Curtis_H
NAXJA Forum User
- Location
- Central Iowa
I know you said you cleaned the tank before you put it back in, but sometimes heavier grit can get trapped in there and not come out so easily. It is possible that you have grit/slugs in the tank that are being sucked up into the screen when the pump is running and causing it to cavitate, hence the humming noise. they can either cause the pump to overheat and shut down or when enough have been sucked up it can clog the screen and kill the pump. Then, when the pump is off and no vacuum is present at the screen they will float back down and settle away from the pump until the entire cycle starts back up. Check the tank thoroughly with a flashlight, run a magnet on a stick and some reverse wrapped (sticky side out) duct tape on a stick all through the bottom of the tank before you put it back in the vehicle, just to help eliminate this problem.