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Noritz Extends 12-Year/6,500-Hour Warranty To Tankless Water Heaters in Controlled Recirculation Systems

Eligible Noritz models all feature a commercial-grade heat exchanger that recently demonstrated superior durability in head-to-head tests with rival tankless models


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FOUNTAIN VALLEY, CA (September 22, 2010)—Tankless water heater manufacturer
Noritz America recently extended its 12-year/6,500-hour warranty to residential models used with controlled recirculation systems that deliver hot water more quickly to the tap. The extension applies to all Noritz residential tankless water heater products that feature the company’s durable, commercial-grade heat exchanger. Included are the new NR83-DVC concentric tankless water heater, which made its debut this month, as well as the NR98, NRC111 and NR111.

“Twelve years typically translates into roughly 1.5 hours of water heater combustion per day,” explains Bob Hitchner, Senior Vice President - Sales, Marketing & Business Development for Noritz. “A residential system that circulates warm water for a couple of hours in the morning and another couple of hours in the evening should make it for the full 12 years.”

To qualify for protection under the new residential recirculation warranty, a Noritz tankless water heater must meet the following key stipulations:

  • The unit must have been installed on or after September 1, 2010, and equipped with a controlled recirculation pump system that has been installed in accordance with the Noritz Installation Manual.
  • Water heater operational time must not exceed 12 years, or 6,500 hours, whichever comes first. (Note: Operational hours are the hours of actual usage, as counted and stored in the water heater controller.)
  • The recirculation pump must be controlled by an aquastat, which activates the pump when the water temperature falls below a minimum set point and deactivates it when the water temperature reaches the maximum set point.

Noritz also strongly recommends the usage of demand-type timers and sensors to confine pump activation to peak usage periods, further reducing the load on the water heater.

“We love the luxury and water savings that a well-designed recirculation system can deliver,” says Hitchner. “But we also want homeowners and contractors to use common sense when designing such systems.”

As Hitchner notes, most homes need hot water in the bedroom wing between six and eight o’clock in the morning and eight to eleven o’clock at night. Under these circumstances, the recirculation loop may not be needed for the in-between times; or at least the minimum set point in the loop can be lowered.

Why extend the warranty? Noritz residential tankless models used in controlled recirculation systems were previously excluded from the 12-year warranty because of the heavy demands such systems impose on a water heater, particularly its heat exchanger. If hot water is in constant circulation – to be readily available at the tap or shower – the water heater is operating 24/7 as well.

“We made the decision to extend the warranty after extensively testing our commercial-grade heat exchangers,” says Hitchner. “We clearly demonstrated to ourselves that Noritz commercial heat exchangers could withstand the additional operational time of a recirculation application.”

Begun in 2008, the tests referenced by Hitchner spanned 18 months and involved side-by-side tests of three tankless water heater models: a Noritz NR98-SV and two rival makes and models. To determine the effects of hard water on each unit’s heat exchanger, the water heaters were supplied with untreated city water at a hardness level between 13 and 15 grains per gallon. The units were cycled on and off around the clock, day after day, until failure of the heat exchanger. The two competitive models failed after combustion lives of approximately 1,200 and 2,760 hours. The Noritz NR98-SV with its commercial-
grade heat exchanger lasted 6,700 hours before failing.

Based on these results, Noritz calculated the following life expectancies for the three tested water heaters:



SIMULATed residential life in years

life expectancy vs. noritz (ave.)

average USagE  (1 hr per day)

heavy usage (2 hr per day)

Competitor A



About 80% less

Competitor B



About 60% less

Noritz NR98-SV




TEST PROTOCOL: To estimate product lifespan (in years), Noritz (1) set the temperature for both units to 140 degrees Fahrenheit, (2) supplied both units with untreated city water with hardness levels between 13 grains per gallon (gpg) and 15 gpg, and (3) cycled the water on/off 24 hours a day during the test until a leak in each unit's heat exchanger was detected. The estimated lifespan (in years) of the heat exchanger was calculated as follows: Hours of combustion for each product divided by 365. (This calculation is based on average residential water usage of one hour per day.)

Noritz attributes the superior performance of the NR98-SV test unit to the thicker, commercial-grade copper used in its heat exchanger, as well as to “subtle engineering nuances that improve the water flow through the exchanger,” says Hitchner.

“It’s not good enough to extend a 12-year warranty as just another marketing tool,” he continues. “We needed to know whether our heaters are truly meant for this kind of use. The tests validated that Noritz products with commercial-grade heat exchangers could stand up to the heavy demands of a recirculation system while also outperforming the competition.”

Softening the water: Another major determinant of life expectancy for a water heater is the relative “hardness” of the water supply. Hard water has a high scale content that can leave deposits of calcium, magnesium and bicarbonate on pipe, valves and fittings as well as water heating components. Difficult and costly to remove, these highly insoluble deposits also hurt system efficiency while boosting operating costs.

Water conditioning with a softener can help minimize scale deposits, but a softener is not a viable option in every locale. Because these devices discharge sodium and other chemicals into the water supply, some jurisdictions have prohibited their use. Softeners also require regular maintenance.

A recently unveiled alternative is the Noritz H2FLOW™. This cartridge-based system produces no chemicals or salts, yet achieves a 99.6 percent effectiveness rating in scale prevention. Cartridge replacement is required only once every two years.

H2FLOW technology fights scale buildup by changing the chemical structure of the water as it flows through the device, converting hard minerals into soft particles that will not adhere to plumbing-system components – including the water heater. “By preventing scale buildup, H2FLOW offers the added advantage of maintaining the energy efficiency of the water heater over many years of use,” says Hitchner.

“With the H2FLOW, even homeowners living in hard-water areas can enjoy the convenience of instant hot water with a well-designed controlled recirculation system that enables their tankless water heater to provide years of reliable service,” says Hitchner. “That is the type of system our new warranty extension is meant to protect.” 

For more information on the new residential recirculation warranty and the Noritz lines of residential and commercial tankless water heaters, visit

For editorial assistance, contact Leanne Newman at (519) 756-2709; e-mail:

# # #

NORITZ AMERICA CORPORATION, a subsidiary of Noritz Japan, has corporate offices in Fountain Valley, Calif., as well as in Dallas, Atlanta, Chicago and Hawthorne, N.Y. Offering a full line of tankless water heaters to meet the hot water demands of residential and commercial applications. Noritz supports its products with a national network of skilled representatives and employees who are committed to providing the finest products and services to our communities by helping consumers live in a more comfortable, efficient and healthy lifestyle.

For more information on Noritz America and the entire line of Noritz’s ENERGY STAR® tankless water heaters, please call (877) 986-6748 or visit our website at

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