The Fulton Low Water Cut-Off (LWCO) relay is one of the most critical safety components on a Fulton vertical tubeless steam boiler. When the boiler water level drops below a safe minimum — detected by the low water probe — the LWCO relay cuts off the burner to prevent dry-firing and boiler damage. These are the most frequently replaced Fulton boiler parts.
⚠ Always confirm part number with your boiler model. The 2-40-001421 replaced the 2-40-000421 in current production — check your boiler's control panel and wiring diagram before ordering. Call (901) 458-2000 for confirmation.
LWCO Safety Relay
Low Water Cut-Off
ICS · ICX · VMP Series
Most Commonly Replaced