Sensor WLD Relay 1W-UNI: Water Leak Detector

A universal WLD (Water Leak Detection) sensor, with one WLD sensing cable input and 2 kinds of outputs.

  • Relay Output: Sensor WLD Relay requires an external 12V power supply, OK / Water / Disconnected states of WLD detection input are signaled by relay output (NO/NC).
  • 1W-UNI (RJ11) Output: Sensor WLD Relay is connected by RJ11 cable to any HWg device (STE2, Poseidon, Ares, ...) as a standard external sensor. 

Sensor WLD Relay is input for one WLD zone. Several sensors can be used with one Poseidon / Ares device for WLD detection in several zones.

The sensor detects water occurrence by soak-detecting cable. Soaking or interrupting of cable cause the switching of relay contact.

  • External WLD sensor for al RJ11 (1W-UNI) devices (Poseidon2, Ares, STE2, ...)
  • Sensor WLD Relay 1W-UNI is powered from RJ11
  • WLD input is 1 water detection zone up to 185 meters
  • Even the smallest volume of water, ethylene glycol, or other conductive liquid is detected anywhere along the entire length of the sensing cable
  • WLD by HWg is unique long-term stable technology because of none Bend / Twist / Grip limits
Applications and usage: 
  • Water leak detector for security systems
  • Water detection under raised floors
  • Leaky pipe detection (cable wrapped along the pipe)
  • Protection against floods from roof lights (sensing cable routed along the walls)
  • Detection of water leaks in drip trays
  • Detection of water leaks under air-conditioning outlets


Horizontal menu

WLD relay installation

Sensor WLD Relay can be used as a Standalone WLD sensor (power + relay output) or as a 1W-UNI sensor connected to any STE2, Poseidon2, HWg-Ares, or other HWg devices.

WLD relay and sensing cable installation

WLD sensing cable

  • WLD sensing cable detects liquid along the entire length of the sensing cable
    • even the smallest volume of water, ethylene glycol, or other conductive liquid
    • re-usable (cable can be cleaned, dried & used again)
  • Zone detection states: OK / Flooded / WLD cable disconnected
  • The „WLD sensing cable A
    • supplied in length from 2m to 50m (up to 185 meters/zone in total)
    • can be extended by non-sensing WLD prolong cable A
    • terminator is required at the end of the zone (included in the default WLD sensing cable A - 2+2)

WLD relay with WLD sensing cable - use case


WLD sensing cable features

  • No Bend limit: WLD sensing cable Type A is not limited by any bending radius. The sensing cable can be knotted and still works properly.
  • No Twist limit: WLD sensing cable Type A can be twisted as any other electrical cable. 
  • No Grip limit: Water detection functionality is not limited by point pressure within a reasonable range.

WLD cable qualities

WLD sensing cable components

  • Connection cable - 2m (Green terminal block, 2m,  Terminator)
  • WLD Sensing cable A - 2m / 10m / 50m
  • WLD prolong cable A - 5m

WLD cable components

WLD sensing cable vs. Flood detectors

Flood detection requires the installation of a detector in a place where water will likely be located after leakages from various sources of flooding (cracked water pipes, glycol from the cooling system, wastewater). The Flood detector has to get entirely flooded to trigger an alarm. WLD sensing cable detects liquid along the entire length of the sensing cable and even the smallest amount of liquid can send the alert.

HW group offers several products that provide ideal solutions for flood and water leak detection. See the table below and discover the best solution for your situation:

Water Leak Detection (WLD) devices and detectors
  WLD2 SD-WLD NB-WLD WLD-Relay Flood detector
Flood detector

Water: Spot detection

- - - - yes yes

Water: WLD (Sensing cable)

yes yes yes yes - -

Detection zones / Spots

zones zone zone zone spot spot

Max length of WLD cable

185 m 185 m 60 m 185 m - -
 Connectivity / Interface


- - yes - - -

LAN (RJ45)

yes yes - - - -


yes yes - - - -

1Wire-UNI (RJ11)

- - - yes yes -

Relay output (NO/NC)

- - - yes - yes


WLD system - Alerting
  WLD2 SD-WLD NB-WLD WLD-Relay Flood detector
Flood detector

SensDesk Portal Connectivity

Yes Yes (mandatory) Yes (mandatory) Via external device Via external device Via external device

Web interface, SMTP

Yes Via portal Via portal - - -
Output states 0 (ok), 1 (water),
2 (cable failure)
0 (ok), 1 (water),
2 (cable failure)
0 (ok), 1 (water),
2 (cable failure)
(ok), (water),
2 (cable failure - RJ11 output)
0 / 1 0 / 1

Disconnected device alert

Via portal Via portal Via portal Yes (sensor = -999) - -
Remote relay alert Yes Via portal Via portal Via external device Via external device Via external device


WLD/Flood detectors: WLD Relay / Flood detector 1-W UNI / Flood detector LD-12

Sensor WLD relay 1W-UNI   Flood detector 1W-UNI   Flood detector LD-12 product photo


WLD devices: WLD2 / SD-WLD / NB-WLD

WLD2 product photo SD-WLD product photo NB-WLD product photo


WLD device comparator


Recommended products

WLD connection cable A

Connection cable for connecting WLD device with WLD sensing cable.

WLD prolong cable A

Prolong non-sensitive cable 5m for WLD type A. Can be extended to up to 100m in total.

WLD sensing cable A

2m of WLD sensing cable type A. Water is detected along the entire length of the WLD sensing cable.

Poseidon2 4002

Secure solution for remote environment monitoring and control of outputs.

Ares 12 LTE

Industrial measuring and monitoring for 14 sensors with GSM and LTE communication and back-up power.


Remote monitoring device with internal battery, connected to NB-IoT cellular network with external sensors (temperature, humidity, Voltage, ..).