Odd problem with ATO

[JingoFresh]

I have a JBJ ATO controller.

Works fine, except when I do a water change.

I have it in mode b, which means when water goes low enough that the minlevel sensor goes off, it refills until both the minlevel and maxlevel sensors are on.

Somehow, after a water change, even with it detecting both sensors on, it wants to run the pump.

Has anyone seen this behaviour?

 

[JingoFresh]

I guess it's defective then.

 

[JingoFresh]

Seems like the problem may have been due to the timer and the more powerful pump.

I don't see why it has to activate after a water change, but now that I have bought a very weak pump (3.5gph) it should be OK.