Lorentz Well Probe



Dry Run Bore Hole Protection

Low Water Sensor Probe for Dry-Run Protection in HR Submersible Pump Systems




Low Water Sensor Probe for Dry-Run Protection in HR Submersible Pump Systems


The purpose of the probe system is to sense the loss of water and turn the pump off before it can run dry. The probe is packed with two stainless steel hose clamps. For a pump that is to be installed in a vertical position, clamp it to the pipe just above the pump outlet. Splice the two probe wires using the splice kit components that are packed with the probe. The assembly procedure is the same as the main pump splice. If you are NOT using the well probe, it must be bypassed. Connect a short wire between the probe terminals in the junction box (terminals 1 and 2). Do this only if you feel certain about the reliability of the water source. Wire size: #18 AWG ( 1mm2) or larger.

Principle of Operation:

The probe contains a mechanical float with a magnet inside. When the probe is submerged, the float rises, and the magnet actuates a switch. The switch closes (makes contact) to indicate the presence of water. The switch is sealed, so the contacts never touch the water. If the water level drops below the probe, the float drops, and the switch opens (breaks contact). The controller will stop the pump and the &ampldquoLow-Water OFF” light will indicate. When the water level recovers and switch closes again, the controller will delay the restart for 20 minutes. This gives time for the water level to recover. To force a quick restart, turn the controller off, then on again.

NOTE Pumps made before October 2003 may have a different type of probe, with wet electrodes. Either type can be used with the PS-XXX series controllers. The Low Water-OFF light flashes slowly for the remainder of the day, even if the water recovers and the pump restarts automatically. This tells you that the water source ran low at least once since the power was disrupted (or sun went down). To turn the light off, reset the controller by turning it off and back on.