Running Pentair Intelliflow Pumps in Parallel

[mas985]

When you run two pumps in parallel on the same plumbing, you don't get anywhere close to twice the flow rate. This is because the head loss seen by each of the pumps is due to the combined flow rates. For example, on typical 2" plumbing, dual pumps will increase the flow rate by only 6% but the energy consumption increase by over 2x so efficiency is much worse. Compare that to increasing the RPM of a single pump by 6% for a 6% increase in flow rate, the energy increase is only 9%.

The most efficient way to increase flow rate is with RPM.

Here is the effective head loss curve with two pumps in parallel and at two different speeds. The parallel pumps (noted by (P)) has the head curve extended to the right but max head does not change. I also plotted plumbing Curve-C over the head curves so you can see how the operating point changes for a single pump to a dual pump.