Variable speed circulator pumps usually have three settings on which they can operate. This means they will have three different pump curves and can be used for a larger range of applications. Variable speed pumps are advertised, rightfully so, as an inventory reducer – meaning that contractors can carry them on their truck to use in a variety of jobs.
This is true, but we would advise a certain amount of caution. The three curves on a variable speed pump are almost always very similar: one central curve with the others slightly above and slightly below it. If an application calls for a flat-curved pump (high flow, low head), then a steep-curved variable speed circulator (low flow, high head) will not work – regardless of the setting. SupplyHouse.com stocks variable speed pumps from Taco, Grundfos, Bell & Gossett, and Wilo.
