FVIR gas water heaters or flammable vapor ignition resistant water
heaters are designed to stop house fires caused by flammable vapors
that are ignited by a water heater pilot light or burner.
Vapors from gasoline, paint thinners, charcoal
lighter etc. that enter the combustion chamber
and are ignited can be contained and snuffed out
by shutting off the air flow, the gas supply to
pilot and burner, and/or contain by the spark
arrestor, depending on the brand of water heater.
Every manufacturer has a different design, and designs are
What they all do is contain flammable vapors inside the burner
compartment and shut down the gas to the pilot and burner.
Almost all brands have a flame arrestor located under the burner
in the bottom of the cabinet. The arrestor will allow air and vapors
in but stop a flash fire from exiting the compartment.
Some models have a door that will seal the vent/ spark arrestor
in case of a flash fire.
Different safety switches have been designed to shut the gas
off in the combustion chamber should a flash fire occur.
Standard non FVIR water heaters are no longer manufactured
Its estimated that water heaters cause 400 house fires a year with
an average of 5 deaths.
Electric and gas fired water heaters are all grouped together in these
The FVIR water heater industry is voluntary and was recommend by the
manufactures and related associations.
FVIR water heaters should save some homes and lives.
Water heater by their nature are installed in out of the way, dusty
areas such as carports, basements, and closets.
Most FVIR units have a fresh air vents with spark arrestors located
in the bottom of the unit.
When the burner/manifold fires to heat the water, it pulls air along
with dust and debris into this vent. When it becomes clogged the
new safety devices will shut the water heater down.
The manifold must be removed and compressed air used to clean
the air vent and spark arrestor properly. The average cost to have it
cleaned by a licensed professional is $120.00.
Some manufactures sell vacuum cleaner attachments to reach
under the water heater and vacuum the screen. This will help
if you keep the surrounding area clean and clean the screen regularity.
Once the spark arrestor becomes clogged the manifold must be
removed to clean it.
Before FVIR water heaters came on the scene, all gas water
heater parts were interchangeable. If you needed a gas valve
or thermocouple, just run down to the local hardware store
and pick up one for your gas type.
Their are many water heater companies that do not make their
parts available in local areas. Even services companies have a
problem getting parts for some models. The results are families
going days sometimes more than a week without hot water.
If your water heater shuts down because of a clogged filter/
spark arrestor or because of a heat flash from flammable vapors
you may have to replace the safety device that shut it down
and you may have to replace the gas valve or water heater.
FVIR gas water heaters have become expensive to buy and can be
very expensive to own, not to mention time consuming to
If you are in the market for a gas water heater, check for parts
availability in your area.
You could be without hot water for days if parts are unavailable.
You will probably need a service manual if you plan to repair
it yourself. It should be available as a free download from the
Search for customer reviews about the water heater and the
FVIR related pages