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Weil McLain Ultra Gas S3 CT Gas Boiler Print E-mail

Ultra Gas S3 CT Gas Boiler weilmclain_logo

Models: UG-80, UG-105, UG-155, UG-230, UG-299, UG-399


Boiler Intelligence for Every Heating Need

  • Optimal Efficiency for Multiple Temperatures
  • Quick System Presets to Match any Application
  • Seamless Multiple Boiler Control



  • Gas fired water boiler with cast aluminum heat exchanger
  • Venturi mixing body mixes air and gas providing higher efficiency
  • Designed to operate in low temperature condensing applications
  • Outdoor reset and domestic hot water priority standard
  • Negative regulated gas valve precisely delivers gas to the boiler
  • U-Control gives you the power for easy set-up and maintenance
  • Modulates with 5 to 1 turn-down ratio
  • Variable speed motor matches combustion output to heating needs
  • High grade stainless steel burner features quiet operation, high efficiency, and cleaner combustion for low NOx applications


ModelA.G.A. Input (MBH)DOE Heating Capacity (MBH)Net I=B=R Ratings (MBH)Min. Vent SizeAnnual Fuel Utilization Efficiency (AFUE)
UG-80 80 71 62 2 or 3 in. PVC/CPVC 93.5%
UG-105 105 94 81 2 or 3 in. PVC/CPVC 94.0%
UG-155 155 139 123 3 in. PVC/CPVC 94.0%
UG-230 230 207 183 3 or 4 in. PVC/CPVC 94.1%
UG-299 299 270 234 4 in. PVC/CPVC 92.5%
UG-399 399 365* 317 4 in. PVC/CPVC 91.7%*

*Combustion Efficiency

Sentinel X100 Water Treatment included with boiler
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