Littelfuse Single-Probe Liquid Level Control

The Littelfuse Single-Probe Liquid Level Control line gives reliable conductive liquid level sensing for pumps, tanks, boilers and commercial equipment. Each control uses one probe and resistance sensing to detect whether conductive liquid is present. Depending on the model, it can be used for low-level cutoff protection or for fill (pump-up) and drain (pump-down) operation. These units are also called liquid level controllers, liquid level relays or probe-type level switches.

Key Features:

• Single-probe conductive sensing: a very low trickle current (under 1 mA) between the probe and common detects whether liquid is present.
• Built-in time delay: prevents rapid cycling of the output relay and the connected load.
• Isolated, low-voltage probe signal: an isolated AC sensing voltage at the probe helps prevent electrolysis.
• Relay output: an electromechanical relay switches the pump, valve or alarm circuit.
• Moisture and corrosion resistance: on the open-board models, the printed circuit board is conformal coated to resist moisture and corrosion.
• Multiple configurations: the line includes open-board and octal plug-in styles, in several input voltages and with fill, drain or cutoff operation. Some models have adjustable sensitivity to ignore foam and floating debris, and some offer manual or automatic reset.
• Approvals: many models are UL recognized and CSA certified, depending on the model.

Littelfuse is a well-known maker of circuit protection and protection relay products. Its liquid level controls are used in OEM equipment, HVAC and boiler systems, and commercial appliances. Choose the child item that matches your required voltage, operation mode, time delay and mounting style.