A heavy‑duty six‑section cast‑iron steam boiler engineered for large residential steam systems requiring high output, dry‑steam performance, and long service life. Built on the proven Weil‑McLain Gold S4 platform, the 386701003 arrives as a packaged steam boiler with LWCO installed, but is supplied less burner, allowing installers to select the preferred burner brand or match an existing field‑installed burner. Designed for natural‑draft chimney venting, it is a strong replacement option for older atmospheric oil steam boilers in larger homes or multi‑radiator systems.
Key Features
Six‑section cast‑iron heat exchanger delivering high steam output, thermal stability, and long‑term durability.
245,000 BTU heating capacity suited for large homes or high‑demand steam systems.
Supplied less burner, allowing flexibility to install Beckett, Carlin, or Riello burners as required.
Integrated LWCO for safe operation and protection against low‑water conditions.
85% AFUE efficiency providing dependable performance with straightforward annual maintenance.
Natural‑draft chimney venting ideal for retrofit installations using existing flue systems.
Service‑friendly layout with accessible controls, steam trim, and piping connections.
Ideal Applications
Large homes or multi‑radiator steam systems needing a high‑capacity, natural‑draft oil steam boiler with built‑in LWCO and the flexibility to choose or reuse a burner.
