Heat Exchanger Watertube Stainless Steel Condensing
Size Range 300 - 4,000 MBH
AHRI Boiler Efficiency +97.5%*
Turndown Full Modulation (10:1)*
Applications Variable Volume, Full Flow, Primary / Secondary
  *Efficiencies & Turndown vary by unit size

Torus watertube boilers and water heaters bring next level performance in a small compact footprint to today’s applications. The RBI tradition of high quality, performance equipment in a user-friendly design continues with Torus.

Incorporating all industry-proven components including HEATNET 3.0 touchscreen cascade control, Tru-Flow fuel/air coupling system with 10:1 turndown and capacities to 4000 MBH Torus has the solution for all commercial installations.

The Torus uses a pressure driven mixing system with no moving parts to provide a reliable maximum of 10:1 turndown, without lowering the CO2% while avoiding nuisance ignition lockouts.


300 - 1000 MBH


1250 - 4000 MBH

Features and Benefits

Small Torus

300 - 1000 MBH


1250 - 4000 MBH

  • 300 – 4000 MBH
  • Full Modulation (10:1)*
  • 4 Pass Double-Row Watertube Heat Exchanger (160 psi/ASME (H & HLW) Stamp)
  • 316L Stainless Steel Watertube Heat Exchanger
  • Variable Volume, Full Flow and Primary/Secondary
  • Sika Flow Switch (Flow Sensor Optional)
  • HEATNET 3.0 Integrated Control Platform
  • Touchscreen Programming and Diagnostics
  • Modbus, LonWorks and BACnet BMS Integration
  • Category II and IV (up to 160’)
  • PVC/CPVC, Polypropylene and Stainless Steel Vent Approved
  • Warranty (Heat Exchanger): 10-year Boiler; 5-year Water Heater
  • NG/LP/Dual Fuel
  • Easy Maintenance and Installation
  • Outdoor Installation
  • Top Inlet/Outlet Water Connections (Optional with Indoor Models Only)
  • Low Nox
*Efficiencies & Turndown vary by unit size

Have Questions?

Contact a Sales Representative

Heat Exchanger

Torus heat exchangers are designed for optimum performance and durability. Made from an industrial quality 316L stainless steel Torus heat exchangers are reliable and robust while being very resistant to both thermal shock and acidic condensate.

A unique 4-pass design works in concert with a new multichannel manifold and increased tube diameters resulting in ultra-high efficiency with very low pressure drop.

Torus heat exchangers are manufactured with an industrial quality 316L stainless steel through a process called tube hydroforming. Tube hydroforming allows the shaping of stainless steel tubes that are not only stronger and lighter but also have a higher quality surface than competitive heat exchangers maximizing both performance and durability in a compact design.

Hydroforming insures a uniform and consistent gap between the tubes facilitating consistent exhaust gas circulation and uniform heat transfer throughout the entire heat exchanger.

Torus Heat Exchanger

4-Pass Heat Exchanger

Torus heat exchangers use a 4-pass system for maximum efficiency. The unique path of water throughout the heat exchanger is designed to absorb as much heat energy as possible.

  • Pass 1: Return water passes through the first set of inner tubes absorbing residual heat energy.
  • Pass 2: Water passes through the exhaust gas chamber
  • Pass 3: Outer tubes of the combustion chamber
  • Pass 4: Supply water distribution final pass through the inner tubes of the combustion chamber

Gas Train

Torus Heat Exchanger

Bluejet Burner

Torus’ Bluejet burner offers industry leading modulation capacity, flame retention and combustion quality. Whether natural gas or LP gas, BlueJet’s low NOx design works in perfect concert with our Tru-Flow fuel/air system providing consistent reliable operation.

Torus Fuel Line

Symmetric Air/Fuel Coupling

RBI’s state-of-the-art air/fuel coupling combustion control system is instantly responsive and completely adaptable. This unique boiler combustion control system is designed to keep the Torus running safe, clean and efficient. The system reacts to changes in air and instantly compensates fuel supply by adjusting input to maintain a constant air/fuel mixture across the modulation range. The unique design of the air/fuel mixing system ensures a complete and consistent air/ fuel mixture to the burner which increase combustion efficiency and repeatability all while maintaining low emissions.

Torus Sika Sensor


All Torus units include a Sika flow switch and an option Vortex Flow Sensor mounted in a by-pass configuration and mapped to indicate the boiler flow in (gpm). The SIKA flow sensor utilizes vortex technology which is then converted to an electrical signal sent directly to the HEATNET Boiler Management System for real time flow annunciation. The SIKA flow sensor is fully adjustable throughout the boiler model operating range.


Digital Touch Screen Programming

Lead/Lag Cascade (16 Units)

Mixed-Size Unit Communication

Adaptive Modulation

Circular Pump/VFD/Valve Control

BMS Integration

Freeze Protection & Delta T Monitoring

Hybrid/base Load Capability

Priority Boiler Control

Domestic Hot Water Communication

Web-Based Remote Monitoring/Dashboard

Diagnostics and Troubleshooting

Set Points

Exclusive Remote Monitoring Capability with HEATNET Online

Ease of Service

Torus just may be the easiest piece of equipment ever to service. A unique burner door system provides easy access to both the burner and heat exchanger tube bundle. All burner doors come with a slide and hinge mechanism that easily slides outwards offering full access to the combustion chamber for annual inspection and service.

Ratings and Dimensions

Small Torus Torus