A high‑capacity four‑section cast‑iron oil‑fired water boiler engineered for reliable hydronic heat and on‑demand domestic hot water. Built on the proven Gold S4 platform, this packaged model includes a factory‑installed oil burner and an integrated tankless coil, providing continuous hot‑water production without the need for an indirect tank. The 386701029 is configured for natural‑draft chimney venting, making it a straightforward replacement for older atmospheric oil boilers.
Key Features
Four‑section cast‑iron heat exchanger designed for strong heat output, even heat transfer, and long‑term durability.
168,000 BTU heating capacity suitable for larger homes or higher‑demand hydronic systems.
Integrated tankless coil delivering on‑demand domestic hot water directly from the boiler.
Factory‑installed oil burner matched to the boiler’s firing rate for clean, stable combustion.
86% AFUE efficiency providing dependable performance with simple annual maintenance.
Natural‑draft chimney venting ideal for retrofit installations using existing flue systems.
Service‑friendly layout with accessible burner, controls, and piping connections.
Quiet operation supported by Weil‑McLain’s combustion chamber and cast‑iron block design.
Ideal Applications
Homes needing a high‑capacity oil boiler that provides both hydronic heat and domestic hot water via a tankless coil, especially where chimney venting is already in place.
