Weil-McLain UO-3 123k 87% Hot Water Oil Boiler

Model: 386901006 Item Number: 81666
Weil-McLain 386901006
Weil-McLain 386901006
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Weil-McLain UO-3 123k 87% Hot Water Oil Boiler
Weil-McLain UO-3 123k 87% Hot Water Oil Boiler Model: 386901006 Item Number: 81666
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
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*This product qualifies for Free Lift Gate Service. Items over 100lbs normally ship via semi-truck. Select this service if you need the product lowered to the ground curbside. To learn more about Lift Gate Service, read our shipping policy.
Specification Highlights
    New Learn More
    This product is new and has never been used. It's in its original packaging, which has not been opened.
    636 Pounds Learn More
    636 Pounds
    Total weight of the product and any included accessory/components. This total is not the shipping weight, as it does not include packing material, which may increase the overall shipping weight of this product.
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Recommended Accessories
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Required Accessories Add All Required
Installation Accessories
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Overview for Weil-McLain 386901006

Over the last 130 years, Weil-McLain has built a reputation of designing some of the most reliable boilers in the marketplace. Weil-McLain's Ultra hot water boiler is highly efficient, simple to install, and remarkably durable. Using condensing technology, the Ultra will reuse heat that escapes from conventional boilers, providing greater efficiency. When equipped with the optional Weil-McLain Advanced Features Module (AFM), the Ultra is a very user-friendly boiler. A clear display screen relays information about operations, temperatures, and system status. With AFM and an 87% AFUE, the Ultra UO-3 makes comfort and efficiency more accessible than ever before.
  • 3-Pass Heat Exchanger
  • The UO-3 uses a 3-pass cast iron heat exchanger. This design is more efficient and provides better flame control than non-3-pass designs, reducing your heating costs.
  • Venting Flexibility
  • UO-3 boilers can be placed into an existing chimney vent or direct vented. By using the direct vent exhaust gasses are simply piped out your home, no power-assisted fan needed.
  • Simple to Service
  • Another benefit of the 3-pass design is the horizontal configuration. With the swing-away door open, the UO-3 combustion area and flue are exposed for easy cleaning or maintenance.
  • Captured Seals
  • Silicone-coated fiber ropes are used for sealing the boiler sections. These seals expand and contract with the boiler, keeping the unit watertight and preventing contaminants from entering your system.
  • Burner Options
  • Beckett NX, Beckett AFG, Carlin, Riello
  • Product Note
    This boiler does not include an oil burner. Please see the Accessories tab for compatible burners if you require one.
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    Product Category
    General Information
    Product Line
    Product Category
    Medium Learn More
    Medium refers to the substance that carries heat through the heating system. Systems are either designed to use either Hot Water or Steam as a medium, and components are usually specific to one or the other.
    Hot Water
    Fuel Type Learn More
    Fuel Type
    To create heat, some form of fuel is required. Fuel Type specifies what the product uses as an input to create heat.
    Combustion Type Learn More
    Combustion Type
    Condensing appliances use leftover thermal energy from combustion gases to heat water in a secondary heat exchanger, resulting in higher efficiency and lower exhaust temperature.
    Vent Type Learn More
    Vent Type
    Products that use combustion (burning) of fuel to create heat also create potentially dangerous gasses that need to be exhausted (AKA "Vented"). Depending on the product, venting can be done via a chimney, through a side wall, or use a second vent to provide fresh air to the appliance.
    Chimney Vent
    DHW Production Learn More
    DHW Production
    DHW (Domestic Hot Water) is potable water for uses other than space heat. Some boilers are able to provide DHW "out of the box", while others can do so with the purchase of optional accessories.
    Modulating/Staging Learn More
    Stages are unique speeds or levels that equipment can operate at. More stages allow for better fine-tuned control of output, which improves comfort and efficiency. Modulating equipment can operate across a range of levels, giving the highest level of fine-tuned control.
    Mount Type
    Maximum Altitude
    5500 Feet
    Assembly Type
    Includes Pump
    Burner Model
    Sold Separately
    AFUE Learn More
    AFUE (Annual Fuel Utilization Efficiency) measures the efficiency of combustion equipment over the entire heating season, and is calculated by dividing the amount of energy that is actually heating your home by the total energy contained in the fuel used by the boiler/furnace.
    87 %
    Input Rate
    1 GPH
    DOE Heating Capacity Learn More
    DOE Heating Capacity
    Also referred to as Gross Output, this is the output of a boiler after accounting for combustion efficiency. We recommend sizing hot water boilers based on the DOE Heating Capacity.
    123000 BTU
    Net I=B=R Capacity Learn More
    Net I=B=R Capacity
    I=B=R, also referred to as Net Output or AHRI Capacity, is the rated heat output of a boiler after accounting for combustion efficiency, piping loss, and an extra pickup factor. We recommend sizing steam boilers based on the I=B=R rating.
    107000 BTU
    Electrical Data
    60 Hz
    Flue Connection Size
    6 Inches
    Supply Connection
    1 1/2 Inches
    Return Connection
    1 1/2 Inches
    Product Height
    40 Inches
    Product Width
    22 1/16 Inches
    Product Depth
    25 Inches
    Product Weight
    636 Pounds
    Shipping Weight
    636 Pounds
    Country of Origin
    United States
    Energy Star Listed
    CSA Listed
    AHRI Certified
    AHRI Reference Number
    Warranty Information
    Parts Warranty Show ACW Parts Warranty Learn More
    Parts Warranty
    A warranty is a safeguard from defects in manufacturing and can vary in length and terms. Some manufacturers require registration for extended warranty benefits, be sure to check out features and the warranty document. To see the manufacturer's warranty statement, click on the Manuals tab. Learn More
    1 Year
    Heat Exchanger Warranty
    20 Years
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    Weil-McLain UO-3 123k 87% Hot Water Oil Boiler
    Weil-McLain 386901006
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