Warrick Troubleshooting Guide

ELECTRONICS Series 16, 26, DF, 17, 27,37

1. Failure of relay to change state when liquid touches probes. (Condition shows electrodes are dry)

  • Check connection of electrodes – are there any shorts?
  • Check wiring between probes and relay for correctness and continuity.
  • Check electrodes to make sure they are clean.
  • Check to be sure liquid is actually touching the electrodes.
  • Does the supply voltage match that of the control?
  • Do you have the correct sensitivity for the liquid you are using? The relay may not be sensitive enough for the media.
  • Is the media conductive? Hydrocarbons (Oil, gasoline, solvents) are not conductive.
  • What is the load you are switching? If the load exceeds what the control is listed for, the contacts may have fused.
  • Check to see if the distance between the tank and where the control is mounted exceeds the distance parameters (see chart p. E2)
  • Make sure the high electrode is not further than 4 feet from the ground reference electrode. If the customer has an application like this, they can drop a second reference electrode next to the high probe. Simply connect another reference probe to the ground reference. This also applies if customer is using the control as a single point level service (only using the H and G probes) if the ground reference is greater than 4 feet, the signal may be lost.

2. Control triggers falsely (Condition shows electrodes are wet)

  • Check to make sure the ground reference is not shorting to the sensing electrodes. This shorting can happen:
      A. In foaming applications – foam acts as media and it bridges from one probe to the other. – solution: add heat shrink to the electrodes.
      B. Water in the conduit.
      C. One probe touching the other.
  • Do you have the correct sensitivity for the liquid you are using? The relay may be too sensitive for the media.
  • What is the load you are switching? If the load exceeds what the control is listed for, the contacts may have fused.
  • Check wiring between probes and relay for correctness and continuity.
  • Check for intermittent shorts caused by buildup over insulator on underside of probe housing.

3. Control triggers intermittently or sporadically on its own

  • Do the control wires that connect to the electrodes or level switch share conduit with high power wires? IE. >120 volts? If it does, this can create EMF (Electromagnetic Field). If this is created, the control may be susceptible to false tripping. Solution: Run the control wiring with shielded cable. Better yet, run in a dedicated metal conduit.
  • Is any of the control wiring running close to anything that has EMF potential? If yes, move it.
  • Is the control mounted in a panel, which is using a VFD (Variable frequency drive)? VFDs are pump controls, which can create a lot of EMF. If VFDs are used, move the control away from it.
  • Is there sloshing in the tank? Like a float, the liquid may slosh on and off the probe, causing it to trip on and off.

TESTING PROCEDURES FOR ALL ELECTRONICS

It is important to isolate the control from the fitting and electrodes. By isolation you can determine if the problem is with the control, or if it is with the sensor. To do this, disconnect the wires that run to the fitting and the electrodes. Disconnect the wires from the contacts that run to the load – this is the Common, N.C., and the N.O.

Now you are ready to test the control. Keep in mind what type of control you have, what the mode of operation is, and if it is differential level service or single point level service. Be sure to check if the controls have time delays and be sure customer waits long enough for the control to change state.

The following test simulates the media covering and uncovering the electrodes by jumping the corresponding terminals. When talking to the customer, it is helpful to have the IO bulletin in front of you to correspond to the proper terminal numbers.

Single Point Direct Mode Control / Series 26 / or LWCO side of DF Control –Uses G and H electrodes

  1. With a jumper wire, jump from terminal G to Terminal H – the control should energize.
  2. Remove the jumper. The control should de-energize.

Differential Level Direct Mode Control – Uses G H and L electrodes (Usually used in pump down applications)

  1. With a jumper wire, jump from terminal G to Terminal L. Nothing should happen. This prepares the control to latch.
  2. Keeping the first jumper from G to L, place another jumper wire from terminal L to terminal H. The control should now energize.
  3. Remove the jumper from terminal H to L. The control should remain energized.
  4. Remove the jumper from terminal L to G. The control should now de-energize.

Single Point Inverse Mode Control - Uses G and H electrodes

  1. As soon as this control has power connected to L1 and L2, the control should energize. With a jumper wire, jump from terminal G to Terminal H – the control should de-energize.
  2. Remove the jumper. The control should energize.

Differential Level Inverse Mode Control – Uses G H and L electrodes (Usually used in fill applications)

  1. As soon as this control has power connected to L 1 and L2, the control will energize. With a jumper wire, jump from terminal G to Terminal L. Nothing should happen. This prepares the control to latch.
  2. Keeping the first jumper from G to L, place another jumper wire from terminal L to terminal H. The control should de-energize.
  3. Remove the jumper from terminal H to L. The control should remain de-energized.
  4. Remove the jumper from terminal L to G. The control should now energize.