120,000 BTU Exterior Natural Gas Tankless Water Heater

The V53DeN is Rinnai's exterior, natural-gas tankless water heater, built in aluminum for a compact wall-mounted install that suits non-traditional spaces such as crawl spaces and attics. It is listed for indoor or outdoor location.

It is rated for a maximum input of 120,000 BTU and a minimum flow rate of 0.3 gallons per minute, with an energy factor of 0.82 and a Uniform Energy Factor of 0.81. The unit runs on 120-volt power and draws 50 watts. Overall dimensions are 21.8 inches high, 14 inches wide, and 7.9 inches deep, and it weighs 29.7 pounds.

Installation is wall-mounted and requires professional service. The unit is direct vented, rated between 115°F and 120°F, Title 24 listed for California, and AHRI and CSA certified. It has no pilot light and no storage tank to heat and reheat, so it runs only when hot water is needed. The temperature controller is sold separately. A qualified installer should confirm clearances, gas-line sizing, and local code before installation.

This listing is for the water heater itself. Gas piping, electrical connections, mounting hardware, and venting materials are not included unless stated.

Rinnai's limited warranty covers the heat exchanger for 10 years, parts for 5 years, and labor for 1 year.

Delivery and returns: this water heater ships free by ground delivery and arrives within the window shown above. If it is not the right fit, return it free within 30 days in its original packaging.

• Installation and Clearances

  The source lists this unit as wall mounted and suitable for compact or non-traditional spaces such as crawl spaces and attics. Confirm the installation site, clearances, mounting method, weather exposure, and local code requirements with a qualified professional. The source page does not publish a numerical clearance schedule.

• Venting Requirements

  Direct venting is required. Confirm the approved vent system, termination, clearances, and route in the installation documentation before ordering parts. A qualified installer should size and install the venting for this gas appliance and verify the completed installation.

• Natural Gas Supply

  This single variant is the natural-gas configuration. The source lists maximum input of 120,000 BTU but does not publish a gas-line size in the page specifications. Have a qualified installer verify pressure, supply capacity, connections, and local requirements.

• Flow and Temperature Rise

  The source lists a 0.3 GPM minimum flow and a maximum-flow field of 5.3 without a unit in the specification row. Its ground-water graphic maps approximately 2.3 to 4.6 GPM across listed water temperatures. Actual delivery depends on temperature rise, incoming water, and simultaneous demand.

• Controls and Recirculation

  The page says the associated temperature controller is sold separately and does not publish a complete controller compatibility or recirculation specification. Plan controls and any recirculation equipment with the installer, and verify accessories and wiring before ordering. Do not assume a controller or pump is included.

• Efficiency and Power

  Source-listed energy factor is 0.82 and uniform energy factor is 0.81. The unit is described as operating only when hot water is needed, and the specification table lists 50 Watt and 120 Volt. Confirm electrical requirements and efficiency documentation for the intended installation.

• Descaling and Maintenance

  The source page does not publish a descaling procedure or maintenance interval. Water quality and use can affect service needs. Follow the current installation and service documentation for flushing, descaling, and other maintenance, and use a qualified technician when required.

• Warranty Terms

  Residential warranty is listed as limited 10 years on the heat exchanger, 5 years on parts, and 1 year on labor. The source page also shows a 10-year limited warranty length. Review the written warranty, registration requirements, and installation conditions before purchase.

• What Ships

  The source page identifies the tankless heater but does not publish a complete box-contents list. The temperature controller is specifically sold separately. Confirm included fittings, venting, controls, and other required installation materials before scheduling the work.

Good to know

• 14″ W × 7.9″ D × 21.8″ H; wall mounted.
• Natural-gas configuration; verify supply sizing.
• Direct vent required; confirm clearances and termination.
• Temperature controller sold separately; verify accessories.
• Professional installation is required for gas, venting, electrical, and water connections. Have a qualified installer confirm local code requirements before installation.
• Tankless water heater only. Installation materials, venting components, and other items shown are not included unless stated.