Noritz 8.3 GPM 180,000 BTU Residential Natural Gas Outdoor Tankless Water Heater (.82 UEF)

The Noritz NR83-OD-NG 8.3 GPM 180,000 BTU Residential Natural Gas Outdoor Tankless Water Heater delivers dependable, on-demand hot water while helping reduce energy consumption by heating water only when it is needed. Unlike traditional storage tank water heaters that continuously heat and store a limited supply of hot water, the NR83-OD-NG provides an endless supply of hot water without standby energy loss, making it an excellent choice for larger homes with multiple bathrooms and higher simultaneous hot water demands.

Designed exclusively for outdoor installation, the NR83-OD-NG requires no vent piping, helping simplify installation while preserving valuable indoor space. Delivering up to 180,000 BTU of natural gas heating power and a maximum flow rate of 8.3 gallons per minute, this compact wall-mounted tankless water heater combines commercial-grade durability, advanced safety features, and precise temperature control to provide years of reliable residential hot water performance.

Product Features:

• 180,000 BTU Maximum Input: Provides powerful natural gas heating capacity for larger residential hot water applications.
• Up to 8.3 GPM Flow Rate: Delivers continuous hot water for multiple showers, sinks, dishwashers, washing machines, and other fixtures simultaneously, depending on incoming water temperature and household demand.
• Outdoor Installation: Factory-designed exclusively for outdoor installation, eliminating the need for vent piping while helping simplify installation.
• Non-Condensing Design: Provides dependable on-demand performance with a Uniform Energy Factor (UEF) of 0.82 while heating water only when needed.
• Commercial-Grade Copper Heat Exchanger: Manufactured with commercial-grade copper tubing approximately 25% thicker than many standard residential heat exchangers for enhanced durability, efficient heat transfer, and long service life.
• Fully Modulating Burner: Automatically adjusts between approximately 18,000 and 180,000 BTU to help maintain consistent outlet water temperatures while improving fuel efficiency.
• Adjustable Temperature Settings: Includes a remote thermostat with adjustable temperature settings from 115°F to 140°F for precise residential hot water control.
• Quick Connect Compatible: Two identical NR83 units can be connected using the optional Noritz Quick Connect Cord to nearly double available hot water capacity without requiring an additional controller.
• Scale Detection Reminder: Built-in maintenance reminder helps notify homeowners when routine flushing and descaling should be performed to maintain peak efficiency and long-term performance.
• Built-In Freeze Protection: Helps protect the heat exchanger during freezing temperatures when installed according to manufacturer requirements and connected to electrical power.
• Advanced Safety Features: Includes flame sensing, overheat prevention, fan rotation monitoring, lightning protection, temperature lockout, high elevation adjustment, and advanced self-diagnostic monitoring.

What Is an Isolation Valve Kit?

An isolation valve kit is a recommended accessory for every tankless water heater installation. Isolation valves connect to the hot and cold water lines, allowing the water heater to be isolated for flushing, descaling, maintenance, or servicing without shutting off water to the rest of the home.

Routine flushing removes mineral deposits that naturally accumulate inside the heat exchanger, especially in areas with hard water. Installing isolation valves makes annual maintenance significantly easier while helping preserve efficiency, improve performance, and extend the service life of the water heater.

Short vs. Long Isolation Valve Kit

For the Noritz NR83-OD-NG, only one isolation valve kit is required depending on your installation layout.

• IK-WV-200-5-TH-S Short Isolation Valve Kit: Recommended for installations where available space is limited or a compact plumbing arrangement is preferred.
• IK-WV-200-5-TH-L Long Isolation Valve Kit: Ideal when additional clearance is available, providing easier access for future maintenance and servicing.

Both isolation valve kits include durable 3/4-inch threaded hot and cold isolation valves together with a lead-free pressure relief valve. The correct kit depends on the available installation space and plumbing layout.

Understanding Tankless Water Heater Sizing

Unlike traditional storage tank water heaters, tankless water heaters are sized using flow rate (GPM) and temperature rise rather than storage capacity. Flow rate represents the amount of hot water the unit can produce each minute, while temperature rise is the difference between the incoming groundwater temperature and your desired outlet temperature.

Always size a tankless water heater using your area's winter groundwater temperature, since colder incoming water requires more heating capacity and reduces the maximum available flow rate.

For example, if your desired hot water temperature is 120°F and your incoming groundwater temperature is 50°F, the required temperature rise is:

120°F − 50°F = 70°F Temperature Rise

Use the Noritz flow rate chart included with the product literature to determine the expected hot water output at your required temperature rise. This helps ensure the water heater is properly sized for your household's peak simultaneous hot water demand.

Warranty

The NR83-OD-NG includes Noritz's residential limited warranty featuring a 12-year heat exchanger warranty for standard residential installations, a 5-year parts warranty, and a 1-year reasonable labor warranty. When installed with a controlled recirculation system using a minimum aquastat pump control, the heat exchanger warranty remains 12 years or 6,500 operational hours, whichever occurs first. Always verify natural gas supply, installation location, electrical requirements, water quality, local plumbing and mechanical codes, and all required accessories prior to installation.