I have a three vessel HERMS setup using two of your 24v Topsflow pumps with speed control boards. Each has its own 24v power supply.
All has been working well until today when during a brew I noticed that the pump used for recirculating the mash was barely able to move the fluid. Swapping power with the second pump just transferred the problem to that pump. So it seems both pumps are good.
I have checked the voltage values across the terminals and red/black on both boards is 24v, on the problem board between the signal wire(blue) and black I only get 1.6v even when on max. The other board registers 4.9v on max. I have also swapped the individual 24v sources around but this makes no difference to the problem board.
Have I missed something or is this board failing/failed?