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Flame Arrester (FIVR): Water Heaters

Modern gas water heaters have a Flame Arrestor (FVIR) to help prevent the ignition of flammable gas vapors that may be in the air from your water heater. Flame arresters, or flame safety valves (FSVs), are one safety device found on water heaters and other appliances regulated by Title 10 (Energy Conservation) and Title 17 (Standards for General-Use Appliances) of the Code of Federal Regulations (CFR). Flame arresters also significantly reduce the risk of explosion caused by venting flammable gasoline or natural gas from leaking underground storage tanks. Flame arresters are not required on electric water heaters.

CAUTION! Flammable gas vapors may be ignited by the pilot light resulting in property damage, serious injury, or death. Flame arresters may not be sufficient to prevent a fire caused by back-drafting from the water heater into the flammable vapors. Flame arresters are not explosion-proof and will not reduce the risk of damage caused by an explosion.

Flame Arrester (FIVR): Gas Appliances

A flame arrester prevents combustion products generated in the combustion chamber from passing out of the appliance through the draft hood opening and instead forces these products to exhaust through vent pipes or chimneys. Flame arresters also help protect appliances against exposure to windblown sparks, glowing embers, oil fires, or similar potentially hazardous situations that can cause ignition when exposed to flames or high heat. Flame arresters (FIVR) are required on most gas appliances. Flame arresters must be used with all vented (Type B, BW, and VP) home heating equipment if the appliance is placed in or near a fireplace or other area where combustible vapors may be present; Flame arresters are also required for commercial (nonresidential) installations of residential appliances. Flame arrester requirements vary by state and region.

Flame Arrester (FIVR): Appliances That Use Combustion

A Flame Arrestor, or Flame Safety Valve (FSV), can help prevent flames from escaping through the draft hood opening of an appliance, which could pose a fire hazard. The Flame Arrestor acts like a one-way valve that lets combustion gases escape through the draft hood and up the vent pipe but prevents them from traveling back down into the combustion chamber where they could ignite and cause a fire in your home. Flame Arrestors must be present on appliances which use natural gas, propane, oil, or other similar fuels where combustion takes place inside of a closed space. Flame arresters also reduce the risk of explosion caused by venting flammable gasoline or natural gas from leaking underground storage tanks. Flame arrester requirements vary by state and region.

How To Install a Flame Arrestor Arrester

Your local codes will determine if you have to have a Flame Arrestor installed on your gas appliance. so then you need to get the Flame Arrestor installed. Here are some quick Flame Arrester installation steps to follow:

1) Shut off Gas Supply

2) Ensure the gas shut-off valve is CLOSED before proceeding with Flame Arrestor installation. Turn on the pilot light, let it run for about 10 minutes. This will ensure all excess gas has burned off. Then turn the water heater off and wait another 5 minutes to allow any remaining gas to vent out of the lines into the atmosphere.

3) Disconnect the flexible connector at end of the gas line that supplies your appliance (usually a knob or lever close to the appliance).

4) Remove old Flame Arrestor from appliance if present, by unscrewing Flame Arrestor, usually an arrowhead-shaped metal piece with a slot for a screwdriver. If Flame Arrestor is not present, then move on to step #5.

5) Install new Flame Arrestor as follows: Thread Flame Arrester into gas line as far as necessary to allow the Flame Arrester’s tab(s) to be within 1/4″ of end of either pipe, making sure Flame Arrester is fully seated and secure. A new Flame Arrester must be installed so that at least one and no more than two tabs are exposed between the appliances piping and the wall or floor surface. The Flame Arrestors handle should be pointed in the direction of the appliance’s pilot light (not down towards you).

6) When Flame Arrestor has been properly installed, open your gas supply line to Flame Arrestor.

7) Turn on Flame Arrester’s gas supply. You should hear a hissing sound coming from Flame Arrester’s handle letting you know it is working properly.

8) Light appliance pilot light to test Flame Arrester. If Flame Arrestor does not operate properly, shut off the gas supply again and recheck the installation of Flame Arrestor before turning the gas supply back on.

9) Once Flame Arrestor has been installed properly, turn your furnace or water heater back on so that appliance can run through its start-up cycle without any problems before restoring your home to its normal heating/hot water operation.

How To Test If My Water Heater Flame Arrestor Is Working Properly?

If Flame Arrester has been installed properly (see steps above), it should be tested periodically to ensure proper operation. Flame Arrester tests must be performed when the appliance is not running. Flame Arrestor will not operate if it becomes clogged, restricted, or partially blocked. Gas supply to Flame Arrestor MUST BE OFF for Flame Arrestor tests! If you suspect that Flame Arrester needs cleaning or servicing, remove the gas supply line from Flame Arrester and use a non-flammable substance such as water or soap suds through the hose attached to your gas supply as an initial test of Flame Arrester’s ability to pass fluids before proceeding with any further testing. This will prevent unnecessary service calls from being placed to your contractor if Flame Arrester is working properly.

1) Turn off the gas supply and light appliance’s pilot light as per the instructions above.

2) In a safe location away from Flame Arrestor, turn on the service valve (usually at front of the unit or where pipes come out of the ground).

3) Using soap suds or water through the Flame Arrestors hose (following initial test noted in paragraph 2), you should see bubbles forming and rising up through Flame Arrester’s handle and/or bubble rising through fluid coming out of handle depending on which type Flame Arrestor you have installed. If no bubbles form, Flame Arrester may be restricted with rust or other debris and must be inspected by a plumber or Flame Arrestor company representative. If bubbles form then stop, Flame Arrester is working properly.

How Do I Maintain My Flame Arrestors?

Once Flame Arrestors are installed and tested per above, they should be monitored periodically to ensure that they remain operable. Periodic monitoring shall include visual inspection of Flame Arrester’s handle to make sure it does not become restricted or clogged, as well as making sure Flame Arrester remains securely fastened to piping with no loose connection points where gasses may escape. Flame Arrestor must pass a bubble test outlined in paragraph 3 above during any maintenance tests performed on Flame Arrester. If repairs or cleaning are necessary due to restricted airflow issues, the gas supply MUST BE OFF to Flame Arrestor during repairs. Flame Arrestor service companies will provide Flame Arrestors for cleaning or repair, however, if you are not comfortable doing any necessary repairs to Flame Arrester, your local plumber should be able to complete the work.

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