I have a Hayward VSP that not matter what speed it runs at will drop RPM for a second every few min or so and then go right back to full speed. Its enough if a drop to cause the Heater to report low flow and occasionally the flow sensor as well. I checked the voltage come into the pump and its solid 120V and never drops. I saw no drop in LV single as well. For the life of me I can't find any reason for this to be happening. Grounding is all tight as well. Its on the same circuit as the heater but it does this with and without the heater running.