AB-155C AquaBalance Combination Wall Mount Gas Boiler, 125,000 BTU (NG) T6 Pro Smart Wi-Fi Programmable Thermostat, 2H/2C – Labor cost included


Great things really do come in small packages. The new AquaBalance™ combi-boiler combines the unmatched reliability of Weil-McLain with the warmth of high-efficiency space heating and the convenience of on-demand domestic hot water. All in one elegant, space-saving package.

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  • Description


  • 95% annual fuel utilization efficiency (AFUE) – low fuel usage, saves energy
  • Natural or Propane (LP) gas operation – factory shipped as NG, optional LP conversion kit
  • Compact design – increases placement options
  • Heavy gauge insulated jacket – provides quiet operation
  • 10-to-1 turn down ratio – precisely matches minimal energy usage to the immediate system need
  • Low NOx rated – low emissions level achieved South Coast certification
  • Single tube, large diameter, ASME certified 316L Stainless Steel heat exchanger
  • Pre-wired, plug-in ready electrical design
  • Contractor friendly removable sides – makes service clean and easy
  • Wall mounting bracket and hardware
  • Honeywell® boiler control with digital display
  • Commercial grade 120V power cord with 3 prong plug
  • Unique 3-in-1 vent adapter – approved to accept PVC, CPVC, SS or PP vent materials
  • Multiple vent options – direct vent with 2 pipes or concentric, through sidewall or roof
  • Internal condensate trap
  • 24VAC thermostat relay
  • Factory tested
  • Internal 3-speed circulator
  • DHW flat plate heat exchanger



Fuel Type: Natural Gas
BTU Input: 155000
BTU Output: 125000
DOE Rating: 144000
IBR Rating: 125000
System Type: Hydronic (Water)
Height (Inches): 27.56″
Efficiency: 95%
Vent Type: Direct Vent
Features: Condensing

Combo DHW

EI/Spark Ignition

Wall Mounted

Energy Star Rated: Yes
Warranty: 10 Year Limited Warranty on Heat Exchanger for Residential Use/ 5 Years Limited on Heat Exchanger for Commercial Use/ 2 Years Limited on Parts