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How to clean burner and combustion parts
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FVIR troubleshooting guide
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FAQ Rheem FVIR


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Three Different things: The FV sensor, the Rheem FVIR system TRD, the combustion chamber thermal device

If FV sensor on front of some heaters is tripped, the pilot light will not light
If TRD or Rheem's FVIR system is tripped, the pilot will light, but flutters out when gas valve is moved to operation for lack of air.
If combustion chamber thermal device is tripped, the pilot will not light becausethe the wires going to thermipile are switched off.

FV sensor mounted on outside of gas water heater is first layer of protection:

The FV sensor is different than FVIR flammable vapor ignition system.
The FV sensor is located on front of some water heaters. The sensor will trip if it senses gasoline vapors in the air, and shuts off power to gas valve, which shuts off gas to pilot and burner. It responds to gasoline vapors but does not respond to other types of flammable vapors.

While the FV sensor is located on front of some heaters, the FVIR system is located inside all brands of residential-grade gas water heaters 30-40-50-55 gallon tanks, and responds to all sources of high-heat events caused by flammable vapor ignition. Each water heater manufacturer can have a different design. The Rheem design includes a TRD glass vial.

The FV sensor is important since research shows that gasoline is the most common cause of fire or explosion caused by water heater.
FV sensor is a small 2-wire device located inside a plastic box to keep it dry and clean... if the sensor gets wet, is blocked, or has been covered with dust, leaves, water etc, it will not function.
The sensor must have continuity, so that a small current of electricity coming from thermopile can pass through the sensor and travel to gas control valve. 
The FV sensor is easily tested using multimeter and easily replaced by plugging new one into terminal slots.

Buy:
Flammable sensor kit
Resource:
How FV sensor works
How to test FV sensor
Rheem TRD Rheem FVIR flammable vapor ignition resistance system has a TRD/ thermal device located inside the combustion chamber
The water heater has a glass vial located in combustion chamber just above the air intake that breaks when sudden high-heat event exceeds parameter.

The very high temps caused by vapor ignition can cause the Rheem TRD ( a glass vial) to break nearly instantly and then a cover located under combustion chamber snaps closed over air intake.
This fast-acting system prevents vapor ignition from accelerating back out of heater and into room, helping to prevent explosion, and you need to install a new TRD.
Small or trace vapors will generally just burn up inside chamber without issue.

Rheem FVIR system trips because.
1. Ignition of flammable fuel such as gasoline or paint thinner can cause TRD glass vial to break.
2. Water heater dropped, or impact from car, earthquake etc.

If TRD is tripped, the pilot will light, but flutters out when gas valve is moved to operation.
Buy:
Rheem TRD/ thermal device

Resource:
Verify activated TRD pdf
Other causes of tripped TRD might include the following, but remember, the combustion chamber has a separate, slower-acting, thermal sensor that will trip off at lower temperature.
3. Overheat inside combustion chamber can break TRD glass vial.
4. Insufficient air intake or venting will overheat combustion chamber.
5. Vent pipe blocked, too many elbows in vent, dusty atmospheres, deterioration of part(s) caused by exposure to trace amount of chemical in air, such as pool chemicals, bleach etc.
6. Heater is undersized and runs constantly, causing condensation inside vent pipe that drips acidic water back onto burner and parts, causing deterioration, rust ect that slows burning. The flame becomes lazy yellow instead of crisp blue, slowing the exit of combustion by-product which overheats combustion chamber.

NOTE:
The combustion chamber has a seperate thermal sensor wired in series with the thermopile.
The thermopile sits in the pilot flame and generates small current that is used to power circuit board inside gas valve.

If combustion chamber gets too hot, then the thermal sensor will trip off, and cut off current generated by thermopile, with result that gas valve receives no current and shuts off gas going to pilot light and to burner, and issues error code.

Because the thermal sensor trips at lower temperature than TRD, the thermal sensor should respond to reasons 3-6 before the TRD trips.

Rheem FVIR Rheem FVIR or TRD uses glass vial
When water heater experiences FV flammable vapor event, the glass vial breaks, causing spring door located underneath the combustion chamber to snap closed cutting off air to combustion.

On Rheem/Ruud/Richmond etc, if glass vial breaks, you need a new part. Or, in case water heater is still under warranty, return heater to place of purchase for exchange if covered by warranty.
Typically, a warranty covers workmanship and not exposure to chemicals, flammable vapors, or bad installation.
Cause for FV event must be resolved before putting heater back into service.

FV water heaters evolve.Information given here can be different than your specific model
Broken TRD TRD glass vial is broken
What to look for on Rheem, Ruud, Richmond, GE heaters
Verify TRD is activated (broken)

Larger image
FVIR shuts off air supply

When glass vial breaks, the air is shut off to combustion chamber

The pilot will light, but flutters out when gas valve is moved to operation.

Solutions
Rheem TRD Solution 1: Order part online:
Rheem, Richmond, GE use TRD
Buy:
Rheem TRD/ thermal device
Resource:
Verify activated TRD pdf
Telephone Rheem Solution 2: Call Rheem or manufacturer: Check warranty, part availability, etc
Rheem, Richmond, Ruud, GE water heater: Gather information from label on side of tank, then contact Rheem and ask for glass vial, and other affected parts.

Read product manual for advisories about warranty.
Other brands: Call Manufacturer and ask for replacement parts and repair steps, and read manual for advisories.
Rheem warranty and extended warranty are pro-rated and say: 'the limit of liability is reached when the repairs/replacement equal the replacement cost of 'like and kind' equipment during the term of the agreement.
Return water heater
Solution 3: Return water heater to box store where purchased:
If you bought GE water heater at Home Depot, they will exchange for new heater


Solution 4: Replace heater
Rheem, Richmond, Ruud, GE water heater must be replaced unless Rheem / GE can ship glass vial.
Other brands water heater also require replacement.
Install new heater and follow prevention steps below.

How to install gas water heater
How to recycle old water heater
Which is best gas water heater

Flame arrestor screen located under glass vial
Before repairs are made
Clean flame arrestor so air can enter combustion chamber.
Use air compressor and duster.
Clean air intake located on side -or- located bottom of heater. How to clean air intake
If air intake is located on bottom of water heater, then water heater has 3 legs, and screen on bottom of tank is could be difficult to clean without removing burner.
Clean burner and clean combustion chamber. How to clean combustion chamber
Remove all flammables and household chemicals from area.
Move water heater out of dusty, dirty environment, and set 18" off floor
Inspect vent pipe and check draft. Vent test

Off-code repair

How to repair TRD
How to repair Rheem FVIR: If you cannot buy the glass vile that holds spring loaded door. You can by-pass device by removing burner assembly and using needle nose pliers. Reach in and bend metal bracket that held glass vile. Bend it so it holds open spring loaded combustion air door.
Next clean out the air intake, clean flame arrestor screen that filters incoming air, and follow prevention shown below. FVIR/TRD water heaters need plenty of clean air, and proper venting.
Your heater should now stay lit.
Solution 5: Repair work-around using ordinary fuse or nail
 Warning:  NOT code
Don't do this.
Insert cartridge type fuse (short variety) to replace glass vial


This is not a game.New heater costs a few hundred dollars. Hospitals, lost wages, lost careers, funerals, burned-down homes cost more.
I personally knew two fellows who were killed while laying floor tile in Chicago in 1978. They were using the old petroleum-based floor adhesive (now outlawed). Water heater ignited floor adhesive and conflagration killed both young men.
Recently, the local Lowes manager told me he had a friend who lost both legs. The fellow smelled gas. Instead of leaving the building and calling gas company, he removed front panel off water heater. The explosion and fire caused  life-altering injuries. His action by-passed the FVIR safety feature by removing front cover.
Gas control thermostat

How to access FVIR/TRD
Take photos of everything for easy re-assembly.
1) Remove wires as needed from Gas control valve and ECO located on combustion door
2) Disconnect Thermocouple, Manifold tube, and Pilot tube from bottom of Gas control. Notice these connections are not overtightened and do not require pipe sealant.
3) Gas controls vary. Manifold and pilot tubes on LP gas heater are reverse thread. Some thermocouples are reverse thread.
4) Burner door is held with 2-4 screws and may require replaceable gasket or sealant. Be careful with gasket so it can be reused.
Gas water heater burner assembly5) Pull out burner assembly. It will fit under or into a slot.
6) Reassemble after repair. Do not over tighten connections. Thermocouple is usually finger-tight + 1/4 turn.
7) Use soapy water and check manifold and pilot tube connections for gas leak.
DO NOT remove or loosen the combustion door without turning off gas.
Larger image
Product manual has diagrams and advisories
How to remove burner
Example combustion cover removal for Bradford White
Troubleshoot gas water heater

FV systems vary by brand
Information given here can be different from your specific model
Rheem Ruud Richmond GE
Worst choice for DIY repair:
Air intake located on side, must remove combustion door and burner to access, requires TRD part and installation inside combustion chamber..
Uses TRD glass vial trigger for overheating event
Arrestor screen located under combustion burner
Locate arrestor screen by removing burner
Clean arrestor screen with compressed air after removing burner. Company may send glass vial.
Reset thermal reset on front of unit
New gas valve may be needed
Rheem Does NOT post service manuals but might supply resources
AO Smith-
American-State-GSW-Lochinvar Craftmaster-Reliance-Kenmore-Whirlpool Best Choice in my opinion: Air intake on bottom
Arrestor screen stops acceleration of flames into room
Arrestor screen located under combustion burner
Locate arrestor screen on bottom of water heater
Set water heater on bricks
Clean arrestor screen with feather duster/ compressed air on bottom of heater
Reset thermal reset on front of unit
New gas valve may be needed
AOS Posts service manuals
Water heater service manuals
Troubleshoot flammable vapor
Troubleshoot AO Smith FVIR
Bradford White
-Boch-
Good choice/ remove combustion door for access
Air intake on side
Arrestor screen stops acceleration of flames into room
Arrestor screen located under combustion burner
Locate arrestor screen by removing burner
Clean arrestor screen with compressed air after removing burner
Reset thermal reset on front of unit
New gas valve may be needed
BW Posts service manuals
Troubleshoot Bradford White FVIR

What is FVIR  system: Flammable vapor ignition retardation system

When water heater ignites, the heat caused by fire starts to move air upward. This action draws fresh air up from air intake located under combustion chamber. The fresh air on Rheem water heaters enters from louvers located on side of tank near bottom.
In the case of power-vent water heaters, the blower motor draws fresh air into combustion chamber. With atmospherically-vented water heaters, where there is no draft inducing blower on top of unit, the metal vent pipe running up to the roof will create a natural draft upwards, just like a fireplace chimney naturally drafts upwards.
The vent pipe to outdoors creates natural draft upward that pulls fresh air into combustion chamber.

If fresh air entering combustion chamber contains flammable vapors such as gasoline, then water heater burner ignites the gasoline vapor.
If unchecked, the ignition of gasoline vapor inside water heater will spread back out into surrounding room causing flashover or explosion that can kill you and burn down house.
With FVIR water heaters, this flashover event is retarded or stopped. So when vapor ignites inside combustion chamber, the FV system senses very high heat and immediately shuts off air supply to combustion chamber.
This prevents flashover or explosion inside room.
Insurance company property and casualty losses prompted FV safety mandate.
Each water heater manufacturer is responsible for developing FVIR system.
Rheem developed system with glass vial that breaks in event of FV event.  Water heaters rated over 65,000 BTU do not have FV system. Tankless water heaters do not have FV system. Space heater, open fireplace, gas logs etc do not have flammable protection and each item listed above can ignite vapors and kill you if precautions are not taken.

Resettable TCO on front of combustion chamber. The TCO or thermal cut off responds to overheating inside the combustion chamber, and trips when temperature exceeds set point. This causes gas valve thermostat to shut off gas supply to burner.  Troubleshoot TCO
Gas water heater burnerSymptoms of tripped FVIR
1) On Rheem, Ruud, Richmond, GE heaters, look for signs of shattered glass on combustion floor.

2) Symptoms by type of gas control: With Robert-Shaw and White Rodgers gas control valve: If pilot light stays on without problems as long as gas valve is in PILOT position, but you then turn to ON position and main burner flutters and disappears within 30 seconds then good chance TRD is tripped.'
With digital-type Honeywell gas control and White Rodgers Intellivent gas controls, there are wires connecting combustion chamber and gas control that will shut off gas to burner and pilot. Pilot will not light. Burner will not light.

3) Caution: Same symptoms can also be bad gas control, low gas pressure, or clogged air intake.
Inspect if air shut-off baffle is tripped upward. Inspect for broken glass. Clean air intake. Avoid dusty atmospheres. If water heater brand is not shown on this page, consult manual for FV information.
Troubleshoot flammable vapor

4) If pilot will NOT light, and there is NO gas available, then ECO can be tripped. Check manual for ECO. Some ECO/TCOs are small button located on front of combustion chamber: this configuration is re-settable after overheating problem is repaired (clean combustion parts and air intake). Some ECOs are located inside gas control thermostat. ECO inside gas control is single-use, and gas control valve must be replaced. Consult manual. Follow maintenance schedule shown in manual for cleaning combustion parts. Test ECO

5) If pilot will not stay lit, then thermocouple might be bad. Test thermocouple.
Read: pilot will not stay lit

Soot on gas burner
Soot on burner and/or top of water heater indicate insufficient air supply. This causes heat build-up and can trip FVIR. Flame should be clear blue. Yellow flame indicates insufficient air.
Soot on water heater
-Clean air intake
-Clean combustion parts and chamber
-Check gas pressure
-Inspect/ repair vent
How to solder copper pipe
1) Do not store gasoline in open container.
Dusty environments
2) Avoid dusty atmospheres and give water heater adequate fresh air supply
How to prevent FVIR problems: (and ECO failure and other general water heater problems)
Caused by overheating inside combustion chamber
ADEQUATE FRESH CLEAN AIR
1) Do not store gasoline or flammables near water heater. Keep gasoline, kerosene in closed containers.
2) Avoid dusty atmospheres and give water heater adequate fresh air supply
3) Turn off water heater when using oil-paints, varnish, spray propellants, shellac, WD-40, thinners, lacquers, hair spray, gasoline, solvents, flammable cleaners, contact cement. Read product label to identify flammables.
4) Install water heater 18" off floor since gasoline vapors gather close to floor. Other flammable vapors do not gather close to floor.
5) Read product labels for flammability and advisories
6) Avoid storing or using chemicals in same room
7) Craft sprays and home project materials are flammable. Read labels
8) Read manual and follow yearly maintenance schedule for cleaning air intake and combustion parts.
9) Make sure vent pipes are working and that combustion parts and top of water heater are not sooty.
10) Don't drop water heater

Remove flammables away from water heater

Be cautious
Explosion inside your home wastes precious fuel, and could burn down neighbor's garage.
Buy:
Gas safety cans at Amazon

5) Read label for flammable warnings

5) Read product labels for flammable warning: shellac, Kilz, lacquer, varnish, craft spray, floor paint, spray paint, solvents, accelerants, cleaners, etc
FVIR mandates were passed to reduce insurance casualty and property losses.

Many household appliances can cause flashover and explosion of hydrocarbon fuels
Fireplace
Tankless water heater
Hybrid electric water heater
Oven
Stove
Space heater
Gas logs
Faulty wiring

Tank-type gas water heaters are located in garages and storerooms where flammable vapor storage is probably more likely to happen. People are more likely to clean a paint brush using gasoline while in a garage, rather than in the kitchen or family room.
gas control knob
3) Turn off water heater burner and pilot when using flammables
Raise water heater 18" off floor
4) Set water heater 18" off ground

6) Clean air intake regularly
FVIR cleaning
Test water heater vent pipe 7) Check if flue has proper draft by lighting match

See if smoke drafts immediately upward.
The smoke should not linger. It should draw upwards quickly.
If vent does not have draft or if furnace vent is blowing out of water heater vent each time furnace turns on, then vent pipes must be repaired.

All gas appliances must vent out of house to avoid CO poisoning.
Read checking the draft


Larger image

Power vent models
FVIR troubleshoot for Intellivent gas control valve
Resettable FVIR
Clear flammable vapors from area
Turn off power to water heater for 10 seconds
Within 10 seconds of restoring power, press both temperature adjust buttons simultaneously (blue and red triangles) until the green vacation LED begins to blink.
When Vacation begins to blink, release temperature adjust buttons
Again, within 10 seconds, press both temperature adjust buttons simultaneously until the vacation LED is on steady without blinking ( 5 second delay)
Release temperature adjust buttons, the microprocessor will clear FV lockout and normal operation will resume

AO Smith Effex water heater has resettable FVIR system
Same steps shown above are entered in control box located near top of heater.
Most water heaters need to be replaced 2012, but the manufacturers are working toward resettable FVIR.
And manufacturers have moved to conditional limited warranties that might require professional installation and yearly maintenance. Read the manual and specification sheet BEFORE buying. Call the manufacturer.
Troubleshoot gas control valve thermostats
Water heater gas control valve
Troubleshoot by type of GAS control valve

Troubleshoot by type of gas control valve

Remove gas valve
14 things needed for gas water heater & .pdf resources
What you need for operation of gas water heater.
General troubleshoot
1) Basic parts and operation
2) Adequate incoming air supply ... issues: closed doors, tightly insulated house, very hot attic.
3) Adequate air supply getting to burner... issues: dirty vent screen, dirty environment, maintenance.
4) Thermal cutoff  ... TCO ... issues: failed part, maintenance, vent.

5) Flammable vapor lockout .... issues: exposure to vapors, bad FV sensor, failed FV system,
6) Fuel supply to gas valve thermostat ... natural gas and propane are different ... issues: wrong gas, low pressure, moisture in pipe, undersized gas meter, supply line too small for BTU rating.
7) Gas valve thermostat regulates fuel supply ... issues: not enough gas, failed thermostat, failed gas control valve.

8) Fuel supply from thermostat to burner ... issues: maintenance, thermocouple-thermopile, gas control valve.
9) Clean and replace burner ... issue: periodic maintenance requires burner inspection, cleaning, and possible replacement

10) Functioning thermopile-thermocouple-pilot light ... issues: misalignment, failure of part.
11) Ignition of fuel supply by pilot light or hot surface igniter ... issues: pilot light, piezo igniter, electrode.

12) Power vent water heater troubleshoot ... issues: pressure switch, blower, blower sequence from gas control, outlet polarity
13) Venting combustion byproduct .... issues: vent in disrepair, other vents in house drawing air

14) Misc troubleshoot manuals

How to flush gas water heater
Solar water heater
9+ ways to save with water heater

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How to wire off-peak water heater

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