The AO‑3E is a compact, high‑efficiency three‑section cast‑iron oil boiler designed for reliable hydronic heating in residential applications. Equipped with an ECM circulator and a factory‑installed burner, it delivers strong performance with reduced electrical consumption and smooth, quiet operation. This model is built for chimney venting and comes less tankless coil, making it ideal for homes using an indirect water heater or dedicated hot‑water system.
Key Features
Three‑section cast‑iron heat exchanger engineered for even heat transfer, long service life, and stable operating temperatures.
ECM circulator that lowers electrical usage while improving system efficiency and comfort.
Factory‑installed oil burner (Beckett, Carlin, or Riello depending on configuration) tuned for clean, consistent combustion.
Chimney‑vented design for straightforward replacement of older atmospheric oil boilers.
Less tankless coil configuration, ideal for pairing with an indirect water heater for higher domestic hot‑water output and efficiency.
Quiet, low‑vibration operation supported by the Advantage series’ combustion and airflow design.
Service‑friendly layout with accessible components and clean wiring for easier annual maintenance.
Ideal Applications
