If your system uses an effluent pump operated by a float switch a simple check for a stuck float could get the system working again. If not you need an electrician.Your electrician will probably check for power at the ATU system pump or effluent pump or sprinkler pump and work backwards ...
Check the pressure switch with a voltmeter when the pump is running. If the switch is open (O.L.) when there is pressure in the system, replace it. Oil Level Switch Corrective Action: Remove the oil-level switch from the gearbox. While you move the float from position [2] to position...