Parallel pumps can be modeled by inserting a pump on different pipes that have the same From and To Nodes. Pumps in series (one pump discharges directly into another pump's intake) can be modeled by having the pumps located on the same pipe. The following figure illustrates this concept:

If the pumps are identical, the system may also be modeled as a single, composite pump that has a characteristic curve equivalent to the two individual pumps. For pumps in parallel, the discharge is multiplied by the number of pumps, and used against the same head value. Two pumps in series result in an effective pump with twice the head at the same discharge.

For example, two pumps that can individually operate at 150 gpm at a head of 80 feet connected in parallel will have a combined discharge of 2·150 = 300 gpm at 80 feet. The same two pumps in series would pump 150 gpm at 2·80 = 160 feet of head. This is illustrated as follows: