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Is it possible to model two or more separate Variable Speed Pumps (VSPs) that discharge to the same system but only one turns on at a time?
When trying to do this, the VSPs may appear to not respect the controls, or various errors may occur including:
"Unable to solve network hydraulic equations""Variable speed pumps not in parallel cannot be controlled by the same control node."
By default, if multiple VSPs are considered in parallel (based on proximity of a common downstream node), then special logic takes over which pump turns on; a "lead" pump turns on first, then a second "lag" pump only turns on if the lead pump cannot achieve the desired target within the specified maximum relative speed factor. If you have a system where separate variable speed pumps control the same downstream system yet only one turns on at a time, the following tips may help you model this:
Modeling variable speed pumps in parallel with different pump curves
Modeling fixed head parallel VSPs that have different head values
How do I model parallel fixed head (target head) variable speed pumps that are controlled by flow in a downstream pipe?
Can you run a VSP with a control node and logical controls at the same time?