I'm working with OpenStudio v2.6 / EPlus V8.9. I'm setting up a primary only, variable flow chilled system with two water-cooled chillers configured in a series arrangement (upstream/downstream). I have a single air-side system attached to this loop and have night cycling disabled (system should operate ~12 hours/day).
The chilled water pumps function as expected, but what I've noticed is that the condenser water (cw) pumps run continuously during all operating hours. I have discovered that this is entirely driven by the series arrangement of the chiller evaporators. When I switch the chillers to a traditional parallel arrangement the cw pumps work properly. Here is the cw pump operation when in series:
I have the cw pumps operation set to 'intermittent' and I have a minimum flow of '0'. Adding a bypass pipes does seem to impact this result in anyway. The impact on the cw pump seems be be defined entirely by the evaporator side of the system with the chiller condenser arrangement having no impact. I have verified that AHU coil has no load and also verified that the chillers shutoff:
Has anyone else seen this issue?
