The MultiTrode Liquid Level Sensing Probe hangs in the wet-well by it’s own cable. When specifying the probe, we need to know:

1.       The probe length, which is the effective detection length. Standard lengths are 1.0m (3’), 1.5m (5’), 2.0m (6’), 2.5m (8’) and 3.0m (10’). Custom lengths are also available on request
2.       The cable length, which has to reach from the top of the probe in it’s normal hanging position, to the junction box or control panel.

In most installations, the probe is sized for the “live” depth of the well, the range that the liquid normally covers. The live range is typically only the bottom 25% – 50% or so of the full wet well depth. E.g. if the wet well is 5m deep, but the invert is 3m below ground level, the live range of the well will be 2.5m, so a 2.5m probe will be used. The probe will be hanging from the top of the well, with 2.5m of cable between the top of the probe and the hanging point.

Occasionally however, the probe will be installed to measure the full range of the well, such as when it is a back-up to an ultrasonic sensor. The top of the probe will be close to the mounting bracket, so an installer may think to pull the excess cable back through the conduit so that it is not hanging in the well, as shown in the first photo. The probe rarely needs cleaning, as the turbulence of the inflow cleans the debris off the probe (as seen in the first photo). However, if it does need cleaning, the method is to simply pull the probe up through the cleaning bracket, as shown in the second photo. This will require slack cable between the conduit entry and the top of the probe, equivalent to the length of the probe. The probe in the first photo cannot be cleaned in it’s current state. Cable will need to be pulled back through the conduit, and hung looped from the mounting bracket.

Probes are supplied with either 10m (30’) or 30m (100’) of cable as standard, longer lengths are available on request (but will incur shipping delays). If in doubt, it is better to have 19m too much cable than to have 1m not enough!

Probe installed without sufficient cable to facilitate lifting out of wetwell for cleaning.

Probe being cleaned.

In the well probe, probe installation