Hydrolevel 500SV Low Water Cut-Off

The Hydrolevel 500SV Low Water Cut-Off is a 24Vac safety control specifically engineered for commercial hot water boilers and secondary protection on steam systems. Built for rigorous field environments, the 45-501 model features a manual reset configuration that requires operator intervention if a low water condition persists for more than 30 seconds. This ensures that a technician inspects the system before resuming burner operation, providing a critical layer of dry-fire prevention. The unit includes the EL1214-SV sensing probe, which is specifically designed with a shorter length to facilitate installation in standard black iron tees or high-clearance fittings without obstructing flow or sacrificing signal integrity.

Equipped with intensive diagnostic tools, the Safgard 500SV features an integrated test button and LED status light, allowing contractors to verify the burner circuit and control logic without manually draining the system. The solid-state design eliminates the mechanical failures common in float-style switches, utilizing the water’s conductivity to complete the circuit between the probe and the boiler shell. This 24V low water cut-off meets ASME CSD-1 requirements for commercial installations and is designed to remain locked out during power interruptions, preventing accidental resets that could damage a depleted boiler. Its compact 3/4 inch NPT connection and robust ceramic insulation on the probe make it a standard choice for tech-heavy hydronic maintenance.

• Manual Reset Safety: Prevents automatic burner restart after a 30-second low water lockout, ensuring professional inspection.
• EL1214-SV Shorter Probe: Specifically designed for mounting in standard black tees and tight manifolds where internal clearance is limited.
• No Moving Parts: The electronic probe technology avoids the clogging and sticking issues typical of traditional float-style controls.
• Diagnostic LED and Test Button: Facilitates rapid troubleshooting and burner circuit verification without compromising system water levels.
• ASME CSD-1 Compliant: Engineered to meet stringent commercial safety standards for water boiler secondary protection.

Can this be used on a steam boiler?
The 500SV can be utilized as a secondary low water cut-off on steam boilers, but it must not be used as the primary safety control for steam applications.

What is the purpose of the 30-second delay?
The delay prevents nuisance shutdowns caused by temporary water surges or turbulence, only locking out the burner if the probe remains dry for the full duration.

Does this unit reset after a power outage?
No, if the unit was in a lockout state due to low water, it will remain in manual lockout after power is restored to prevent dry firing while unattended.

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.