1. Introduction

Each Water Level Meter (Dipmeter) comprises a chrome plated brass sensor probe fitted to a graduated cable, wound on a reel containing a transistorised switching circuit, audio and visual indicator, sensitivity control and battery.

The sensitivity control is factory adjusted to suit the water conductivity of purified water; under normal conditions no user adjustment is required.

If the Water Level Meter is to be used in salt or brackish water the sensitivity control may need to be adjusted to enable correct functionality.

This article outlines some of the issues that may occur when using a Water Level Meter, why they occur and what will need to be done if these issues are apparent.

Figure 1. Soil Instruments Water Level Meter

2. The unit is producing a continuous beep after being submerged

If after the probe has been submerged in water and then removed from water, the buzzer continues to buzz, there is a chance that your borehole water contains salts lowering its electrical resistance and therefore making it easier to conduct electricity.

If this occurs adjust the sensitivity more towards the ‘low’ sensitivity position and reattempt reading. It may be necessary to clean the probe to remove salt or hydrocarbon products before making the adjustment.

To adjust the sensitivity of the probe unscrew the three fixing screws from the reel front faceplate and carefully lift away to expose the wiring, battery and circuit board.

Take care not to damage any of the wiring.

Alternately raise and lower the probe through the surface of water either within the standpipe or a container whilst adjusting the sensitivity control using a small, flat-bladed screwdriver (Figure 2.) until the output signal, when the probe is in the water is definite and quite distinct

Figure 2. Adjusting the sensitivity of the probe

3. The buzzer is not reacting to the probe being submerged

If the buzzer and/or LED are not activating when the probe is submerged in water there is a strong possibility that the battery within the reel hub has dropped below a sufficient voltage to power the buzzer and will need replacing.

To do so you will need to unscrew the three screws on the front of the hub, take care not to damage any of the wiring.

Ensure you have a new ‘PP9’ 9V battery to hand. The battery is secured by a cable tie attached to the battery.

Carefully cut the cable tie and withdraw the battery. Insert a new battery observing the correct polarity and replace the cable tie.

Carefully replace the faceplate ensuring that wires are not trapped and re-tighten the three fixing screws.

Warning: We strongly recommend re attaching the new battery using a new cable tie or ensuring that the battery is safely secured using a different adhesive.

If the battery is not secured you will risk damaging other internal components when using your instrument.

If you are sure that the battery does not need replacing, or you have replaced the battery and you are still not receiving a reaction from the buzzer when the probe is in the borehole, however under running tap water it does buzz, we would recommend adjusting the sensitivity of the probe as described in section 2.

This can occur when borehole water is too hard and/or pure to conduct sufficient electricity to trigger the probe circuit.

If this does not solve the problem we would recommend visually inspecting the tape to see if any damage has been incurred. Possible damage to the cable includes 'nicking' the tape on a sharp object or stretching of the tape causing the tape to split, resulting in a broken circuit.