either off,
or on very rare occasions cooling, resulting in high unmet heating hours.
Can some one explain how the two pipe system determines when to change
from heating to cooling mode?

I've looked at the zones they are definitely below the heating throttling
range. Does eQuest take a sum of the room loads on the loop to determine
to heat or to cool?

Your help is greatly appreciated.

Thanks!
Justin