Cast Iron Natural Gas Boilers

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192 Products

Learn More About Weil-McLain 381359039
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 90k BTU Gross Input, 77k BTU DOE Capacity, 67k BTU Net IBR Capacity. Includes Circulator.
$3,164.04
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Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
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2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Weil-McLain 381359041
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 119k BTU Gross Input, 102k BTU DOE Capacity, 89k BTU Net IBR Capacity. Includes Circulator.
$3,556.00
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Weil-McLain 381359042
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 119k BTU Gross Input, 102k BTU DOE Capacity, 89k BTU Net IBR Capacity. Includes Circulator.
$3,534.31
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Weil-McLain 381359045
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 158k BTU Gross Input, 135k BTU DOE Capacity, 117k BTU Net IBR Capacity. Includes Circulator.
$4,008.53
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Weil-McLain 381359050
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 190k BTU Gross Input, 162k BTU DOE Capacity, 141k BTU Net IBR Capacity. Includes Circulator.
$4,516.43
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Weil-McLain 381359052
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 222k BTU Gross Input, 189k BTU DOE Capacity, 164k BTU Net IBR Capacity. Includes Circulator.
$4,933.81
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Weil-McLain 381359012
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 222k BTU Gross Input, 189k BTU DOE Capacity, 164k BTU Net IBR Capacity. Includes Circulator.
$4,834.00
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Weil-McLain 381359100
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 67k BTU Gross Input, 56k BTU DOE Capacity, 49k BTU Net IBR Capacity. Includes Circulator.
$2,552.93
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Weil-McLain 381359102
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 100k BTU Gross Input, 85k BTU DOE Capacity, 74k BTU Net IBR Capacity. Includes Circulator.
$2,793.79
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Weil-McLain 381359104
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 133k BTU Gross Input, 113k BTU DOE Capacity, 98k BTU Net IBR Capacity. Includes Circulator.
$3,144.60
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Weil-McLain 381359105
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 133k BTU Gross Input, 113k BTU DOE Capacity, 98k BTU Net IBR Capacity. Includes Circulator.
$3,144.60
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Weil-McLain 381359106
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 166k BTU Gross Input, 141k BTU DOE Capacity, 123k BTU Net IBR Capacity. Includes Circulator.
$3,616.00
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Weil-McLain 381359107
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 166k BTU Gross Input, 141k BTU DOE Capacity, 123k BTU Net IBR Capacity. Includes Circulator.
$3,615.09
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Weil-McLain 381359108
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 200k BTU Gross Input, 170k BTU DOE Capacity, 148k BTU Net IBR Capacity. Includes Circulator.
$4,019.01
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Weil-McLain 381359109
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Ratings: 200k BTU Gross Input, 170k BTU DOE Capacity, 148k BTU Net IBR Capacity. Includes Circulator.
$4,019.01
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Burnham STMX200N-RH-KA
Floor Mounted, Cast Iron Boiler with Step-opening Gas Valve. Ships Packaged. Ratings: 200K BTU Gross Input, 165K BTU DOE Capacity, 124K BTU Net IBR Capacity.
$5,974.00
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Burnham STMX100N-RH-PA
Floor Mounted, Cast Iron Boiler with Step-opening Gas Valve. Ships Packaged. Ratings: 100K BTU Gross Input, 82K BTU DOE Capacity, 62K BTU Net IBR Capacity.
$4,391.00
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Burnham X-205N-GH
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Included Grundfos Circulator and LWCO. Ratings: 140K BTU Gross Input, 117K BTU DOE Capacity, 102K BTU Net IBR Capacity.
$2,881.00
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Burnham X-206N-GH
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Included Grundfos Circulator and LWCO. Ratings: 175K BTU Gross Input, 146K BTU DOE Capacity, 127K BTU Net IBR Capacity.
$3,471.00
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Burnham X-206N-TH
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Included Taco Circulator and LWCO. Ratings: 175K BTU Gross Input, 146K BTU DOE Capacity, 127K BTU Net IBR Capacity.
$3,471.00
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Burnham X-208N-TH
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Included Taco Circulator and LWCO. Ratings: 245K BTU Gross Input, 205K BTU DOE Capacity, 178K BTU Net IBR Capacity.
$4,247.00
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Burnham X-209N-TH
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Included Taco Circulator and LWCO. Ratings: 280K BTU Gross Input, 234K BTU DOE Capacity, 203K BTU Net IBR Capacity.
$4,574.00
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Burnham X-203N-TH
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Included Taco Circulator and LWCO. Ratings: 70K BTU Gross Input, 59K BTU DOE Capacity, 51K BTU Net IBR Capacity.
$2,481.00
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.
Learn More About Burnham X-204N-TH
Floor Mounted, Cast Iron Boiler with Single Stage Gas Valve. Ships Packaged. Included Taco Circulator and LWCO. Ratings: 150K BTU Gross Input, 88K BTU DOE Capacity, 77K BTU Net IBR Capacity.
$2,639.00
Factory-Direct
Free Shipping & Lift Gate
Learn More About Free Freight
Free Shipping & Lift Gate
*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 may apply, see our full shipping policy for more details.
2% Check Discount
Learn More About 2% Check Discount
2% Check Discount
Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.

Natural gas cast iron boilers come in both hot water and steam mediums, with a variety of venting options. Shop the top brands and find the perfect cast iron natural gas boiler for your needs.