A heavy‑duty five‑section cast‑iron oil‑fired water boiler engineered for high heating demand, long service life, and stable hydronic performance. Built on the proven Gold S4 platform, the 386701015 arrives as a factory‑packaged unit with burner installed, ensuring proper alignment, consistent ignition, and reduced installation time. With its 203,000 BTU output and natural‑draft chimney venting, it is an ideal replacement for larger atmospheric oil boilers in residential or light commercial applications.
Key Features
Five‑section cast‑iron heat exchanger delivering strong heat output, even heat transfer, and long‑term durability.
203,000 BTU heating capacity suited for larger homes or higher‑load hydronic systems.
Factory‑installed oil burner matched to the boiler’s firing rate for clean, stable combustion.
86% AFUE efficiency providing dependable performance with straightforward annual maintenance.
Natural‑draft chimney venting for easy retrofit into existing flue systems.
Quiet, low‑vibration operation supported by Weil‑McLain’s combustion chamber and block design.
Service‑friendly layout with accessible burner, controls, and piping connections.
Ideal Applications
Larger homes or light commercial buildings needing a high‑capacity, natural‑draft oil boiler with a factory‑matched burner and the proven reliability of the Gold S4 cast‑iron platform.
