Weil-McLain GV90+ Cast Iron - Gas-Fired Hot Water Boiler - 97 MBH - Cast Iron Heat Exchanger - 91.2% AFUE

The GV90+ is part of Weil-McLain’s high-efficiency cast iron boiler line designed for residential hot water heating systems. It combines a durable cast-iron primary heat exchanger with a secondary condensing stainless steel exchanger, delivering 91.2% AFUE efficiency while maintaining cast-iron reliability.

This boiler is built for homeowners who want the longevity of cast iron and the efficiency of modern condensing technology.

🔹 Key Features

• Dual Heat Exchanger Design

  • Cast Iron Primary Exchanger: Proven durability, resists corrosion, and extends system life.

  • Stainless Steel Condensing Secondary Exchanger: Extracts additional heat from flue gases for higher efficiency.

• High Efficiency

  • AFUE: 91.2% (ENERGY STAR® certified in most configurations).

  • Qualifies for rebates in many regions.

• Fuel Type

  • Natural Gas standard, convertible to Propane (LP) with optional kit.

• User-Friendly Controls

  • Integrated control panel with diagnostic codes.

  • Reset function for automatic adjustment based on outdoor temperature (when paired with outdoor reset sensor).

• Flexible Venting Options

  • Can be vented through PVC, CPVC, polypropylene, or stainless steel.

  • Sidewall or vertical venting options allow easy installation in different home layouts.

• Quiet Operation

  • Insulated jacket reduces operating noise.

• Multiple Sizes Available

  • The 97 MBH model is typically suited for medium to larger homes; GV90+ line ranges from ~65 MBH to ~165 MBH input.

🔹 Technical Specifications (97 MBH Model)

🔹 Benefits

• Durability: Cast iron exchangers are known to last decades with proper maintenance.

• Efficiency: Secondary exchanger extracts more heat for lower fuel bills.

• Flexibility: Works with fin-tube baseboard, cast-iron radiators, radiant in-floor heating, or indirect water heaters.

• Low Maintenance: Control system provides diagnostics and reduces service time.

• Quiet & Compact: Fits in basements, utility rooms, or mechanical spaces without excessive noise.

🔹 Considerations

• While more efficient than traditional cast-iron boilers, it’s not as high-efficiency as full stainless condensing boilers (~95–97% AFUE).

• Requires condensate drain because of secondary heat exchanger.

• Initial cost is higher than standard cast-iron non-condensing boilers, but savings come from fuel efficiency and rebates.

✅ Summary:
The Weil-McLain GV90+ 97 MBH Gas-Fired Hot Water Boiler is a premium cast-iron/stainless hybrid design that balances long-term reliability with modern efficiency. At 91.2% AFUE, it’s a solid choice for homeowners who want the proven durability of cast iron but also want to capture some of the energy savings of condensing technology. Best for medium-to-large homes with hydronic baseboard or radiator systems.