Noritz 9.8 GPM 199,900 BTU Residential Natural Gas Outdoor Tankless Water Heater (.82 UEF)

The Noritz NR98-OD-NG 9.8 GPM 199,900 BTU Residential Natural Gas Outdoor Tankless Water Heater delivers continuous, 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 water, the NR98-OD-NG heats water only as it passes through the heat exchanger, eliminating standby energy loss while providing an endless supply of hot water. Its high-capacity performance makes it an excellent choice for larger homes with multiple bathrooms and higher simultaneous hot water demand.

Designed exclusively for outdoor installation, the NR98-OD-NG eliminates the need for vent piping, helping simplify installation while preserving valuable indoor space. Delivering up to 199,900 BTU of natural gas heating power and a maximum flow rate of 9.8 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 dependable residential hot water performance.

Product Features:

• 199,900 BTU Maximum Input: Provides powerful natural gas heating capacity for larger residential homes with high simultaneous hot water demand.
• Up to 9.8 GPM Flow Rate: Delivers continuous hot water for multiple showers, bathtubs, sinks, dishwashers, washing machines, and other fixtures simultaneously, depending on incoming water temperature and required temperature rise.
• Outdoor Installation: Factory-designed exclusively for outdoor installation, eliminating the need for vent piping while simplifying installation and preserving indoor living space.
• Non-Condensing Design: Delivers dependable on-demand performance with a Uniform Energy Factor (UEF) of 0.82 while heating water only when needed.
• Commercial-Grade Copper Heat Exchanger: Built using 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 from approximately 16,000 to 199,900 BTU to maintain consistent outlet water temperatures while maximizing natural gas efficiency.
• Adjustable Temperature Settings: Includes a remote thermostat with adjustable temperature settings from 100°F to 140°F in 5°F increments for precise residential temperature control.
• Quick Connect Compatible: Two identical NR98 Series 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 Function: Built-in maintenance reminder helps notify homeowners when flushing and descaling are recommended to maintain peak performance and extend equipment life.
• Built-In Freeze Protection: Helps protect the heat exchanger during freezing temperatures when installed according to manufacturer guidelines and connected to electrical power.
• Advanced Safety Features: Includes flame sensing, overheat prevention, fan rotation monitoring, lightning protection, thermal fuse protection, temperature lockout, high elevation adjustment, and advanced self-diagnostic monitoring.
• Compact Wall-Mounted Design: Saves valuable indoor floor space while allowing convenient installation and future servicing.

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 and allow 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 buildup that naturally accumulates inside the heat exchanger, especially in areas with hard water. Installing isolation valves makes annual maintenance significantly easier while helping preserve efficiency, maintain reliable performance, and extend the service life of the water heater.

Short vs. Long Isolation Valve Kit

For the Noritz NR98-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, allowing easier 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 tank 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 water 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 provided in 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 NR98-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, outdoor installation requirements, electrical requirements, water quality, local plumbing and mechanical codes, and all required accessories before installation.