The bumblebee is an ECM pump where the control is designed to have a fixed dT (20F for example) which means that if you have 2 or 3 or more zones with zone valves, the pumps will increase or decrease the flow rate to provide the constant dT. The power it uses will decrease as needed. A regular pump will have a much higher power demand under a lot of these conditions. The Grundfos Alpha is similar except that it tries to match a design pressure drop instead of dT. This may be more important in Europe where they sometimes use really small copper tube to go to radiators (such as 5mm tube). We don't do this. I have used lots of Alpha pumps but it is my first time using this pumps so we will see how it will work.
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