WTGO-6R - 149,000 BTU Output Cast Iron Gold Oil Boiler w/ Tankless Heater - Series 4 (Burner not included)

Weil-McLain WTGO-6R Oil-Fired Water Boiler – Integrated Tankless Option with Proven Cast Iron Reliability

The WTGO-6R from Weil-McLain is an oil-fired, cast iron hot water boiler designed for residential and light commercial systems. This model includes an internal tankless water heater, making it suitable for combined space and domestic hot water applications without the need for an indirect tank.

With a heating capacity of 149,000 BTU/hr and a net I=B=R rating of 129,000 BTU/hr, the WTGO-6R supports high-demand systems while maintaining thermal consistency. The boiler features Weil-McLain’s cast iron heat exchanger design, known for long service life, thermal mass retention, and straightforward serviceability in field conditions.

Core System Features

• Cast Iron Sections: Heavy-duty heat exchanger designed for longevity and consistent performance under variable load conditions.
• Tankless Coil Integration: Built-in high-capacity tankless heater delivers domestic hot water on demand.
• Flue Options: Rear or top flue outlet (7" diameter) allows flexible venting in retrofit or new construction applications.
• Access for Service: Hinged burner swing door and quick-open top provide full combustion chamber accessibility for cleaning and inspection.
• Preassembled Trim: Shipped with factory-installed circulator, service switch, and terminal strip wiring to streamline field setup.

Performance Specifications

• DOE Heating Capacity: 149,000 BTU/hr
• Net I=B=R Rating (Water): 129,000 BTU/hr
• Maximum Working Pressure: 50 PSI
• Flue Outlet: 7" (rear or top)
• Tankless Coil Capacity: High recovery rate – check current model datasheet for flow specifics
• Combustion Type: Oil-fired, atmospheric
• Material: Cast iron block, aluminized steel flue collector
• Burner Compatibility: Beckett, Carlin, or Riello (field-installed)

Installation and Application Notes

The WTGO-6R is designed for closed-loop hot water heating systems and includes a tankless coil for DHW supply. Installation must comply with local fuel oil, electrical, and venting codes. A barometric damper is required for proper draft control. This model is not configured for steam and should not be used in open heating systems. Burner and controls must be selected per jobsite conditions and fuel type.

Common Applications

• Single-family homes with domestic hot water and space heating from a single appliance
• Retrofit projects replacing older oil systems with integrated coil boilers
• Homes requiring top or rear flue venting due to mechanical room layout constraints

Warranty Coverage

• Heat Exchanger: 20-year limited warranty
• Parts: 2-year limited warranty