I've got a project where a central hot water / boiler system serves
several secondary loops...one is a domestic hot water loop, but most are
hot water heating loops. When I assign the DHW loop to the primary
loop, it forces me to change it to a "hot water" type circulation loop.
This would be fine, since I can just establish a process load under the
DHW loop and keep it as a "hot water" loop....however, I'm getting
errors about no flow in the DHW secondary loop, even though I currently
have a specific GPM assigned to the loop for 24 hrs a day, 365 days a
year.

Is this error related to the fact that there is no actual connected load
to the loop, other than a process load? In other words, does the loop
HAVE to have some sort of return water volume to justify it as a "loop"?

Has anyone ever gotten around this?

Thanks for any advice

James Hansen, PE, LEED AP