I am trying to model a system that has hot water boilers and heat pumps on the same loop. The hot water loop has an OA reset from 110 F to 180 F. When the temperature drops below 130 F, the heat pumps are supposed to kick in to provide heat to the loop. I have the heat pumps set up as loop-to-loop heat pump chillers. The hot water temperature has an OA reset schedule and I have load management based on OA set up. However, this is not working. I am getting an error saying that that the design temp of the chiller is to high for a loop-to-loop heat pump (max 130F).

Any suggestions on how to overcome this problem or how to best model this system?

Oleksandra Onisko LEED AP