The Water Heating Division of Rheem Manufacturing Company is introducing a new line of power-vented residential gas water heaters that incorporate the exclusive Guardian System^™ technology for flammable vapor ignition resistance (FVIR). The line was designed to meet Phase 2 of the American National Standards Institute Standard (ANSI) governing FVIR water heaters, effective January 1, 2006.

The new Rheem FVIR Power Vent line enhances safety and increases installation flexibility, giving contractor-installers greater assurance, more options and improved installation flexibility. The new features include: — more models, including 40- and 50-gallon short models in addition to Rheem’s tall power-vent models;
— a vent-run capability that is 37% longer than Rheem’s previous power-vent models, making it possible to vent horizontally or vertically up to 100 feet with two-inch or three-inch PVC, ABS or CPVC vent pipe;
— a new quiet blower;
— electronic ignition and controls that are easy to access and make diagnosing operating conditions a snap.
“Our 2006 line of power-vent gas water heaters makes safety and customer comfort top priorities,” says Rheem Water Heating vice president of marketing David R. Martin. “Rheem’s superior safety design gives the contractor-installer added confidence, while our technological advances provide more options and simpler installation.”  

New flammable vapor sensor: The new Rheem power-vent water heaters meet the ANSI safety standard through “exclusive engineering,” according to Martin. Power-vented models were a special challenge for the FVIR design, because of their use of electronic ignition (spark or hot surface), rather than the standing pilot used by traditional water heaters.

As such, power-vent heaters have the potential to collect flammable vapors in the combustion chamber prior to the ignition cycle. This vapor buildup can lead to a hard ignition and potential flashback. To address this concern, Rheem’s design incorporates a “flammable vapor detection sensor” as the centerpiece of its new FVIR Power Vent line.

“Rheem’s sensor provides a protective control system that disables the water heater in the presence of flammable vapor accumulation,” Martin explains. “The unique sensor will detect the vapors and shift the control system into a protective lockout mode before ignition can occur.”

Unique Guardian System: In addition to the vapor-detection sensor, the new FVIR Power Vent line will feature Rheem’s proprietary Guardian System technology to prevent flammable vapor ignition. First unveiled by Rheem Water Heating in July 2003, the Guardian System was specifically developed to meet and exceed ANSI Z21.10.1-2001, or Phase 1 of the then-new ANSI Standard governing FVIR water heaters. Phase 2 of FVIR compliance, ANSI Z21.10.1-2004, affects 30-, 40-, and 50-gallon, power-vented water heaters.

The final phase, covering all remaining residential products, will become effective on January 1, 2007. When fully implemented, all new residential gas water heaters (with inputs less than 75,000 BTU per hour) will have to meet the standard. Pre-existing water heaters are not affected and may remain in operation.

(Note: ANSI is a private, nonprofit organization that administers and coordinates the U.S. voluntary standardization and conformity assessment system.)

Background on the ANSI Standard: The ANSI FVIR Standard was established to reduce the chance of household fires and burns resulting from the improper storage and use of gasoline and other flammable liquids near residential, tank-type gas water heaters. When volatile liquids are used or spilled near a non-FVIR, gas-burning appliance, their vapors – which can travel readily and undetected – can ignite, causing fires and injuries.

The ANSI FVIR Standard requires that all new residential gas water heaters be designed to prevent flammable vapors outside the device from igniting. All residential gas water heaters that meet the ANSI Standard share a number of features: