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Weil Mclain Products

Weil Mclain 383500703

383-500-703 Ultra 155 Natural Gas Ultra Efficient Condensing Gas Boiler


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Quick Specs: View More

  • Width: 22-5/8"
  • Height: 41-1/8"
  • Depth: 19"

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Discontinued No longer available.

Weil McLain Ultra UG-155-S3-UE, Natural Gas Series 3 High Efficiency Condensing Hot Water Residential boilers feature AFUE efficiency up to 95.6% . These are some of the highest efficiencies in the industry, however, Ultra Series boilers, when used in common low temperature applications have annual efficiencies of 98.0%. Besides being Ultra High Efficient, the Ultra boiler is environmentally friendly. Available at AppliancesConnection


  • Cast Aluminum Mono Block - aluminum provides 10 times better and faster heat transfer than stainless steel
  • Variable Speed Blower Assembly - constantly matches combustion output to your heating needs
  • Control Panel with Digital Display - u-Control user's Interface Module is provided to display system operating status and fully adjustable parameter values as well as diagnostic codes for easy troubleshooting and optimum system performance
  • Venture Mixing System with Air Silencer - precisely mixes air and gas providing higher efficiency and quiet operation
  • Made in the USA
  • Stainless Steel Burner with woven steel fiber mesh
  • Outdoor temperature sensor
  • Direct Spark Ignition
  • Automatic air vent
  • Pressure gauge
  • Condensate drain assembly
  • NTC temperature sensors on the boiler supply/return and flue
  • 120V Power switch
  • Low water protection
  • Domestic hot water priority
  • High temperature limit protection
  • Boiler freeze protection
  • Factory tested 


  • Fuel Type:  Propane/Natural Gas
  • System Type:  Hydronic (Water)
  • Vent Size:  3"
  • Water Connection:  1"
  • Gas Connection:  1/2"
  • BTU Input:  155000
  • BTU Output:  123000
  • Boiler Type:  High Efficiency
  • Width:  22-5/8"
  • Height:  41-1/8"
  • Application:  Heating
  • Depth:  19"
  • Vent Type:  ABS

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  • Brand:Weil Mclain
  • SKU:383500703
  • UPC:672619185944
  • Stock Id:229514
  • Product Number:383500703


  • Fuel Type:Propane/Natural Gas
  • BTU Output:123000
  • BTU Input:155000


  • Height:41-1/8"
  • Width:22-5/8"
  • Depth:19"

    Technical Details

  • Energy Star:No
  • Application:Heating
  • System Type:Hydronic (water)
  • Vent Size:3"
  • Water Connection:1"
  • Gas Connection:1/2"
  • Boiler Type:High Efficiency
  • Weight:150.00 lbs