User Notification "More than one VSPB cannot control the same control node"

  Product(s): WaterGEMS, WaterCAD
  Version(s): 10.XX.XX.XX, 08.11.XX.XX
Area: Data Input and Layout


I am getting a user notification that says "More than one VSPB cannot control the same control node". I'm following all the rules for variable speed pumps, what am I doing wrong?

Problem ID#: 67011


It's likely that a regular pump set up as a VSP was meant to be used here instead of a VSPB. VSP's are setup using the regular pump element of which you will just set the properties of this element to variable speed pump. You do this by changing the "Is variable speed pump?" field to 'True' and then setting up your pump. VSPB's are the element that looks like a pump with a square around it. A Variable Speed Pump Battery element represents multiple variable speed pumps that meet the following criteria:

1) the VSPs are parallel with each other (not in-line)
2) the VSPs are sharing common upstream (inflow) and downstream (outflow) nodes
3) the VSPs are identical (have the same pump definition)
4) the VSPs are controlled by the same target node and the same target head.

Parallel variable speed pumps (VSPs) are operated as one group and led by a single VSP, called the lead VSP, while the other VSPs at the same battery are referred as to as lag VSPs. A lag VSP turns on and operates at the same speed as the lead VSP when the lead VSP is not able to meet the target head.

From the standpoint of input data, Variable Speed Pump Batteries are treated exactly the same as single pump element that is defined as a variable speed pump of the Fixed Head Type with one exception; number of Lag Pumps must be defined in the Lag Pump Count field.

See Also

Modeling multiple VSPs where only one turns on at a time

Modeling fixed head parallel VSPs that have different head values

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