Series 26M Bench Test
The below instructions help describe how to bench test a Series 26M conductivity relay. 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.
Single Level Direct Mode
The Series 26M conductivity relay is only available in direct mode for single level service. This relay is mostly used as a boiler low water cutoff. Therefore, the Normally Open (NO) contact typically controls the boilers burners, and so when the liquid level drops beneath the Low-Level Cutoff (LLCO) probe, the NO contact will open and take power away from the burner as a safety interlock.
The below diagram explains how to test the board if using it as a low-level cutoff. Place a jumper between LLCO and G (Reference) contacts. This will simulate that the LLCO and G probes are in the liquid and the relay will energize (LED on). The Series 26M relay has powered contacts so when the relay is energized there will be voltage out on the Normally Open (NO) contact. The voltage will match the relay’s supply voltage, 120, 240, 24, or 208/240VAC.
Next step is to remove the jumper between LLCO and G. This will simulate that the probes (LLCO and G) are not in the liquid. The relay will deenergize, and you should have no voltage out on the Normally Open contact, and voltage now on the Normally Closed contact.
Manual or Automatic Reset
Series 26M relay can be configured as a manual reset or automatic reset. In manual reset, when the liquid falls below the LLCO probe, and then rises so that the LLCO is back in the water, the manual reset (Normally Closed pushbutton) will need to be depressed before the relay will energize.
In automatic reset, when the liquid falls below the LLCO probe the relay will deenergize. When the liquid level rises back so that the LLCO probe is back in the water, the relay will energize automatically, without the need to depress a pushbutton.
In automatic reset mode the reset terminals are left empty. Do not place a jumper between the reset terminal in lieu of a NC pushbutton. This may cause the relay to enter a fault condition.
For additional technical help please review the Series 26 Fault Code Troubleshooting page and the Warrick Relay Troubleshooting Guide.