Weil-McLain AB-120H AquaBalance Series 2 120,000 BTU Heat-Only Condensing Gas Boiler

Weil-McLain AB-120H AquaBalance Series 2 120,000 BTU Heat-Only Condensing Gas Boiler

Weil-McLain is a leading North American Brand of hydronic comfort heating systems for residential, commercial and institutional buildings, since 1881. Contractors, engineers, architects, homeowners, and facility managers alike rely on Weil-McLain boilers for their comfort heating needs. Installed in homes, offices, schools, restaurants, hotels, and other facilities throughout North America, the Weil-McLain brand is among the most trusted and often used in the building industry.

Features

• Compact design to increase placement options
• Heavy gauge insulated jacket provides quiet operation
• Contractor-friendly removable sides
• Pre-wired, plug-in ready electrical design
• Commercial grade 120V power 6' cord with 3 prong plug
• 24 VAC thermostat relay, fuse protected with prewired terminal strip
• Honeywell control with digital display
• Wall mounting bracket and hardware included
• Unique "3-in-1" vent adapter readily accepts PVC, CPVC, SS, or PP vent materials
• Multiple vent options includes direct vent, 2 pipes or concentric, through roof or sidewall
• Strategically placed sensors used instead of additional bulky boiler controls

What Our Experts Think

• Efficient condensing design: The Weil‑McLain AB‑120H AquaBalance Series 2 120,000 BTU Heat‑Only Condensing Gas Boiler uses condensing technology to extract more heat from combustion, lowering fuel costs compared to non‑condensing units.

• Heat‑only focus: Built to deliver space heating only, it pairs well with a separate domestic hot‑water system, keeping design simple and efficient.

• Quiet, dependable performance: Smooth combustion and well‑engineered components provide consistent warmth and stable operation.

• Durable and service‑friendly: Corrosion‑resistant heat exchanger and accessible service points make maintenance easier and help extend service life.

Product Q&A

• What does “heat‑only” mean?
  The boiler provides space heating only — it does not produce domestic hot water; a separate water heater or indirect tank is required for DHW.

• What fuel does it use?
  Natural gas; a licensed HVAC tech can install a propane conversion kit if LP gas is needed.

• Where is this best used?
  Ideal for single‑family homes or light commercial systems with separate hot water sources that need efficient hydronic heating.

• How efficient is it?
  Condensing design boosts heat extraction from exhaust gases, improving overall system efficiency and lowering operating cost.

Maintenance Tips

• Annual professional check: Have a licensed HVAC technician inspect and tune the boiler before the heating season — burner, heat exchanger, condensate system, and controls.

• Clear condensate lines: Ensure condensate drains and traps are clear and properly pitched to avoid clogs or freeze issues.

• Monitor pressure & water levels: Maintain correct boiler pressure and verify expansion tank function.

• Clean vents & intakes: Keep air intake and exhaust terminations free of debris to ensure safe operation.

• Inspect for leaks: Periodically check valves, joints, and piping for signs of water or gas leaks.

• Maintain water quality: Use recommended inhibitors and schedule periodic system flushing to reduce scale and extend component life.