Don't confuse service factor with efficiency. 2 speed pumps deliver less HP per watt on low speed. Pump laws dictate that double the flow requires a CUBE in HP. The optimum solution would be to have and ECM or 2 seperate pumps. ECM's have a HUGE reduction in power when GPM is reduced, since they aren't based on simply increasing the "slip" of the motor. Same with 2 pumps, the smaller pump only uses a fraction of what the "cleaning pump" would use. It's just a matter of weighing energy costs vs. upfront motor costs.
Another option is switch to time of use power rates if your utility offers it. Run pumps when power costs less. No upfront equipment costs !!
|