After delivery power
We often discuss with our suppliers the relevance of the capacity of machines with diaphragm and piston pumps. By myself, at 20 degrees temperature, can not detect any difference between a diaphragm pump with 5.9 liters/min to a piston pump with 6.1 liters/min. Both results in a perfect spray pattern.
However, I have to admit that the piston pump, especially with a hydraulic drive, is the better choice for difficult temperatures or materials. It just has more power. Nevertheless, we sell 8:2 small road marking machines with diaphragm pumps in Central Europe compared to piston pumps. Handling, maintenance and costs are out of proportion.