This relies on the fact that at a constant speed, the pressure increases for reduced flow.
There are a number of pumps being used that are "Flat Curve" Pumps where the pressure does not increase much for reduced flow at a constant speed. In this case, the presure transducer approach does not reliably reduce the pump speed when the flow is reduced. Where sleep mode is employed, it is not uncommon for the pump to never go to sleep because the speed deos not reduce to minimum speed.
There are a number of possible approaches to this situation, but I would like to know if anyone has done a good analysis of these approaches and determined which will work the best?