TR4 and TR5 are fully level controlled. The sight glass of each device is divided into three operational zones. When the level reaches the yellow zone (Yellow) the TR starts filling after a time delay of 10 sec. A further level drop to the red zone (Red) will switch the alarm relay after a time delay of 20 sec / 120 sec.Operating Condition / StatusFunctionContact PositionLEDSupply power is off or normal oil level (<50%)OKBK-BU closeBK-BN openGreenOil Level (close 40%)InjectionGreen,YellowOil Level < 40%InjectionYellowOil level too low < 30%Alarm +InjectionBK-BU openBK-BN closeRed,Yellow