Bolec Solar Pump Dry Run Protection System – Works in Dirty Water (WL701)

Bolec WL701 Solar & Irrigation Pump Dry Run Protection Kit with Probe

Protect solar and irrigation pumps from dry running and low water conditions before damage occurs.

The Bolec WL701 is a 12/24V low water level alarm and pump protection kit designed for
solar pumping systems, irrigation pumps, diesel-driven pumps, and remote water transfer applications.
When water drops below the probe, the WL701 activates an alarm and can also switch an external relay,
warning light, or shutdown circuit.

Unlike optical sensors that can become unreliable in dirty or sediment-heavy water, the WL701 uses a
conductive AC-sensing probe. This makes it a practical solution for real-world pumping applications
where water quality is not always clean or consistent.

Field feedback from a solar pumping installation in rural NSW reported that the WL701 provided a reliable
replacement for an optical water sensor that had ongoing issues in water with high sediment and mineral levels.
The same feedback also noted that the system worked well on the suction side of the pump, with the built-in
delay helping to ignore bubbles in the suction line. :contentReference[oaicite:3]{index=3}

This kit is ideal for applications where you want to:

• stop a pump from running dry
• detect low water level before pump damage occurs
• replace unreliable optical sensing in dirty water conditions
• add a warning light, buzzer, or shutdown signal to a pump controller

Kit includes:

• WL701 low water level alarm module with built-in buzzer and output relay
• WL601P probe with connector and brass boss
• 8-pin wiring harness
• LED for external visual indication

Why Use the WL701 for Pump Protection?

• Designed for 12V and 24V DC systems commonly used in solar and remote pumping setups.
• Helps prevent pump damage caused by low water level or dry run conditions.
• Works with external alarms, lights, relays, and shutdown circuits for flexible installation.
• AC probe sensing helps reduce plating and scale build-up on the probe. :contentReference[oaicite:4]{index=4} :contentReference[oaicite:5]{index=5}
• Suitable for dirty water applications where optical sensors may be unreliable, based on field feedback from an actual solar pump installation. :contentReference[oaicite:6]{index=6}
• Built-in delay helps prevent nuisance alarms from turbulence, movement, or bubbles in the line. The documentation specifies an approximately 7 second delay. :contentReference[oaicite:7]{index=7}
• Fail-safe behaviour helps detect broken sensor leads and alarm circuit faults. :contentReference[oaicite:8]{index=8} :contentReference[oaicite:9]{index=9}

Real-World Application

A maintenance fitter on a cattle property in NSW installed the WL701 to protect a
Mono solar pumping system after the original optical sensor caused repeated problems.
According to the feedback, the optical sensor either stopped the pump unnecessarily or allowed it to run dry.
After installing the WL701, it was found to be a very reliable method of protecting the pump,
including in water with high sediment or mineral content. :contentReference[oaicite:10]{index=10}

The same installation used a stainless steel fitting on the suction side of the pump so that water
could be sensed at the inlet. The user also reported that the 7 second delay compensated for bubbles in the suction line. :contentReference[oaicite:11]{index=11}

Best For

• solar pumping systems
• irrigation pumps
• diesel-driven transfer pumps
• remote water supply systems
• pump inlet low water detection
• dirty water or sediment-affected installations

Probe Benefits

The included WL601P probe is a conductive sensor designed to work with the WL701 module.
Because the sensing signal is AC rather than DC, it helps reduce electrolysis, plating, and deposit build-up
on the probe over time. :contentReference[oaicite:12]{index=12} :contentReference[oaicite:13]{index=13}

This is especially valuable in pumping applications where the water may contain sediment, minerals,
or contaminants that can affect other sensor types.

Wiring Diagram

Specifications

• Dimensions: Approximately 78 x 102 x 29mm overall. :contentReference[oaicite:14]{index=14}
• Voltage: 12/24 Volt DC Negative Ground systems. :contentReference[oaicite:15]{index=15}
• Probe sensing: AC signal only. No plating occurs. :contentReference[oaicite:16]{index=16}
• Contact rating: 12/24VDC 1.5A resistive. :contentReference[oaicite:17]{index=17}
• Time delay: Approx. 7 seconds after water falls below probe. :contentReference[oaicite:18]{index=18}

FAQ