I have 8 watering pumps that I use to teach kids to code with the M5s. Two of them do not work. Water does not flow, event though they make a noise. I tested all Watering units with the same Core2 on the same Groove port (B).
There is one difference that I can tell. When I blow through the inlet of working pumps - air gets out on the other side. When I do the same on the "broken" pumps no air comes out on the other side. This makes me think there is something blocked. Its a fresh pump that I ordered a while ago so it should not have gotten any dirt in it.
Is there anything I can do to get them to work? Anybody else with the same experience?