Bradford White Defender FVIR

[Terry]

for Atmospheric (conventionally)
vented water heaters

During normal operation, air for combustion is drawn into the water heater through the opening in the jacket. This air travels down and around the combustion chamber and enters through holes in the very bottom of the corrosion-resistant combustion chamber. The air then travels up through the oriented flame arrestor plate louvers, where the velocity of the air is increased and its direction altered. The air then mixes in a normal manner with the supplied gas and is efficiently combusted, producing very low NOx emissions. In the case where trace amounts of flammable vapors are present in the air flowing into the combustion chamber, the burner or pilot flame harmlessly ignites the vapors. If flammable vapors are in sufficient quantity to prevent normal combustion the burner and pilot flame is shut down. Should the flammable vapors continue to the burner, the flame arrestor plate prevents the flames from traveling backwards and igniting vapors outside of the combustion chamber. The calibrated, multipurpose thermal switch recognizes this and shuts down the pilot and main burner. This switch also deactivates the burner and pilot in the unlikely event of restricted airflow caused by severe lint, dust or oil accumulation on the arrestor plate.
Bradford White web site

http://www.bradfordwhite.com/defender.asp#

[Cass]

It is fairly simple...the flame arrestor plate louvers act just like a mantel on a Coleman lamp where the gasses burn only on one side of it never passing through it...this is why the vapors never ignite the source of the vapors causing a fire...

Thanks, Terry!!!

[hj]

Another reason the mantles work is that combustion CANNOT occur unless there is oxygen/air present and the mantle flame keeps it out of the interior of the mantle. Popular Science has an article about the difference in combustion between a bubble filled with hydrogen and one filled with a hydrogen/oxygen mixture. The first one is a "pop" and the second a "BANG". The idea was to show the difference between a controlled flame in an LPG burner and an explosion of a house filled with propane.

[master plumber mark]

The Bradford white and Rheem have the best
FVIR systems available...

About two years ago I did have to take a bradford White out due to a quirkey down draft in the chimmney that was putting out the piolit light..in the garage....
I Had to install a Rheem and the problem went away...for good and it made me wonder
about downdrafts in to these FVIR systems...


I have been looking for a decent pic of a cross section of the Rheem FVIR, just to compare them.....cause it seemed to me at that time that the Rheems design held up better in that situation

.http://images.google.com/imgres?imgu...US281%26sa%3DN


I repaired a Whirlpool FVIR last week and noticed
when the furnace came on and started to run that their
was a slight back draft down through into the heat chamber..

it made me wonder if wether part of their problem is any
possibility of a back draft down into the heat chamber
tripping the high limit fuse....
with such a small air intake screen, if their is any back draft at all while the unit is burning, it would be like snuffing out a candle....or pushing down or warping the flame

either way its still a piece of junk.....

[SewerRatz]

I ran into a water heater that had the issue of the pilot going out randomly. So of course first thing I did was change the thermal couple. While lighting the heater the furnace kicked on and the pilot went out while I was holding down the pilot bitten and I got hit with a face full of exhaust from the furnace. The home owner stated this problem just started a couple weeks ago. So I busted out my trusty sewer camera and shot it up the flu pipe into the chimney, and found a huge birds nest with a couple dead birds stuck in the chimney. Once I cleared the nest out problem was solved. Now when I run into pilot issues the first thing I do is light up a smoke capsule and fire up the furnace to make sure I am not getting any back draft.

[Ian Gills]

I've got one of those and it's the second best bit of plumbing equipment in my house...

[Redwood]

I've got one of those and it's the second best bit of plumbing equipment in my house...

I think you are sadly mistaken...

[Ian Gills]

Come on Redwood. We all know what the best bit of plumbing equipment in my house is. She sits upstairs, all white in her porcelain glory.

Number 3 incidentally is the Redwood, outdoor faucet lawnmower bumper...