Overview
The ABB LLC54AA is a robust dual-probe conductive liquid level control relay engineered for industrial pump and tank applications. Rated for 120V AC, 5 AMP, SPDT, 8 Pin Plug-In Type, this controller delivers reliable level sensing and switching for fill or drain operations. It provides dual-probe conductive liquid level control with adjustable sensing resistance to 100 kΩ, making it adaptable to different tank geometries and liquid conductivity profiles.
Key Features
- Dual-probe conductive liquid level control in a convenient octal plug-in package
- Isolated, pulsed DC voltage on the probes prevents electrolytic plating
- Less than 1mA of current is used to sense the presence of conductive liquid between the probes and the common
- Models are available for fixed fill or drain operation
- SPDT single-pole double-throw switching enables both pump start and pump stop logic
Technical Specifications
- Input Voltage: 120V AC
- Switching Contacts: SPDT (Single Pole Double Throw)
- Contact Rating: 5 Amperes resistive at 240VAC
- Package Type: 8-pin plug-in socket
- Sensing Method: Dual-probe conductive
- Adjustable Resistance: Up to 100 kΩ
- Probe Current: Less than 1 mA
Typical Applications
The LLC54AA is well-suited for:
- Sump pump and effluent pump control systems
- Tank fill/drain automation in chemical processing
- Water treatment and wastewater applications
- HVAC condensate drain management
- Irrigation and agricultural liquid management
- Industrial reservoir level monitoring
Compatibility & Replacements
The ABB LLC54AA is manufactured by SSAC (now part of Littelfuse) and remains a recognized standard in the LLC5 series of liquid level controls. For applications requiring dual-probe sensing with 120VAC operation and 5-amp switching, this relay is a direct fit-and-mount solution. Parts engineers should verify probe configuration (fill vs. drain) and adjustable resistance settings against specific tank and load requirements before installation. This used unit offers cost-effective inventory replenishment for maintenance teams and integrators managing legacy control systems.
