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The Level Probe Relay (LPR-1) senses liquid level and provides a relay output for controlling a pump or level alarm. The unit is a, DPDT, 12 pin plug-in, has two inputs, an ON and an OFF, for connection to two electrodes of a conductance probe. All setup is easily done using the DIP switches on the unit.

When used for a level alarm the ON and OFF inputs may be connected to the same electrode on the probe, or the ON input may be used by itself. When used for pump control the ON and OFF inputs are typically connected to two different level probe electrodes to provide a latching function.
Unit of Measure


UL File No.

N/A #E101681

Supply Voltage (AC)

N/A 120 V

Supply Voltage Tolerance

N/A ± 10%

Supply Phase

N/A Single Phase

Supply Frequency

N/A 50/60 Hz

Max. Power Consumption

N/A 3.8 V·A

Relay Type


Sensor Output Voltage

N/A ± 12 V Square Wave

Sensor Output Current

N/A ± 1.2 mA max (per sensor)

Operating Temperature

N/A -40 to 60 ºC

Storage Temperature

N/A -45 to +85 ºC

Enclosure Material

N/A Poly Carbonate

Base Material

N/A Phenolic

Plug-In Socket


Additional Description

Additional Description

N/A The Conductance Relay has two pump control modes, Pump Down (empty a tank) and Pump Up (fill a tank). When in the Pump Down mode and both inputs detect liquid, the unit energizes the relay and keeps it energized until the level drops to the point where the OFF input no longer detects liquid. When in the Pump Up mode and both inputs detect no liquid, the unit energizes the relay and keeps it energized until the level rises to where the OFF input detects liquid.

The Sensitivity of the unit must be set for the type of liquid being detected (see the Dip Switch table). The unit provides a 10 second power up delay to prevent a pump from being turned on too soon after a power interruption. An adjustable ON Delay is provided for use as a lag pump delay. The adjustable OFF Delay is provided so that the unit may be used to provide timed off, backup pump control. (See the Dip Switch table for ON and OFF delay settings.)