The probe is packaged with two stainless steel hose clamps. For a pump that is to be installed in a vertical position, clamp it to the drop pipe just above the pump outlet, as shown in the photo. Splice the two probe wires using the splice kit components that are packaged 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 “Low-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.

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/on.

The low-water probe must be positioned vertically, within 10°. If the pump is NOT to be installed vertically, find an alternative way to mount or suspend the probe, so that it is higher than the pump, and in a vertical position.

Do not use a pressure switch with a “low water cutout” or “loss of prime” feature as a method of dry-run protection. A helical rotor pump will maintain pressure as it runs dry, so this method will not work reliably. For pressure switch information, see Section 5.12, Pressurizing Systems. Potential problems with the low-water probe in surface water The probe has a moving float. It is highly resistant to deposits and debris. However, it may stick under some extreme conditions, especially from algae or water creatures (snails, etc.) that may be present in surface water. Possible solutions are:

1. Hang the probe independently of the pump and pipe (clamped to a weight, but not to the drop pipe). This way, it can be pulled up for inspection or cleaning without the need to pull the pump. (This may not be feasible if the well casing is smaller than 6".)
2. Pull the probe out periodically (with the pump if necessary) for testing and inspection. The pump should stop at the moment the probe leaves the water.
3. Wrap the probe in a protective screen (fiberglass window screen, for example). Substitute a different type of float switch. You can use any switch that makes contact on rise (normally open). Low-water probe installed in the standard position, for a pump that is positioned vertically