Weil-McLain Ultra Series 4 399,000 BTU Condensing Gas Boiler

Weil-McLain Ultra Series 4 399,000 BTU 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

• Cast aluminum coated heat exchanger
• Designed to operate in low temperature condensing applications
• Outdoor reset and domestic hot water priority
• Modulates with 5:1 turn-down ratio
• High grade stainless steel burner features quiet operation
• U-Control gives the power for easy set-up and maintenance
• Multiple set-up and zone options
• System sensing recognizes system and outdoor temperatures
• Temperature management for up to three different set-points
• Control multiple boilers from a single control panel
• Standard screen messages provide service alerts and maintenance reminders

What Our Experts Think

• Top‑tier efficiency: The Weil‑McLain Ultra Series 4 399,000 BTU Condensing Gas Boiler delivers industry‑leading condensing performance (typically up to ~95% AFUE), maximizing heat output while minimizing fuel costs.

• High heating capacity: With 399,000 BTU/h, this model powers large homes, multifamily buildings, and light commercial spaces requiring substantial hydronic heat.

• Smooth, quiet operation: Advanced burner and heat‑transfer design provide stable combustion with reduced noise and more even heat delivery.

• Durable & service‑friendly: Corrosion‑resistant heat exchanger and accessible service points support long life and easier maintenance for technicians.

Product Q&A

• What type of boiler is this?
  A high‑efficiency condensing gas boiler that uses a secondary heat exchanger to extract extra energy from combustion exhaust.

• Where is it best used?
  Ideal for large residential properties, multifamily units, schools, offices, and light commercial facilities with significant heating demand.

• What heating systems does it support?
  Works with hydronic baseboard, radiant floor systems, fan coils, and other hot‑water distribution loops.

• What fuel does it use?
  Natural gas (propane conversion kits may be available from Weil‑McLain via a qualified HVAC technician).

• Does it need special venting?
  Yes — condensing boilers typically use PVC/CPVC or polypropylene venting because of lower exhaust temperatures and condensate handling.

Maintenance Tips

• Annual professional service: Have a licensed HVAC technician inspect and tune the boiler before each heating season — checking the burner, heat exchanger, controls, and combustion performance.

• Check condensate drainage: Make sure condensate outlets and trap lines are clear and properly pitched to avoid buildup or freeze issues.

• Monitor system pressure: Maintain proper boiler pressure and expansion tank condition as recommended.

• Clean intake & exhaust terminations: Keep vents free of debris and obstruction for safe combustion airflow.

• Inspect for leaks: Check around valves, fittings, and piping periodically for signs of water or gas leaks.

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