Noritz 6.6 GPM 140,000 BTU Residential Propane Outdoor Tankless Water Heater (.82 UEF)

The Noritz NR662-OD-LP 6.6 GPM 140,000 BTU Residential Propane Outdoor Tankless Water Heater provides an energy-efficient way to enjoy continuous hot water without the limitations of a traditional storage tank. Instead of storing hot water that can eventually run out, the NR662-OD-LP heats water only when a hot water fixture is turned on, helping reduce standby energy loss while providing an endless supply of hot water for everyday household needs.

Designed exclusively for outdoor installation, the NR662-OD-LP requires no additional venting, making it an excellent solution where indoor installation space is limited. With up to 140,000 BTU of propane heating power, a maximum flow rate of 6.6 gallons per minute, and a compact wall-mounted cabinet, this residential tankless water heater is ideal for condominiums, townhomes, apartments, and homes with one to two bathrooms. Its commercial-grade copper heat exchanger, built-in freeze protection, and user-friendly temperature controls provide dependable hot water performance for years to come.

Product Features:

• 140,000 BTU Maximum Input: Provides dependable propane heating capacity for residential hot water applications.
• Up to 6.6 GPM Flow Rate: Delivers continuous hot water for multiple fixtures, including showers, faucets, dishwashers, and washing machines, depending on incoming water temperature and household demand.
• Outdoor Installation: Designed exclusively for outdoor installation, eliminating the need for additional vent piping while simplifying installation.
• Non-Condensing Design: Delivers reliable performance with a Uniform Energy Factor (UEF) of 0.82 while heating water only when needed.
• Commercial-Grade Copper Heat Exchanger: Built with a durable copper heat exchanger for dependable long-term residential performance.
• Compact Wall-Mounted Cabinet: Saves valuable indoor space while providing easy outdoor installation.
• Adjustable Temperature Settings: Factory default temperature is 120°F with adjustable settings from 115°F to 140°F using the remote controller.
• Fully Modulating Burner: Automatically adjusts between approximately 15,000 and 140,000 BTU to maintain consistent outlet water temperatures while reducing unnecessary fuel consumption.
• Freeze Protection: Built-in freeze protection helps safeguard the unit in outdoor temperatures as low as -4°F when installed according to manufacturer instructions.
• Recirculation Compatible: Compatible with external hot water recirculation systems when properly designed and installed.
• Built-In Safety Features: Includes flame sensor, overheat prevention, fan rotation monitoring, lightning protection, temperature lockout, high elevation adjustment, and self-diagnostic display.

What Is an Isolation Valve Kit?

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

Regular flushing helps remove mineral scale that naturally accumulates inside the heat exchanger, especially in areas with hard water. Installing isolation valves makes this routine maintenance much easier while helping maintain performance, improve efficiency, and extend the life of the water heater.

Short vs. Long Isolation Valve Kit

For the Noritz NR662-OD-LP, only one isolation valve kit is required depending on the available installation space.

• IK-WV-200-5-TH-S Short Isolation Valve Kit: Recommended when installation space is limited or a compact plumbing layout 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 along with a lead-free pressure relief valve. The appropriate kit depends on your installation layout and available working space.

Understanding Tankless Water Heater Sizing

Unlike traditional storage tank water heaters, tankless water heaters are sized using flow rate (GPM) and temperature rise, not 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 hot 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 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 simultaneous hot water demand.

Warranty

The NR662-OD-LP includes Noritz's residential limited warranty featuring a 12-year heat exchanger warranty for standard residential use, a 5-year parts warranty, and a 1-year reasonable labor warranty. When used with a recirculation system, the heat exchanger warranty is 3 years. Always verify propane fuel supply, installation location, water quality, electrical requirements, local plumbing and mechanical codes, and all required accessories prior to installation.