Slant/Fin Nuisance Low Water Cutoff Trips

Boiler frequently locks out on low water, even though system appears full

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Improper LWCO installation height, Fouled LWCO probe, Electrical noise on LWCO circuit, Air pockets near LWCO on Slant/Fin boiler

Safety: Turn off power before servicing LWCO. Do not bypass low water safety.

Steps:

1. Check system pressure: Confirm pressure is adequate for the building height.
2. Bleed near LWCO: Remove air from piping near the LWCO tapping to ensure the probe is submerged.
3. Clean probe (if removable): A technician can remove and clean the LWCO probe to restore proper operation.

Professional help: Persistent nuisance trips require a technician to evaluate LWCO location and wiring.

Medium 3/5

Low Water Cutoff

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