AquaPlus85 82 Gal. Indirect-Fired Water Heater, Residential, 300,000 BTU

High-Capacity Indirect-Fired Water Heating – Engineered for Demanding Applications

The Weil-McLain Aqua-Plus 85 is a high-performance indirect water heater designed to meet the domestic hot water requirements of large residential systems and light commercial installations. With an 82-gallon nominal storage capacity and a 300,000 BTU heat transfer rating, it supports high first-hour delivery and rapid recovery when paired with a hydronic boiler.

This model utilizes a corrosion-resistant 316L stainless steel tank and an internal 304L stainless steel heat exchanger, delivering high output with reliable, long-term performance. Suitable for closed-loop hydronic systems, the Aqua-Plus 85 ensures stable operation with minimal maintenance in high-demand settings.

Key Engineering Features

• 82-Gallon Nominal Capacity – Supports peak demand in large residential and light commercial applications
• 300,000 BTU/hr Heat Input – Efficient energy transfer via large surface area coil for high recovery rates
• 316L Stainless Steel Tank – Welded construction provides corrosion resistance and long service life
• 304L Stainless Steel Heat Exchanger – Fully immersed coil maximizes heat transfer from boiler circuit
• Factory-Installed Magnesium Anode – Provides cathodic protection against localized corrosion
• 2” CFC-Free Polyurethane Foam Insulation – Minimizes standby losses and improves thermal efficiency
• Adjustable Base – Accommodates uneven mechanical room floors, ensuring level installation
• Pre-Configured Sensor Port & Thermostat Wiring – Simplifies control integration and boiler call signaling

Technical Specifications

• Model: Aqua-Plus 85
• Storage Volume: 82 gallons
• Heat Exchanger Surface Area: 20.8 ft²
• First-Hour Rating: 335 GPH @ 100°F rise
• Max Working Pressure: 150 psi (tank), 145 psi (coil)
• Connections: 1” NPT DHW, 1” NPT boiler supply/return
• Height: 60”
• Diameter: 26”
• Warranty: Limited lifetime on tank (residential use); 2 years on other components

Installation & Field Considerations

Installation of the Aqua-Plus 85 requires integration with a closed-loop boiler system capable of delivering sufficient flow and temperature to the internal coil. All piping must be installed per local code and in accordance with system schematics provided in the manufacturer’s technical manual. Relief valve, drain valve, and mixing valve are required field components. Dielectric unions and isolation valves are recommended.

This product is intended for professional installation by licensed mechanical contractors. Systems with hard water or high usage frequency should be evaluated for periodic flushing and anode replacement schedule.

Contractor Use Case

The Aqua-Plus 85 is engineered for high-demand installations such as multi-bath residences, light commercial buildings, or systems with large tub-fill or laundry loads. With its robust coil and insulated tank assembly, it provides reliable output and reduced energy waste when configured with high-efficiency modulating boilers or conventional cast iron systems.