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How to troubleshoot gas water heater

SEARCH this page using Ctrl+F for browser Find feature
Newer version of this page
FVIR Lockout varies by brand, and model, but causes for FV trip are same/similar for all brands.
Push in TCO located on front of combustion chamber    See image
1) Keep air intake screen, or flame arrestor screen clean.  Dust and dirt can clog screen. Use feather duster, used compressed air. Install heater in clean environment free from dust and chemicals. Laundry room is not good location for FV water heater.
When arrestor screen is clogged, air flow slows down. Same amount of gas is being burned but heat is retained inside combustion chamber instead of venting up flue. The overheating trips FV system.
Solution for FV lockout event varies by brand and model, and by gas control valve. Try cleaning arrestor screen first. Push in TCO reset on front of combustion chamber.
Gas control valve may need to be replaced. FV sensor may need to be replaced. Part replacement depends on model and brand, since FV systems are changing rapidly last few years.
    2) Keep combustion parts and chamber clean. Lazy yellow flame, instead of clear blue flame, and sooting indicate incomplete combustion. Explosive gas can accumulate. Can trip FVIR.
    3) To prevent FV lockout: And combustion problems: Perform maintenance shown in product manual, and keep air intake clean, and avoid flammable vapors.
close up water heater air intake
Rheem-Ruud-Richmond-GE AO Smith-
American-State-Craftmaster-Reliance-Kenmore-Whirlpool
Bradford White-Boch-Lochinvar
Air intake on side. But arrestor screen located inside.
Uses TRD glass vial trigger for overheating event
Arrestor screen located under combustion burner. Read
Locate arrestor screen by removing burner
Clean arrestor screen with compressed air after removing burner. Look for broken glass.
Company may send glass vial replacement. Read more
Reset TCO thermal reset on front of unit
Rheem Does NOT post service manuals
Similar service manuals posted with gas control valves lower on this page
How to repair Rheem FVIR
Buy:
Rheem water heaters at Amazon
FV sensor kit
FV sensor kit
Best Choice in my opinion
Air intake and arrestor screen are same and located on bottom. See image
Arrestor screen stops acceleration of flames into room
Arrestor screen located under combustion burner on bottom of water heater
Set 3-legged water heater on bricks for ez access to arrestor screen
Clean arrestor screen with feather duster/ compressed air
Do not need to remove combustion parts to clean screen
Reset TCO thermal reset on front of unit
Clean screen and reset TCO will usually restore FV lockout
Service manuals are posted on AOS website
Service manuals also posted with g
as control valves lower on this page
Buy:
AO Smith water heaters at Amazon
Reliance gas water heaters
50 gallon high efficiency
Air intake on side. Arrestor screen located inside. Image
Arrestor screen stops acceleration of flames into room
Arrestor screen located under combustion burner. Read
Locate arrestor screen by removing burner
Clean arrestor screen with compressed air after removing burner, and this will usually restore FV lockout
Reset TCO thermal reset on front of unit
BW Posts service manuals
Service manuals are posted on BW website
Service manuals also posted with gas control valves lower on this page
Buy:
Bradford White water heaters at Amazon
Bradford White water heater parts
Buy:
Tent City USA tankless water heater/ off grid
Hybrid:
Heat pump water heaters at Amazon
GE 50 gallon hybrid heat pump at Amazon
Reliance 80 gallon heat pump at Amazon
Air tap: add to existing electric water heater at Amazon

FVIR resources that might help or not.

Read information above. It's probably best source of information;
Post question on pro water heater forum: Tank forum
Cleaning air intake might solve problem with Bradford White/ and AO Smith
Most of the service manuals give little or no information about solving FVIR. Call manufacturer.
How to repair Rheem FVIR
FVIR intellivent troubleshoot .pdf
Bradford White service manual .pdf
Bradford White 2 .pdf
General FVIR troubleshoot .pdf
AO Smith FVIR water heater .pdf
FVIR cleaning .pdf
2006 FVIR bulletin .pdf
American 2006 FVIR water heater .pdf
American powerflex water heater .pdf
AO Smith service handbook .pdf
Reliance water heater .pdf

How to troubleshoot gas water heater/ DIY Resources

SEARCH this page using Ctrl+F for browser Find feature
Install gas water heater
Turn off gas
When gas handle is perpendicular across gas line, then gas is OFF
When gas handle is is parallel with gas line, then gas is ON

Leave house if you smell gas.

Do not turn on light switch or touch any light switch or electrical device that might cause static spark

Water

Emergency steps for leaking water heater
Troubleshoot leaking water heater
Flooded water heater
Gas water heater parts
Basic parts
Larger image

Gas water heaters are not  standard today. Models vary. Manufacturers each have different design. Designs change frequently.
Honeywell gas control
Electronic controls have thermopile instead of thermocouple
Larger image

Mechanical control thermostats have thermocouple
Larger image
Replacement
How to replace water heater gas valve

Buy

Gas water heater thermostats Amazon
AO Smith gas valves at Amazon

Buy:
AO Smith gas water heater at Amazon
Bradford White gas water heater
Rheem gas water heater at Amazon

Prevent problems

Maintain water heater and it will last many years beyond warranty. Read manual and links below.
How to maintain water heater
    1)  Read about anode rods
    2)  Read about stray current corrosion
    3)  How to flush water heater
    4) Inspect for leaks
    5)  9 ways to save with water heater
    6) Water heater safety precautions
    7) Read manual and follow maintenance schedule and precautions

2012
Troubleshoot gas water heater starts here:
SEARCH this page using Ctrl+F for browser Find feature
Find current manuals at some seller's websites
Water heater manufacturers

***Tank Forum***

Links below contain valuable resources.
Also Recommend Tank professional water heater forum   Not affiliated with this site.
Sign up, Post a question, or Use search feature at tank to find information available nowhere else.
Example topics:
Burner will not stay lit
Burner flame is yellow
Bad thermocouple on new Rheem water heater
 
Thermocouple Test and replacement
How to test water heater thermocouple
How to replace thermocouple 2/ Utube
How to replace thermocouple pdf
How to replace thermocouple/ forum
Test thermocouple
Test thermocouple and thermopile
Buy:
Thermocouples at Amazon
Thermocouple adapters

How to install thermocouple when burner must be removed

Thermostat
Thermostat calibration, means tank temperature matchs thermostat setting. Adjust temp, replace gas control.
How to adjust thermostat temperature
Replace thermostat on gas water heater

Troubleshoot water heater gas control valve More resources below
How to test White Rodgers gas valve p14
How to test Honeywell Icon gas valve p23
How to test Robertshaw gas valve p14
Troubleshoot Intellivent gas valve
Burner goes out when knob turned to ON

Replace gas control
Gas control is the thermostat
How to replace gas control
Replace gas control
How to replace water heater gas valve
How to replace Honeywell gas control
Bradford White gas control replacement
LP heaters have left-hand threads
Calibrate gas control valve
Gas valve manufacturers
Operation and safety
Safety magnet

ECO
Test ECO on Robertshaw- White Rodgers
ECO on Robershaw,White Rodgers, Honeywell pg 17

FVIR
How to repair Rheem TRD
FVIR troubleshoot
FVIR troubleshoot for intellivent
2006 FVIR bulletin
How to repair Rheem FVIR
Intellivent FVIR troubleshoot and reset

Power vent
Venting
Read product manual for venting specifications
Minimum vent distance from window
Power vent tables
Typical power vent manual
Typical power vent manual2
Gas venting specs
Water heater vent test/ pdf
Avoid corrosive atmospheres
Conditions where outdoor air supply is needed
Square footage per BTU
Remove burner & replace thermocouple thermopile
Gas water heater burner assembly
How to Remove burner & replace thermocouple thermopile

General troubleshoot and service manuals:

Troubleshoot gas water heater
Troubleshoot gas water heater2
Test if thermal device needs replacement/ pdf
Reliance 2006 troubleshoot handbook/ pdf
AO-Smith-service-manual/ pdf
AO Smith service manual
AO Smith service manuals
AO Smith 2006 service handbook
AO Smith Technical bulletins
Bradford White Service Manual/ pdf
Bradford White technical bulletins
American troubleshooting guides
State service manual
Icon gas valve error codes
Dampered water heater troubleshoot/ pdf
Hot surface igniter troubleshoot/ pdf
American gas water heater service manual
Intellivent service manual
Whirlpool Energy Smart Gas Service/ pdf
Polaris troubleshoot and install manual
Rheem service bulletin
Rheem-Ruud 2011 parts list/ pdf
Rheem parts 2010
Rheem-Ruud 2009 parts by model number
Rheem 2009 parts list

Pipe size and capacity
Pipe size & BTU chart
Pipe capacity
Gas pipe capacity .pdf

Safety
Water heater safety precautions before starting
Water heater precautions/ pdf
Gas-water-heater-Safety-Precautions
Gas valve safety
Thermal expansion
Insulation blanket

Convert to different gas
Convert water heater to different gas
Convert to different gas 2
How to replace gas control valve
Cautions for convert to different gas

 Igniter
How to test piezo igniter
How to check the igniter
Electronic spark troubleshoot
Troubleshoot hot surface ignition
Hot surface igniter troubleshoot
Power vent hot surface ignition
pilot light troubleshoot
Larger image
Pilot light troubleshoot:
Troubleshoot gas water heater pilot light
Clean the air intake, and get more fresh air to unit.
Use mirror to look upward, and to one side, through sight glass to see that pilot flame is clear blue. Push in TCO located on front of combustion chamber.
Test thermocouple
How to light gas water heater
Pilot light goes out
Burner goes out when control knob turned to ON
Pilot light will not stay lit/ pdf
Pilot outage/ pdf
Attic Ventilation and Pilot Outage
Pilot outage and negative pressure
Pilot light maintenance/ pdf
Ventilating tight-house/ pdf
Pilot light troubleshoot
when thermostat set lower
Pilot problem or ECO or gas control?
Wind blows out pilot light
Pilot light or thermocouple?
Negative pressure blows out pilot


blower Blower
Power vent troubleshoot
Troubleshoot hot surface ignition
How to check blower motor
Check blower motor
Buy: Water heater blowers at Amazon

Pressure switch
Test pressure switch
Air pressure switch testing
Intellivent wiring
Pressure switch replacement
Check pressure switch

General how-to
Find age of water heater
How to replace drain valve
Leaking water heater
How to read the gas meter
Clean sediment out of tank and periodic flushing
How to install electric water heater
Thermal expansion tank
Noisy-gas-water-heater

Common water heater problems:
Tank water heater forum
Low hot water pressure
Stacking
Crossover
Flooded water heater
Vent Gas Odor
Lack of air supply
  -Clean air intake screen, open window
  Ventilating tight-house/ pdf
Improper vent
  -Read product manual for vent requirement
Downdraft
Poor combustion
  -Clean combustion parts, service unit
Typical manuals
Typical power vent manual
Sample Rheem Gas water heater manual
AO smith Service manuals
Whirlpool manuals
Cleaning water heater
Example: cleaning combustion chamber
Example: how to clean combustion chamber
Clean sediment out of water heater
Troubleshoot Rheem Tankless

Troubleshoot Bosch tankless
Troubleshoot electric water heater
Post questions on professional water heater forum

Troubleshoot by gas control valve

Back to 10 things for troubleshooting water heater
Icon gas valve
For atmospheric vent models
Range Low 55° - very hot 160°
Average bath 110°F, typical water heater temp 120°
ECO limit 199° F, ECO trips, gas valve fails
TP release water at 170°
All calibrations are approximate
Severe scalding risk over 135°
To reset gas control, rotate dial to OFF, wait 10 minutes for gas to clear. Then relight.
Buy
Reliance/ Honeywell gas control
American / Honeywell gas control
Kenmore water heater gas valve
Craftmaster/ Whirlpool
Bradford White
AO Smith

Honeywell gas control at Amazon
American / Honeywell gas control at Amazon
Honeywell gas valve for propane
Honeywell natural gas valve
Reliance NG at Amazon
Reliance LP at Amazon
Kenmore water heater gas valve
Gas water heater timer fits this valve
Replacement instructions
How to test & replace Honeywell/ pdf
WT8840 replacement manual
How to replace Honeywell gas control valve

Resources WV8840/ WT8840:
Typical installation manual
Typical installation manual/ low NOx
Adjust temp on Honeywell gas valve
Error codes WV8840 series
Error codes WV8840 series
Error codes WT8840
AO Smith service handbook
Service handbook
State Error code/ troubleshoot/ service manual/ FVIR
Bradford White service manual
Error light blinking 4 times
How to light water heater
How to light water heater/ pdf
How to light Whirlpool energy smart

WT8840 product overview models
WT8840 gas valve manual and troubleshoot

How to replace gas control valves
How to test gas control valve

How to install gas water heater

For power vent and flue dampered models
Range Low 90° - very hot 160°
Average bath 110°F, typical water heater temp 120°
ECO limit 199°F, ECO trips, gas valve fails
Average bath 110°F
ECO limit 199°F
TP release water  at 170°
Buy
Example Honeywell gas control valve at Amazon
Reliance NG at Amazon
Replacement instructions
How to replace water heater gas valve

Resources:
Flue dampered service manual/ atmospheric
Flue dampered/general install and troubleshoot
Dampered troubleshoot codes
Dampered error codes
Dampered error codes
Induced draft troubleshoot codes
Example dampered install manual2

Example power vent install manual
Example power vent install manual
Example power direct vent install manual
Adjust temperature/ error codes on Honeywell
How to light Honeywell gas valve
Error codes and troubleshoot chart
Error codes
Error codes
Icon gas valve error codes

AO Smith service handbook
Bradford White power vent service manual 1
Bradford White power-vent service manual 2
Bradford power-direct-vent service manual
Condensing power vent service manual
Test gas control/ from BW service manual
Sequence of operation
How to clean burner

Safety
Water heater safety precautions
Water heater precautions/ pdf
Gas-water-heater-Safety-Precautions
Gas valve safety
Thermal expansion
Insulation blanket

For power vent models
Range Low 80° to Hot 150°
Error C flashes at 160°
Buy
Buy Intellivent gas control at Amazon
White Rodgers/ Rheem Intellivent gas control
AO Smith intellivent
AO Smith Intellivent at Amazon
AO Smith White Rodgers at Amazon

Replacement instructions
How to replace water heater gas valve

Resources:
How to light water heater
Typical installation manual
Sample installation manual
Example install manual
Ultra low nox power vent manual
Error codes and adjust temp on Intelli-vent
AO Smith Intellivent troubleshoot and FV test
Troubleshoot Intellivent/ pdf
FVIR intellivent troubleshoot .pdf
Intellivent service manual TC-048 R6
Sequence of operation and service brief
Intellivent wiring
Power direct vent troubleshoot
Status codes and troubleshoot/ condensing
How to reset intellivent
For resetting controller:
Method A... After the unit has been off for at least a minute, plug it in, turn on switch; within a few seconds, depress both arrow buttons on controller, and hold them until the left light begins to blink.  Release them, and within a few seconds, push those arrow buttons in the following sequence:  L/R/L/L/R/L/R/R.  This should reset the controller.
Method B... after FV event on AO Smith
1. Turn off power to water heater for 10 seconds.
2. Restore power to water heater.
3. Within 10 seconds of restoring power, press the two temperature adjust buttons simultaneously until the left (green) “Vacation” LED begins to blink (approx. 5 second delay). Once the Vacation LED begins to blink, release both buttons.
4. Again, within 10 seconds, press both temperature adjust buttons simultaneously until
Vacation LED is on steady (approx. 5 second delay).
5. Release two buttons, the  microcomputer will clear the FVS lock-out and normal
operation will then be restored.
White Rogers thermostat
Resources:
Troubleshooting/ pdf

How to light gas water heater
How to replace water heater gas valve



gas valve setting
Buy
Gas control valve thermostats at Amazon
Gas water heater thermostats at Amazon
Rheem gas control valve at Amazon
Gas control valve at Amazon
Camco White Rodgers at Amazon
Replacement instructions
How to replace water heater gas valve
Resources:
Service manual
Service manual 2
Service manual 3
How to light water heater/pdf
General troubleshoot manual /pdf
White Rodgers gas control valve replacement pdf
Power vent water heater issues
Magnet testing
Test thermocouple
Gas valve testing
How to light gas water heater
White Rodgers NG replace, install, set temp
Honeywell Smart Valve AO Smith
Honeywell Smart Valve
Larger image

Resources:
Temperature settings and features
Smart valve error codes
Service manual
Install smart valve & troubleshoot
Robertshaw Natural gas control valve
Robertshaw Natural gas
Buy
RS Natural gas at Amazon
Camco RS at Amazon


Buy
Gas water heater thermostats at Amazon
Replacement instructions
How to replace water heater gas valve


Resources:
Robert Shaw models
Robert Shaw troubleshooting/ pdf
Unitrol troubleshoot/ pdf
General troubleshoot/ pdf
General troubleshoot manual /pdf
How to light water heater/pdf
Magnet testing
Test thermocouple
Gas valve testing
Recalibrate gas control/ pdf
How to light gas water heater
Adjust pilot on unitrol gas control valve
Atwood gas control valve

Atwood gas control valve

Fits all Atwood water heater that have a pilot light

Buy:
Atwood gas control valve at Amazon
Atwood parts at Amazon
Atwood water heaters and parts at Amazon
Resource:
How to replace gas control valve thermostat
Atwood water heater troubleshoot resources
Suburban water heater service manual

Kenmore with power anode rod
How to light Effex water heater
Effex service manual

Suburban water heater service manual

Whirlpool energy smart gas water heater manual
SIT gas control valve for water heater
SIT gas control valve for water heater
Larger image
How to light and set temperature SIT gas control

Robert shaw gas control valve
Robert Shaw 120Volt input gas control valve
Wiper Control and Gas Valve assembly
Triangle pointed upward is 120 degrees F
Replacement for Rheem power vent/ Buy
Rheem wiper SP20123A thermostat KIT
Wiper SP20123B valve/ no thermostat


Resources
Larger image
Error Codes and troubleshoot
Guardian power vent Robert Shaw error code
Rheem parts list
American power flex parts
General manual with lighting instructions
Replace water heater gas control and FV
Check pressure switch, blower, gas control
Sequence of operation
How to light water heater
To reset: turn the red control knob on and off 6 times within 30 seconds to reset the board.
Honeywell L4006 water heater controller
Honeywell immersion thermostat
12-277 volt AC SPST controller
12-48 volt DC
Add to any hot water tank
Surface mount or immersion into tank
Temperature range: 100-180°F
Water over 135° poses extreme danger of scalding.
Add mixing valve.

Buy<
Honeywell/ Rheem SP11798B
Honeywell L4006

Resources:
Add another thermostat to gas or electric water heater
Advantages-disadvantages mixing valve
Control recirculation pump using controller
L4006 manual
L4006 wiring illustration
Honeywell L8104 water heater controller
Gas water heater ECO

Gas water heater thermostats are usually single-use after ECO trips

Water heater Gas thermostat has Energy Cut Off
When ECO senses overheating inside tank, the ECO trips and shuts off gas.
If water heater burner or pilot has gas, then ECO is not tripped.
Gas valve must be replaced (except Intellivent which can be reset).
ECO must have continuity

Read more
Test ECO on Robertshaw- White Rodgers
Read about resetting intellivent

Buy
Gas water heater thermostats at Amazon

Power ventblower Blower
Buy blower:
Water heater blowers at Amazon

Resources:
Power vents:
Power vent water heater issues
Anode covered by power vent

Blower troubleshoot
Power vent troubleshoot
Troubleshoot hot surface ignition
How to check blower motor
Check blower motor

Pressure switch troubleshoot
Test pressure switch
Air pressure switch testing
Intellivent wiring
Pressure switch replacement
Check pressure switch



Larger image

Flame trap inspection
Clean air intake on AO Smith, State, American, Reliance, Whirlpool water heaters

Rheem, Richmond, Ruud, GE heaters require removal of combustion parts to clean arrestor screen inside unit.
Soot on gas burner
Soot implies dangerous situation
Gas may not be burring fully
See image on right

Soot on top of heater also implies danger.

Lighted inspection mirror
Buy:
Flame trap inspection mirror at Amazon

Flame should burn clear blue
Low gas pressure.
Dirty combustion parts.
Poor incoming air supply.
Inadequate venting.

This is dangerous because unburned gas can accumulate inside combustion chamber or inside the flue way. Causing ignition.
This situation will overheat combustion chamber and trip ECO, TCO and FV system, causing water heater to stop working.
Follow product manual for correct maintenance protocol

How to read gas meter

Definitions and formulas/ pdf
Pipe size BTU chart
Pipe capacity
Square footage per BTU
Pilot orifice
Pilot tube orifice
Clean with compressed air or carburetor cleaner
Standing pilot light maintenance
Burner brush

Burner brush
Buy:
Tube cleaners at Amazon
Burner brush tube cleaner at Amazon
Burner Tube Brush Cleaners at Amazon
Appliance cleaning brushes at Amazon
Straw cleaning brush
Clean water heater burner
Use wire brush to clean burner assembly and combustion chamber. When re-starting cold tank, expect condensation dripping until tank reaches temperature.
Burner cleaning /pdf
Example: how to clean combustion chamber
Clean water heater burner line
Expanded image
Buy:
Tube cleaners at Amazon
Gas water heater burner assembly
Water heater burner assembly with piezo igniter
How to clean burner
Larger image

How to remove burner
LP gas water heater burner
Burner for LP gas is made of cast iron because LP gas burns hotter.
Comparison NG-LP
Manifold tube and pilot tube are also made heavier to resist pressure & high heat of burning LP gas
Example shows rusty burner that has not been cleaned
Gas control valve for LP gas will accept left-hand threads for pilot and manifold tubes
Gas water heater burner
Larger image
NG gas burners are different than LP burners.
LP has more pressure and higher temp
Bradford White Piezo igniter
How to test piezo igniter
Bradford White gas water heater service manual
Gas water heater
Gas water heater
How to remove burner
Flame rod sensor
Location of flame sensor and igniter vary by model and brand of water heater.
Larger image
Hot surface igniter troubleshoot

Sand carbon deposits off igniter.
Avoid touching igniter

Larger image
Intellivent troubleshoot Manual
Power vent surface ignition
Tip of flame sensor must be directly in front of burner port.
Use a nickel to set 7/64 gap.
Natural gas flame sensor will be bent, while propane will be straight.
Gas burner without piezo igniter
Larger image
Burner flame is yellow
Gas control thermostatLarger image
White Rodgers gas control valve replacement pdf
ECO wires/ thermocouple/ manifold tube/ pilot tube/ piezo igniter
How to test water heater thermocouple
LP heaters have left-hand threads

How to install thermocouple when burner must be removed
Gas valves
Larger image
Don't over tighten gas line to control valve or damage to control valve can occur.
How to set temperature on gas valves
Remove gas valve
How to replace gas control
Replace gas control
Operation and safety
How to replace Honeywell gas control
Buy universal gas control wrench
Or make a wrench out of plywood
Whirlpool ECO thermal switch
Whirlpool resettable ECO/TCO thermal switch trips when combustion get too hot. Prevents overheating: Clean burner parts.
If pilot or burner is receiving any amount of gas, then ECO is not tripped
Test ECO
Rheem FV sensor at Amazon
FV sensor at Amazon

Replacement reset thermostat at Amazon
Gas water heater ECO Water heater Gas valve thermostat has Energy Cut Off
When ECO senses overheating inside tank, the ECO trips and shuts off gas.
If water heater burner or pilot has gas, then ECO is not tripped.
Gas valve must be replaced. Read more
How to replace gas control
Replace gas control
Test ECO on Robertshaw- White Rodgers Must have continuity

FVIR water heater:

How to repair Rheem FVIR
FVIR troubleshooting guide
Symptom of FV failure
'If pilot 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 99% chance TRD is tripped.' (On Rheem heaters, look for signs of shattered glass on combustion floor.)
Same symptoms can be bad gas control
Newer gas water heaters have flammable vapor sensor connected to gas control valve

SP20172 FV sensor reacts to gasoline vapors, shuts off gas control valve, and water heater will not work.
Pilot will not light .. replace sensor
Buy: flammable sensor kit


TRD or FVIR tripped
Rheem older water heaters use glass vial that may or may not be replacable
How to fix Rheem TRD
If system is tripped, the bulb glass is visible on floor of combustion chamber.
FVIR shut off
FV sensor, or FVIR, trips and shuts off gas & air supply to combustion chamber.

FV system: When water heater is exposed to flammable vapor, and the vapor ignites inside combustion chamber, the FV system immediately shuts off air supply to combustion and prevents a flashover or explosion inside the room.

Each water heater has a different design.
Call manufacturer for instructions for replacing or resetting FV.

FVIR troubleshoot guide
Rheem water heater parts list 2011
Rheem parts list 2010


   Read more2  Read more3
Raise water heater 18" off floor
Raise water heater 18" off floor to avoid flood damage and flammable vapors
Help prevent FVIR event by installing gas water heater at least 18" off the floor.

#1) Make sure there is adequate fresh air, and that air is clean and list free, and does not have trace chemicals.

#2) Always turn off gas to water heater when painting with oil-base paint or oil-base varnish, and when cleaning with solvent-based products, and when pouring gasoline etc.
For example when storing gasoline near water heater, the water heater should sit minimum 18" off floor, gasoline should be tightly capped, and do not pour gas to fill gas tank in same room as water heater.
Ventilate attic
Larger image              Read pdf
Attic ventilation is needed for gas water heater.
Increase ventilation to water heater
How to solder copper pipe

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
Dusty environments Avoid dusty environment that will clog air intake, cause unburned fuel, and create fire hazard
-Do not install cold water line above gas valve where condensation drips on valve.  
-Annually clean burner area with wire brush and vacuum cleaner. read1 read2
Troubleshoot and clean gas water heater

Remove chemicals from same room as water heater.
-Chemicals corrode water heater parts and vent pipe. 'Spray propellants, cleaning solvents, refrigerants, swimming pool chemicals, calcium and sodium chloride, household bleach, waxes and process chemicals are corrosive at very low levels with no odor." Read Bradford White Pdf pg2-8    Read Rheem pdf
Trace chemicals
Outlet polarity If gas valve is connected to electricity, the outlet polarity must be correct
Water heater must be grounded. Poor ground can prevent flame. GFCI circuit can cause short cycling. If outlet is not dedicated or has GFCI, other loads such as florescent lighting can cause short cycling.

Unplug cord. Test for continuity between ground prong on plug and manifold tube on gas valve.
Connect water heater to different outlet. Test outlet with circuit analyzer
Gas valves How to set temperature on gas valves
If you maintain the tank: keep chemicals out of same room, attach bare copper ground wire between hot and cold pipes, flush tank each 6 months, clean burner each year as shown in manual, read the manual entirely for specific information about your model, and inspect/replace anode rod every 2-3 years then basic 6-year tank can last much longer. 
Test water heater vent      How to test water heater vent.
Let main burner operate for 5 minutes.
Then put match near vent hood.
Smoke from match should get sucked into vent
Water heater vent test/ pdf
Checking the draft
Read more at Tank
Attach vent hood to water heater
Flue pipe safety
See larger

During typical water heater combustion, hydrogen content of fuel is burned and the result is hot gases. One of these hot gases is steam or water vapor. Adequate venting or air draw up vent is required so gases vent outside. 
When there is inadequate draw, the water vapor cools and condenses on inside wall of vent pipe. This condensation water is acidic (pH 3-5) and corrosive. It will corrode steel metals and other materials.
Improper venting causes water to drip down vent into combustion chamber of gas water heater. Parts inside combustion chamber rust. Holes develop in bottom of water heater. Inspect combustion chamber for rust and water.

If steel vent pipe is not venting, the vent pipe will rust and get holes, or joints will fall apart. This situation causes hot gases to enter home and poses serious risk of odorless CO poisoning.

Simple test for proper venting: Pipes are not rusted or covered with white condensate. No water on top of tank. Burner inspection does not show excessive rusting. Light match under vent pipe and see if smoke immediately draws upwards. If smoke does not draw, then call plumber.
Flue Pipe Safety
Read manual for flue pipe clearances so hot vent pipe does not touch or come near combustibles.
Rusted flue pipe -or-water on top of gas water heater could indicate serious problem.
Call a plumber if you are uncertain.
Check pipes and flexible connectors for leaks.

If water coming from flue pipe:
1. Vent cover could be missing > rain water entering flue (replace cover)

2. Flue pipe clogged with bird nest or come apart or damp from improper venting: danger of odorless Carbon Monoxide poisoning

Serious danger from CO poisoning, a plumber should be called if you are uncertain about vent pipe water leak
Read troubleshooting at forum
See u-tube video
Read about CO detector

Glass lined steel water heater
How to replace anode rod
Minimum distance of vent pipe from window     Minimum distance of vent pipe from window
Side-wall vent pipe must be 4 feet away from windows and doors. And 3 feet away from inside corners.
Larger image with more information
Power direct-vent clearances
Venting a gas water heater
Conditions where outdoor air supply is needed

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