Ultra 105 - 81,000 BTU Output High Efficiency Boiler - Series 4 (Natural Gas or Liquid Propane)

Weil‑McLain Ultra 105 – 105 MBH Input High‑Efficiency Condensing Boiler (94 % AFUE)

The Ultra 105 is a cast‑aluminum condensing gas boiler optimized for high-efficiency hydronic heating. Featuring a factory-coated aluminum primary heat exchanger paired with a stainless steel burner and variable-speed blower, it delivers up to 94% DOE AFUE, producing 94 MBH output from a 105 MBH input. It's ENERGY‑STAR certified and designed for sealed combustion with direct or concentric venting systems ranging 2″–3″ diameter :contentReference[oaicite:1]{index=1}.

???? Core Features & Contractor Benefits Modulating Burners & Control: 5:1 turndown ratio with direct spark ignition, stainless mesh burner, negative pressure gas valve, and variable-speed blower manage combustion noise and efficiency supplyhouse.com +6 weil-mclain.com +6 weil-mclain.com +6 . U-Control Platform: Includes outdoor reset, domestic hot water priority, multi-zone capability, alarm indicators, and a color LCD—MICRO-processor based for simplified setup and diagnostics acwholesalers.com +9 weil-mclain.com +9 weil-mclain.com +9 . Quiet & Clean Design: High-grade stainless steel burner and venturi air mix ensure whisper-quiet combustion and low NOx emissions powerequipmentdirect.com +4 weil-mclain.com +4 supplyhouse.com +4 . Efficient Condensate Management: Nano-coated aluminum exchanger and PVC-compatible venting reduce buildup and simplify service acwholesalers.com +4 ecomfort.com +4 thegranitegroup.com +4 . Warranty: 12-year limited on the heat exchanger; standard 2-year parts; registration adds up to 5 years parts coverage afsupply.com +1 afsupply.com +1 . ???? Technical Specifications Specification Value Input 105 MBH DOE Heating Output 94 MBH Net I=B=R Output 82 MBH AFUE 94% Vent Size 2″ or 3″ PVC/CPVC/PP/SS Dimensions (L×W×H) 22 13/16″ × 19 15/16″ × 43 3/4″ powerequipmentdirect.com +4 thegranitegroup.com +4 supplyhouse.com +4 weil-mclain.com +1 weil-mclain.com +1 Water Connections 1″ supply/return, gas connection ½″ Weight 198 lb ???? Installation Notes Sealed combustion: Clockwork venting through wall or roof; includes a 3-in-1 adapter; requires condensate drain and neutralizer when vented in PVC afsupply.com +4 thegranitegroup.com +4 goatlantic.com +4 . Control Wiring & Access: Comes with pre-wired components and color-coded U-Control board; aluminum jacket is removable for service. System Compatibility: Compatible with baseboard, panel radiators, or radiant floor systems. Supports indirect DHW tanks, outdoor reset, and multiple circulators. ???? Contractor Summary Compact footprint and direct-vent capability make the Ultra 105 suitable for mechanical room retrofits or new builds. Full-service access, advanced diagnostics, and modulation make it ideal for installation and long-term efficiency. Sealed combustion and vent & install flexibility align with modern code requirements for sealed systems and flexible piping. The Weil‑McLain Ultra 105 combines high efficiency, advanced controls, and professional-level serviceability—making it a strong choice for contractors specifying high-performance hydronic boilers.