Hydrolevel 550SV Low Water Cut-Off

The Hydrolevel 550SV Low Water Cut-Off is a specialized safety control engineered for hot water boiler applications where a manual reset is required. This 120VAC unit (Part No. 45-551) utilizes a Safgard EL1214-SV sensing probe to monitor water levels via hydrostatic pressure and conductivity, providing 15,000-ohm sensitivity. Designed for direct-mount installation via a 3/4" NPT connection, the 550SV prevents dry-fire conditions by interrupting the burner circuit if a low water state occurs. The integrated 30-second delay helps prevent nuisance shutdowns during surges, while the LED indicator light and test button allow technicians to verify operation and diagnose system status quickly. Rated for up to 160 psi and 250°F, this NEMA 1 enclosure control is the industry standard for light commercial and residential hydronic heating systems that must meet stringent ASME safety codes.

Key Technical Benefits

• Enhanced System Safety: The manual reset LWCO configuration ensures the burner remains locked out until a technician can inspect the system and resolve the underlying water loss issue.
• Reliable Probe Sensing: Use of the EL1214-SV probe eliminates mechanical floats that can scale or seize, ensuring high-accuracy detection even in harsh water conditions.
• Streamlined Installation: Designed for direct installation into boiler tappings, reducing the need for complex external piping or bypass loops.
• Diagnostic Capability: The built-in test button allows for functional verification without draining the system, saving time during annual maintenance cycles.

Common Technical Questions

Is the Hydrolevel 550SV compatible with steam boilers?
No, this specific model is designed exclusively for hot water boilers. Steam applications require the 400 series or similar models designed for steam environments.

What is the purpose of the 30-second delay?
The 30-second delay on the manual reset prevents "bounce" or nuisance tripping caused by momentary water level fluctuations during pump startup or thermal expansion.

Can this unit be mounted in any orientation?
The probe must be installed in a horizontal tapping above the boiler tubes to ensure it accurately detects low water conditions before damage occurs to the heat exchanger.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.