Series 19MR Inverse Mode Bench Test
The below instructions help describe how to bench test a Series 19MR conductivity relay in Inverse mode. This will help users ensure the relay is working properly and help explain the operation and wiring of the board.
The relay works off liquids natural conductive properties and is typically wired to conductivity probes. However, all Warrick conductivity relays also work with dry contact switches, like a LS-800 float level switch. This also allows users to place jumpers between the sensor contacts to help test the board.
Differential Level Service (Pump or Valve Control)
The Series 19MR can handle a direct motor load of 30 Amps at 240 VAC which eliminates the need for a contactor in between this relay and the pump. The load contacts are SPST so Inverse Mode can only be used for a Pump Up (Valve Fill) operation. If your application is for Pump Down (Valve Drain) then you will need to order this relay in the Direct mode, option ‘A’ or ‘B’. It cannot be wired backwards like other Warrick relays that have SPDT load contacts.
First step is to remove the probe/sensor wires from H, L, and G. This will simulate that all probes are dry and not in the liquid. Since this is an Inverse Mode relay, the relay will be energized, and the load contacts will close. The relay can be supplied with either 120 or 240 VAC, and your load contacts will match your supply voltage so measure to verify you have the correct voltage on the load side.
Next step is to place a jumper between L and G. This will simulate that the liquid level is rising, which is typical in a pump up (valve fill) situation. However, the relay should remain energized because it is latched, and still have voltage on the load contacts matching your supply voltage.
Last step is to add another jumper between H and G, and leave the jumper between L and G. This will simulate that the liquid level has risen and covered all the probes. The relay should now be deenergized (LED off) and the load contacts will be open with no voltage on them. There may be some leakage current left on the load contacts, so you may need to wire in your pump as the load, because your meter may read the full 120 or 240 VAC even though it will be in the milliamps.
Additional Tests to Run
After the relay is bench tested, you can also perform these same tests at the probe fitting. This will ensure the wiring is correct and there are no shorts present. You may need a helper to confirm the relay is actuating.
Since jumping the relay out does not test the relays ability to conduct through a liquid, you can also perform these same tests using a bucket of water. When it calls for two contacts to be jumped out, for example H and G, then both H and G probes should be placed in the bucket of water. This will accomplish the same thing and test the relays ability to conduct through the liquid.
You may also choose to leave the probes installed and place the probe wire directly into the bucket of water. In this case the wire will act as the probe and the probe wire.