Bradford White Defender FVIR System Water Heater Review

bradford white defender label The Bradford White Defender FVIR (Flammable Vapor Ignition Resistant) System is by far the best available on the market today. Other Manufacturers have struggled with design and reliability problems including one that resulted in a class action settlement. FVIR is a safety system for gas water heaters that prevent the water heater from becoming an ignition source for vapors from spilled flammable liquids. As of July 1, 2003, 30, 40, and 50-gallon, gas-fired water heaters built for sale in the United States were required to have FVIR protection with others phased in over time.

A simplified description of how FVIR Technology works is that older designs had an open combustion chamber where combustion air is drawn in at the base of the water heater. When a flammable liquid was spilled or used in the area of the water heater flammable vapors would accumulate along the floor and if the vapors reached the pilot or burner flame in the correct proportions they could ignite and burn back to the area where the flammable liquid was spilled or, being used, causing an explosion and or, fire. The FVIR technology encloses the combustion chamber of the water heater and draws the combustion air through a flame arresting device where it is used for the pilot and burner. There is also a device that senses if the flame is too tall or, overheating either from a lack of proper combustion air or, too much fuel caused by flammable vapors entering the unit. Improper flue venting may also affect the temperature in the burner area. In any case when an unsafe burner condition, or FVIR event is noted the sensor shuts off the gas supply to the burner and pilot flame preventing ignition of the flammable vapors.

Bradford White Defender FVIR Water Heater and Cut Away Drawing Showing Combustion Air Inlets on the side and the FVIR Burner

Bradford White Defender FVIR Water Heater and Cut Away Drawing Showing Combustion Air Inlets on the side and the FVIR Burner

Virtually every water heater manufacturer other than Bradford White has had problems in one form or another that result in their customers either having to face excessive maintenance and repair costs, unreliable operation, or even replacement of the water heater in some cases.

One manufacturer had a thermocouple with a thermal fuse built in that had a reverse thread. This thermocouple when tripped was required to be replaced and was unavailable except through the manufacturer requiring a wait for the replacement parts, and if you wanted it faster there was a substantial cost for expedited shipping. This resulted in a class action lawsuit and a fix involving replacement of the burner assembly to one which used a thermal device with a reset switch and a design change for the new production units.

Bradford White Thermal Reset Switch

Bradford White Thermal Reset Switch

Some of the manufacturers have the combustion air drawn in through a small screen on the bottom of the water heater only a small distance above the floor. This design has faced problems with the screen clogging with dust and lint causing a lack of proper combustion air and tripping the sensor. This problem was amplified by the fact that water heaters are typically installed in laundry areas, closets and basements which are typically high lint and dust areas and the fact that the screen is located under the unit near the center and is difficult to access to clean when the water heater is set in the code required pan.

Another manufacturer has the combustion air inlet on the side of the unit but it is low between the bottom of the water heater and the combustion chamber door this is only slightly better than the bottom of the unit in terms of getting it away from the high dust area at floor level.  It also requires replacement of the pilot assembly once the FVIR sensor has tripped.

Bradford White Defender FVIR burner diagram showing combustion air flow

Bradford White Defender FVIR burner diagram showing combustion air flow

Yet another manufacturer has a design which I consider to be second best as it has the combustion air inlet up on the sides which is good but does not have a reset for the FVIR sensor. Tripping of the FVIR sensor requires replacement of the pilot assembly. Fortunately for their customers the likelihood of dust and lint clogging the flame arrestor is greatly reduced by the height of the combustion air inlet and the pilot assembly is readily available.

Only the Bradford White Defender FVIR System brings all the right stuff to their design. They have the combustion air inlet high on the side of the unit where cleaner air is drawn into the unit keeping the flame arrestor from clogging with lint and dust. The design of the flame arrestor has larger openings that rely on velocities of the air flow and changes in direction to provide the flame arresting function giving less likelihood of lint and dust clogging over the screen design. A reset button is provided for the FVIR sensor so no parts replacement is required if there is an FVIR event. This combination of features makes Bradford White Defender FVIR Water Heaters my pick for the best FVIR water heaters. They are by far the lowest maintenance, highest in reliability, & lowest in repair frequency among the FVIR gas water heaters available. Whether or not you have hot water in the morning should be the last thing on your mind, yet sadly for many people, it is something they have to worry about.

Posted in Water Heater Reviews Tagged with: , , , , , ,
59 comments on “Bradford White Defender FVIR System Water Heater Review
  1. Buck says:

    BW MI 40T6FCX, wouldn’t stay lit. Got hoodwinked by big Houston “authorized” repair service, ARS, who replaced thermostat exactly like top left one on p. 19 of gas fired manual. Didn’t know about reset button until talking with BW rep on 6/3/13. Has been ongoing problem since replacement in 2/12. Curt at BW said check venting (all clear), propane pressure (fine), or clean vapor screen. please tell me how to do that. Do I disassemble whole heater since it’s on the bottom or what. Heater is on platform
    In a hall closet. BTW, I would gladly go back to old water heater, non-electronic, fire it up and let her rip. One I replaced lasted 25 years. This junk has been a pain since year two.

    • Redwood says:

      Hi Buck,

      Dust and lint buildup on the flame arrestor screen is a big problem with all FVIR water heaters. That said, the Bradford White design is the best of the bunch. Could you imagine a design that doesn’t have a thermal reset button but instead relies on a oil filled glass vial that breaks when the temperature in the burner chamber gets too high or, a design that draws the combustion air from under the unit rather than the side of the unit?

      When the flame arrestor which is a fine screen on the Bradford White FVIR water heaters becomes clogged with a buildup of lint, dust, and other fine debris, the burner flame starved for combustion air becomes larger, and triggers the thermal reset just like an FVIR event where additional fuel vapors are drawn into the unit. The screen does not allow flame to pass through so it prevents vapors in the room with the water heater from being ignited and as a safety shuts the unit down when they are detected.

      If your thermal reset switch is tripping without flammable vapors being drawn into the unit, you need to clean the ScreenLok® Flame Arrestor using stiff brush, compressed air and/or shop vacuum to remove any scale or, other debris accumulation. Using a soft brush, clear jacket openings of any dirt, dust, restrictions or other obstructions. requires cleaning. This said, the job entails disconnecting the gas supply to the pilot and main burner, removal of the sealed inner door, removal of the burner assembly, and cleaning the screen, which is a complex job involving gas connections and should be done by a qualified professional for safety reasons.

      The procedure is covered on page 36 of the service manual for this unit which I will e-mail you in the form of a PDF file.

      Hope this helps,

  2. sharon says:

    I turned off a Bradford defender water heater while the house was being renovated now when I try and light the pilot the LED indicator light does not come on at all. Any suggestions?

    • Redwood says:

      Hi Sharon,
      The full instructions for lighting your pilot light can be found on Page 19 of your manual that should be with the unit. If you don’t have the manual Click Here for a PDF of the Manual. Basically you have to open the outer door to the burner area to be able to see the pilot light through the glass window. Once the pilot has been lit you’ll have to hold the gas control button down after the pilot light is lit for some time before the LED starts blinking. Your water heater uses a Thermopile vs. the conventional Thermocouple for flame sensing, the Thermopile generates a voltage about five times higher than a conventional Thermocouple which is used to power the microprocessor in the ICON Gas Control Valve. It will take a minute or, two before it starts generating the required power so the pilot lighting button needs to be depressed until the LED comes on, this is noticeably longer than the conventional thermocouple would take.

      If you are following these instructions and continue to have a problem please write back or, you can call Bradford White at 800-531-2111 for Service under your Warranty.

      Hope this helps,

Leave a Reply

Your email address will not be published. Required fields are marked *


You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>