Wireless Tank Level Switch for Solar Water Pumps | Grundfos SQFlex Compatible

The Back 40 Solar B40-WTS is a solar-powered wireless tank level switch that automatically stops your pump when a storage tank reaches full, eliminating costly overflows and manual monitoring on remote water systems.

Key Features:

• Long-Range Wireless Communication: Tested signal range of 2.5 miles with potential reach of 5+ miles, traveling through trees and terrain obstacles with magnetic-base antennas for flexible mounting.
• Solar or AC Powered: Transmitter and receiver each run on dedicated solar panels included in the kit, with optional AC operation available for grid-connected pump systems.
• Compatible with Stainless Probes or Float Switches: Works with both stainless steel moisture sensing probes and mechanical float switches, supporting normally open signal inputs across a wide range of sensor types.
• Broad Controller Compatibility: Connects directly to Back 40 Solar pump controllers (PSC100, CU200, PSC200), Grundfos CU301, and generic VFDs or third-party controllers via operating-open terminal inputs.
• Complete Kit — Ready to Install: Includes transmitter, receiver, two solar panels, tank full sensor or float, sensor splice kit, and mounting hardware — everything needed for a full installation.

The B40-WTS transmitter mounts at the storage tank and connects to your tank full sensor or float, while the receiver mounts at the pump controller and signals it to shut off when the tank is full. Periodic transmission checks occur every 10 seconds, providing reliable automated pump cutoff without continuous radio traffic.

The controllers ship pre-mounted to the solar panels for faster setup, with screws and mounting feet included for separate shade-mounted installation.

Antennas feature a magnetic base for attachment to any ferrous metal surface and can also be adhesive-mounted on non-magnetic structures. For best range, antennas should be mounted vertically at an elevated location with clear line of sight between the transmitter and receiver.

AC systems support both 120VAC and 240VAC via separate contactors, with a maximum current rating of 30A FLA — suitable for a wide range of submersible and surface pump applications.

Status indicator lights on both controllers confirm power, communication, and tank-full state at a glance. The sealed enclosures with locking wire glands protect electronics from moisture, debris, and insects in outdoor farm, ranch, and homestead environments.

Technical Specifications