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to troubleshoot gas water heater SEARCH this page using Ctrl+F for browser Find feature |
| Basics | ||
| Emergency? Water leak, gas leak, vent leak, flood  |
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 Turn off gas When gas handle is perpendicular across gas line, then gas is OFF CO poisoning from gas appliance: headaches, lethargy, unconsciousness.Remove affected people to fresh air. Lay on side, never on back, call for emergency assistance, open windows, call plumber to inspect gas appliances Water Leak: water heater should have shut off located on cold water line: turn handle righty-tighty to shut off water, lefty-loosey to turn water on. Flood: never wade into water, stand on wet surface, or touch appliances including water heater until absolute certain electricity is OFF. Flooded gas water heater must be replaced. Gas valve that went under water is not functional, reliable or safe. Gas appliances are dangerous if not in correct working order. Risk of electrocution from wet floor or wet water heater: Power vent and flue damper vented heaters are plugged into 120 volt electricity. A GFCI is not used on this type h  eater
due to potential malfunction of heater, so these water heaters are
electrocution hazard when standing on bare floor, damp floor, soil
(earth), or leaning into grounded appliance such as washing machine,
dryer etc Stand on dry boards. Troubleshoot power vent water heater Resources Emergency steps for leaking water heater Troubleshoot leaking water heater Flooded water heater How to light gas water heater |
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| Not enough hot water? Water too cold? |
Step 1)
Open drain valve and check if water is hot inside the tank a) If water is hot, then plumbing is suspect Resources: Low hot water pressure Crossover Broken pipe or leaks running hot out of tank Hot water connected to toilet or outdoor spigot Mixing valve is broken Other valves not functioning Hot water runs out in 5 minutes: Recirculation system needed or not functioning |
b) IF water is not hot at
drain valve, then water
heater is suspect. Resources: How to light gas water heater Test gas valve thermostat Broken dip tube Undersized water heater Calculate first hour delivery Calculate recovery Other reasons are covered on this page |
| Water too hot? | Water
too hot? Troubleshoot gas control thermostat Stacking |
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| Common water heater problems | Common
water heater problems: Low hot water pressure Stacking Crossover Flooded water heater Leaking water heater |
General
how-to Find age of water heater How to replace drain valve 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 Tank water heater forum |
| New water heater? | How to install gas water heater Which is best gas water heater |
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| Solar | Heat
with solar Connect PV water heater / low voltage Connect PV water heater / high voltage |
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Prevent problems Maintain water heater to last years beyond warranty. 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) Repair water heater valves 7) Read manual and follow maintenance schedule |
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Resources: Definitions and formulas/ pdf Pipe size BTU chart Pipe capacity Square footage per BTU Gas pipe capacity .pdf |
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| Basic
parts For more complete list: basic-parts-for-gas-water-heater.html |
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Larger image Energy factor EF .675 - (.0015 x V volume in gallons) 40 gallon tank: .675 - (.0015 x 40) = 61.5% efficiency 38.5% of heat goes up flue pipe into atmosphere. |
Basic parts Gas water heaters are NOT 100% standardized. Models vary. Manufacturers offer different designs. Illustrations show atmospheric vent where natural updraft of air pulls toxic combustion by-product up flue pipe and into atmosphere. Parts not shown include: Electronic gas control valve, power vent, flue damper vent, FV sensor, flexible gas line, air intake, thermocouple, thermopile, pilot etc. Resources TP valve code Replace TP valve Repair water heater valves Remove short water heater nipple Broken dip tube Replace drain valve How much does it cost to run gas water heater Index of all plumbing links |
 Larger image |
 Electronic gas controls receive current from thermopile that powers circuit board that controls electromagnets and gives status codes used for troubleshooting Larger image |
Basic gas
valve thermostat parts Gas water heaters have a gas control valve with a probe that extends into water heater that responds to water temperature. Electronic gas valve and mechanical gas controls operate differently from each other to do same job. Replacement Troubleshoot gas control valve thermostat How to replace water heater gas valve How to light gas water heater Details about the honeywell gas control How water heater thermostats work 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 |
 Mechanical gas controls receive small current from thermocouple that controls electromagnets inside the valve. Larger image |
 Honeywell Electronic gas controls that are used on power vent, power direct vent and flue dampered heaters are powered by 120 volt or by 24 volt AC from a transformer. Some models and brands of heater have a small transformer that converts the 120 volt into 24 volt, and the gas valve is powered by 24 volt. While other heaters use 120 volt to power the gas valve and operation of heater. Buy Example Honeywell gas control valve at Amazon Reliance NG at Amazon |
The gas valves shown left and right are different from
gas valves shown above. All water heater gas valves control the gas supply and operation of the heater, but these gas valves are used for water heaters that plug into 120 volt outlet and have blower or damper assisted combustion. The 120 volt is used to power the gas valve ... plus power the blower or damper motor, and the electronic control system. Because the gas valve is powered by household electricity, the water heater does not have thermopile or thermocouple. Types of household water heaters |
 White Rodgers Intellivent Electronic gas controls are used on power vent, power direct vent heaters and are powered by 120 volt. 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 |
| 10 things needed for
gas water heater |
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What you need for operation of gas
water heater. This page contains information for each item with .pdf resources 1) Adequate incoming air supply ... issues: closed doors, tightly insulated house, very hot attic. 2) Adequate air supply getting to burner... issues: dirty vent screen, dirty environment, maintenance. 3) Thermal cutoff ... TCO ... issues: failed part, maintenance, vent. 4) Flammable vapor lockout .... issues: exposure to vapors, bad FV sensor, failed FViR system, 5) Fuel supply... natural gas and propane are different ... issues: wrong gas, low pressure, moisture in pipe. 6) Gas valve thermostat regulates fuels the thermal switch bad? For example TCO trips when combustion chamber is not hot. Temporarily jumper a wire across the two terminals and see if water heater functions. supply ... issues: not enough gas, failed thermostat, failed gas control valve. 7) Fuel supply to burner ... issues: maintenance, thermocouple-thermopile, gas control valve. 8) Functioning thermopile-thermocouple-pilot light ... issues: misalignment, failure of part. 9) Ignition of fuel supply by pilot light or hot surface igniter ... issues: pilot light, piezo igniter, electrode. 10) Power vent models ... issues: pressure switch, blower, blower sequence from gas control, polarity 11) Venting of combustion byproduct .... issues: vent in disrepair, other vents in house drawing air |
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| Troubleshoot starts here | ||
 Image of Bradford white air intake Buy: Bradford White water heaters |
Back to 10 things for troubleshooting water
heater 1) Incoming air supply Water heater must have enough air to support combustion. Well-insulated house or closed doors can prevent adequate air from reaching water heater. Very hot attic will cause oxygen molecules to spread too far apart to support combustion. AO Smith and 3-legged water heaters have air intake located on bottom of heater (install heater on 3 bricks to elevate space under heater), Bradford White (pictured) has air intake on side. Solution: Do not install gas water heater in small contained area, use louvered doors, do not pile belongings around water heater. Get fresh air to water heater and see if problem is resolved. |
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Air supply ..''gas
burning appliance requires the oxygen contained in 12.5 cubic feet of
air (at sea level) for every 1000 BTU of heat that is generated. If
your water heater has a BTU per hour input of 40,000 BTU then a minimum
of 500 (40 times 12.5) cubic feet of clean air must be available.This oxygen will mix with the gas for a clean, blue flame in the burner chamber and provide dilution air for flue by-products.'' ''Lack of Oxygen: If a sufficient supply of oxygen (air) is not available for combustion and dilution, the result will be: • Pilot outage, burner will not light or stay lit  •
Yellow burner flame, lazy yellow flame• Sooting water heater ... points to possible dangerous operation • Possible carbon monoxide • Smell of burnt gas, combustion odors in the room'' • Slow hot water recovery "1. Turn on every appliance and fan that exhausts air from the utility room and/or house. Make sure all windows and doors are closed, as well as chimney dampers. 2. Open a hot water faucet so that the main burner will ignite 3. Remove the outer door of the water heater – not the inner door 4. Looking through the viewport, monitor the flame characteristics for several minutes If the flame begins to “yellow” open a door or window, to the outdoors, to see if additional air corrects this back to blue (with red and yellow flicks). If it does, the room needs more air supply. Perform draft test at drafthood of water heater with match or smoke source to verify.'' 5. Do the vent draft test |
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 Corrosion of parts.Chemicals can damage burner parts Do not expose water heater to stored chemicals, swimming pool chemicals, laundry equipment 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." "Chemical vapor corrosion of the flue and vent system may occur if air for combustion contains certain chemical vapors. Spray can propellants, cleaning solvents, refrigerator and air conditioner refrigerants, swimming pool chemicals, calcium and sodium chloride, waxes, bleach and process chemicals are typical compounds which are potentially corrosive." Poor venting can damage parts 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. Avoid corrosive atmospheres |
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 AO Smith air intake on bottom of heater shown |
Back
to 10 things for troubleshooting water heater 2) Air supply getting to burner Air intake must be clean. If intake is blocked, the combustion flame is yellow and lazy instead of crisp and blue. Water heater might not stay lit. See manual for location of air intake. Do not install water heater in dusty environment. Avoid dusty environment that will clog air intake, cause unburned fuel, and create fire hazard. Some FV designs can trip if the air intake is clogged. |
 Dirty, dusty and chemical environments pose hazards for all gas appliances. Water heater air intake will clog, and shut down burner or cause FV lockout in some models. Whirlpool shown. |
 Larger image Location of AO Smith/ American/ Kenmore/Whirlpool 3-legged water heater with arrestor screen that will clog with dust amd cut off air. |
 Inspect and Clean air intake on AO Smith, State, American, Reliance, Whirlpool water heaters using feather duster or compressed air. Buy: Flame trap inspection mirror at Amazon |
Bradford White, Rheem,
Richmond, Ruud, GE heaters require removal of combustion parts to clean
arrestor screen located inside unit. Remove combustion parts for maintenance. Image of Bradford white air intake Buy: Flame trap inspection mirror at Amazon |
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Flame should burn clear blue Lazy yellow flame indicates one or more of following: -Poor incoming air supply. -Inadequate venting. Vent clogged or obstructed. Troubleshoot vent -Dirty combustion parts. Clean combustion chamber -Low gas pressure. High gas pressure How to check gas pressure -Loose manifold tube between gas valve and burner -Wrong orifice -Bad gas control valve Troubleshoot by type of gas control |
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 Very hot attic causes oxygen molecules to spread too far apart to support pilot light. Increase ventilation to water heater Resource: Attic ventilation/ pilot outage pdf |
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Back
to 10 things for troubleshooting water heater 3)
Thermal cutoff ... TCO is
a resettable thermal switch located
on the front of combustion chamber door.The TCO is integral with the thermocouple or thermopile depending on type of water heater and gas control valve. When temperature inside combustion chamber exceeds thermal rating, the TCO will turn off circuit from thermocouple or thermopile, causing the main electromagnet inside gas control to stop receiving electric current, which de-energizes the main electromagnet and shuts off gas to pilot and burner. TCO prevents overheating of flue pipe, and water inside tank, and tripped ECO (energy cut off) in the gas control valve. Temperature cutoff points for TCO range from 160°C to 200°C depending on model. The pilot has to be relit after the TCO cools down below 120° F The TCO has 2 functions: 1) Respond to flammable vapor ignition and 2) Respond to high temperatures caused by inadequate air supply Push inward to reset, or replace part as needed. Tripped TCO causes a complete shut down of gas control valve, and no gas reaches the combustion chamber. If there is a pilot light burning, or flutter of gas on the burner, the TCO is not tripped, then gas control valve is suspect. Causes of tripped TCO are dirty combustion parts, clogged vent... these things cause overheated combustion chamber. Solution: Push in button to reset, replace TCO, clean burner parts, check vent is drafting air. Is the thermal switch bad? For example TCO trips when combustion chamber is not hot. Test the TCO thermal switch. Temporarily jumper a wire across the two terminals and see if water heater functions. Buy: Thermal reset See basic water heater parts |
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 FV sensor mounted on outside of
gas water heater is first layer of protection:The FV sensor flammable vapor sensor is different than FVIR system flammable vapor ignition system. FVIR systems vary by
manufacturer or brand.
FV sensor is same across all brands. The FV sensor is located on front of many water heaters near the bottom. The sensor will trip if it senses gasoline vapors in the air. The FV sensor does not respond to other types of flammable vapors. FVIR system is located inside the water heater and responds to all sources of flammable vapor ignition, and in some models, responds to overheating events caused by miscalibrated thermostat or failed TCO etc. The FV sensor is important since research shows that gasoline is the most common cause of fire or explosion caused by water heater. Note: FV Sensor does not prevent the ignition of flammable vapors, the FVIR System is designed to reduce the risk of flammable vapor-related fires.  FV sensor is located inside a plastic case to keep it
dry and clean...
if the sensor is blocked, or has been covered with dust, leaves, water
etc, it will not function. The sensor must have continuity, so a small current of electricity can pass through the sensor that signals to gas control valve that no gasoline vapor is detected. The FV sensor is easily tested using multimeter and easily replaced by plugging new one into terminal slots.  Buy:Flammable sensor kit Multimeters at Amazon Electric testers at Amazon Resource: How FV sensor works How to test FV sensor |
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FVIR Rheem thermal device: Buy: Rheem TRD/ thermal device Resource: Verify activated TRD pdf How to repair Rheem TRD Troubleshoot Bradford White FVIR Troubleshoot AO Smith FVIR |
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 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 etc, 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 or other gas appliance. Buy: Water heater stand 4) Flammable vapor Lockout varies by brand, year and model. Resource: Verify activated TRD pdf How to repair Rheem TRD Troubleshoot Bradford White FVIR Troubleshoot AO Smith FVIR When lighting water heater, if you have NO gas or pilot light but burner goes out when knob turned to ON ... then FVIR system is suspect. Some water heaters have FV system that is tripped by variety of different problems including flammable vapors, or installation in dusty dirty environment. a) Push in TCO located on front of combustion chamber See #3 above for TCO. Gas control valve may need to be replaced. FV sensor may need to be replaced. Part replacement depends on model and brand. c) Keep combustion parts and combustion chamber clean. Lazy yellow flame, instead of clear blue flame, and sooting on the burner surface indicate incomplete combustion. Explosive gas can accumulate. Can trip FVIR. d) To prevent FVIR lockout and combustion problems: Perform maintenance shown in product manual, and keep air intake clean, allow plenty of fresh air, avoid dusty-dirty environments, and avoid flammable vapors. |
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| FV
lockout Rheem-Ruud-Richmond-GE Air intake on side. Some models use TRD glass vial trigger for overheating event. See image Arrestor screen located under combustion burner. Locate arrestor screen by removing burner Clean arrestor screen with compressed air after removing burner. Look for broken glass. Company might send glass vial replacement. Reset TCO thermal reset on front of unit. Rheem does not post service manuals Buy: Rheem water heaters at Amazon FV sensor kit Resources/ across all brands: How to repair Rheem FVIR FVIR intellivent troubleshoot .pdf Bradford White service manual .pdf Bradford White 2 .pdf General FVIR troubleshoot .pdf |
FV
lockout AO Smith-American-State-
Craftmaster-Reliance-Kenmore-Whirlpool Air intake and arrestor screen are same and located under combustion burner on bottom of water heater. Best location for ez cleaning. See image No need to remove combustion parts to clean screen. Clean arrestor screen with feather duster/ compressed air. Arrestor screen stops acceleration of flames into room. Set 3-legged water heater on bricks for ez access to arrestor screen. Reset TCO thermal reset on front of unit Clean screen and reset TCO will usually restore FV lockout AO Smith posts service manuals. Service manuals also posted with gas control valves lower on this page Buy: AO Smith water heaters at Amazon Reliance gas water heaters 50 gallon high efficiency |
Bradford
White-Boch-Lochinvar Air intake on side. ScreenLok flame arrestor screen located inside. Image Arrestor screen stops acceleration of flames into room. Arrestor screen located under combustion burner. Locate arrestor screen by removing burner. If dust and dirt collects on arrestor screen over timer, clean with wire brush and compressed air after removing burner, and this will usually restore FV lockout. TCO thermal reset on front of unit will cut off gas to pilot and gas control valve. Reset. Bradford Posts service manuals. Service manuals also posted here and also with gas control valves lower on this page Buy: Bradford White water heaters at Amazon Bradford White water heater parts FVIR Resources How ScreenLok flame arrestor works Bradford white FV troubleshoot Bradford white power vent FV troubleshoot |
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 Buy: Flexible gas line Keep ends of pipe connections clean when installing or repairing gas supply or water heater. Do let stray pieces of teflon tape get inside pipe... wrap tape one second thread from end and not at end. Install sediment trap and loop on flexible gas line to keep out moisture and debris. Use black pipe and yellow flexible gas line. Do not use galvanized pipe or flakes of galvanized will chip off and get into gas control. Do not use copper pipe unless approved locally.. |
Back
to 10 things for troubleshooting water heater 5) Fuel supply Natural gas and propane gas are different. Water heaters are purchased by type of gas used. Propane requires greater air supply ratio than natural gas. Propane has higher ignition temperature and burns hotter. The gas control valves are different with different threads for each type of gas. The burner and internal parts are different. Natural gas is lighter than air and rises. Propane is heavier than air and falls to low spot. Do not install propane appliances below ground level where gas leak can accumulate in basement. Water heaters are rated by BTU, or the amount of gas they burn. Gas lines and gas meters are rated by BTU for the amount of gas they can supply. Higher elevations consume more gas to achieve same BTU output. New appliance, or too many appliances can affect amount of gas. If overall consumption of BTU is greater than supply, then water heater will not function. Larger gas meter, or gas line may be needed. Look at labels on each appliance. Call gas supplier. Do not use copper pipe or galvanized pipe. Use only black pipe or yellow-colored flexible gas line. Check local codes for approved pipe that is non-reactive to the type of gas being used. Dirt, debris, moisture, galvanized flakes etc from wrong pipe or dirty pipes will get into the gas control valve and cause it to malfunction. yellow is international color code for gas line. Acceptable to reuse flex line when installing new appliance. |
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 Use approved yellow gas line and flexible gas connections:  Buy: Flexible gas line Buy: Pipe threading machine |
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 Larger image natural gas burner Another images NG gas burners are different than LP burners. Connections to natural gas control valve are right handed. |
Back
to 10 things for troubleshooting water heater 7) Fuel supply to burner The gas control valve lets gas flow into the combustion chamber through the pilot tube and manifold tube. The pilot tube has an orifice that restricts gas flow for the type of gas and the amount of pilot flame needed. The manifold tube is larger and sends gas to the burner in the amount to meet BTU rating of water heater. The gas control valve must match the pilot and burner. |
 Propane gas burner made of cast iron, shows manifold and pilot tubes, and thermocouple. Connections to gas control valve are left handed. LP has more pressure and higher temp |
 Image shows natural gas burner assembly with piezo igniter, pilot tube, manifold tube, and thermocouple. Some gas water heaters have modular burner assembly that is replaced whole, instead of individual parts. Buy: AO Smith burner assembly Rheem burner assembly Bradford White burner |
 Expanded image Burners and burner assemblies can be cleaned serviced. -Maintenance manuals suggest annually cleaning burner area with wire brush and vacuum cleaner. Buy: Tube cleaners at Amazon |
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 |
 Soot implies unburned gas: dangerous situation Gas may not be burning fully: lazy yellow flame indicates poor incoming air supply, dirty combustion parts, high or low gas pressure, bad gas control valve, loose manifold tube, wrong orifice, inadequate venting of combustion byproduct. Symptoms can include soot on top of heater, soot on burner, pilot outage, smell of burnt gas.; This condition must be addressed immediately, and can release toxic, odorless carbon monoxide.  Soot on top of heater implies danger of improper vent and backdraft #11 venting Improper vent can blow out pilot light. |
Flame should burn clear blue Low gas pressure. Dirty combustion parts. Poor incoming air supply. Inadequate venting. Bad gas control valve. Loose connection between manifold/ burner tube and burner 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. Resource: How to test gas pressure on water heater |
 Use wire brush to clean burner assembly and combustion chamber. When re-starting cold tank, expect possible condensation dripping until tank reaches temperature. This is the only time water should be apparent inside the combustion area of water heater, otherwise #11 bad vent or leaking water heater is suspect. Cleaning water heater Burner cleaning /pdf Example: how to clean combustion chamber Example: cleaning combustion chamber Example: how to clean combustion chamber Clean sediment out of water heater Clean combustion chamber Effex water heater Leaking water heater |
 Larger image |
Back
to 10 things for troubleshooting water heater 8) Thermocouple- thermopile, pilot light Pilot light heats the thermocouple or thermopile, producing small millivoltage of electricity that travels to the gas control valve along the copper pilot tube. If the pilot light goes out, the lack of electric current shuts down the gas control valve and pilot light needs to be lit again. Older model gas water heaters required a long match and patience to relight pilot, while more recent water heaters are required to have sealed combustion chamber and use a piezo igniter to light pilot. Thermocouple and thermopile are different. Thermopile is basically several thermocouples combined and produces more current than thermocouple. Thermocouples are used with older-style mechanical gas control valves that have a round dial on front. Thermopiles produce enough current to power small circuit board and are used with modern electronic gas control valves. |
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 With
the mechanical gas control valve thermostats,
the pilot flame heats the end of a thermocouple. A
thermocouple is
2 dissimilar  metals
joined together that produce small current when
heated. The small electric current travels from the thermocouple
though a hollow tube that contains a wire inside. The thermocouple tube
screws into to bottom of the control valve, where it
connects to an electromagnet. If the pilot light is ON and thermocouple is sitting in the pilot flame, and the thermocouple is working and making electrical connection to the gas control, then the electromagnet is energized. The electromagnet holds open the safety valve as long as the pilot flame is heating the thermocouple. If the pilot light is out, then the electromagnet closes the safety valve, and no gas can enter gas control. When pilot is re-lit, the magnet makes audible sound that can be detected when troubleshooting. If the pilot flame is extinguished, it can take up to 180 seconds for the thermocouple to cool sufficiently for the electromagnet to de-energize and close the safety valve. The safety valve determines if gas can flow into gas control. If safety valve is open, then gas control operates normally, and releases gas continually to the pilot light through the pilot gas regulator valve, and releases gas to burner through the main regulator valve when thermostat probe detects water temperature is below set point as selected on dial located on front of gas control.  With the electronic gas control valve, the pilot flame heats a thermopile instead of thermocouple. The thermopile works on same principle as thermocouple, except is larger and creates more current than thermocouple, enough current to power a circuit board inside the gas control valve. Unlike thermocouple, the current from thermopile travels to gas control valve through two wires that connect to front of gas control. The circuit board controls a series of self-check routines, error compilations of water heater operation, etc and uses electromagnets to control flow of gas that enters the gas control, and gas going to pilot and burner. See basic gas water heater parts If no current is produced by thermocouple or thermopile, then gas to the valve is shut off until pilot is re-lit or defective thermocouple or thermopile replaced. The temperature-reading thermostat on a gas valve is located inside a copper tube that protrudes into tank and reads water temperature. When water temperature drops below selected thermostat setting, then the gas valve releases gas through the manifold tube and into the burner located in combustion chamber. How to adjust temperature Gas flows out of the burner where pilot light ignites gas. If burner is dirty, sooted or obstructed, the gas may not light immediately, resulting in unburned gas building up until it reaches the pilot flame causing explosion hazard. Sooted and dirty burner and yellow flame indicate this problem. After cleaning the burner and the combustion chamber, the gas should burn blue with bits of red and yellow. Clean burner |
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Look upward, and to one side, through sight glass to see that pilot flame is lit and clear blue color. Causes for pilot outage: Backdraft from shared vent and wind coming down the flue can blow out the pilot. see section 11 for venting. Dirty combustion parts and need for maintenance can also cause outage. see section 7. Bad thermopile or thermocouple. Misaligned thermocouple can also cause outage. Modern water heaters have solved the misalignment problem with fixed positioning and 1-piece replacement for combustion parts. see section 7. Bad gas control valve can cause pilot outage. see section 6. |
Pilot
light troubleshoot: Clean the air intake, and get more fresh air to unit. Push in TCO located on front of combustion chamber. Pilot troubleshoot resources 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 Pilot problem or ECO or gas control? Wind blows out pilot light Pilot light or thermocouple? Negative pressure blows out pilot |
 Pilot tube orifice Clean with compressed air or carburetor cleaner Do not rub with rag, or tube can clog Pilot troubleshoot resources con't Standing pilot light maintenance Attic Ventilation and Pilot Outage Pilot outage and negative pressure Pilot light maintenance/ pdf Ventilating tight-house/ pdf Pilot light troubleshoot |
 Buy: Rheem Pilot assembly AO Smith Pilot Reliance Pilot Kenmore Pilot Bradford White Pilot |
 Gas water heater How to remove burner |
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| Avoid
Corrosive environments Exposure to corrosive environments such as pool chemicals, process chemicals, bleach can damage burner parts. Air is drawn into water heater, and if air contains trace amounts of chemical, or chemicals are burned in the flame, this will damage water heaters over time, and shorten life of water heater. Remove chemicals from same room as water heater. -Chemicals that will corrode water heater parts and vent pipe include: 'Spray propellants, cleaning solvents, refrigerants, swimming pool chemicals, calcium and sodium chloride, household bleach, waxes and process chemicals ... all these chemicals are corrosive at very low levels with no odor." Read Bradford White Pdf pg2-8 Read Rheem pdf Avoid corrosive atmospheres |
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| Piezo
igniter Today's water heaters have igniter to send spark to pilot light to start flame. Older water heaters have open combustion chamber and pilot was lit with a match ... the piezo igniter helps prevent explosion into someone's face, or ignition of flammable vapors in the room caused by open flame. The igniter is part of the FV flammable vapor prevention system where the combustion chamber is sealed so flames cannot easily travel from inside combustion chamber out into surrounding room. 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 |
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 Buy: Thermocouples at Amazon Thermocouple adapters Thermocouple Test and replacement How to test water heater thermocouple How to replace thermocouple pdf How to replace thermocouple/ forum Test thermocouple Test thermocouple and thermopile |
Thermocouple/ thermopile Remove burner & replace thermocouple thermopile  How to Remove burner & replace thermocouple thermopile |
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 |
| Back
to 10 things for troubleshooting water heater 9) Ignition of fuel supply by pilot light or hot surface igniter ... issues: pilot light, |
Hot surface igniter | |
 Location of flame sensor and igniter vary by model and brand of water heater. Sand carbon deposits off igniter. Avoid touching igniter Larger image Hot surface igniter troubleshoot Hot surface ignition basics Troubleshoot hot surface ignition Hot surface igniter troubleshoot Power vent hot 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. Larger image Intellivent troubleshoot Manual Power vent surface ignition |
 Larger image Burner flame is yellow |
 |
Back
to 10 things for troubleshooting water heater 10) power vent water heaters Power vent water heater can vent combustion gas through a sidewall vent. How it works: "When the thermostat senses a need for hot water, a valve is opened which allows gas to flow to the closed solenoid valve. As gas pressure builds up within the solenoid, the gas pressure switch closes and 24 VAC flows to the blower relay. The blower relay contacts close and send 115 VAC to the vent blower which turns it on. Air flow from the vent blower closes the air pressure switch sending 24 VAC to the solenoid valve. The solenoid valve opens and allows gas to flow to the burner which is lit by the pilot or igniter" Blower: less than 5 amps consumption @ 120 volt. 120 volt x 5 amp = 600 watts running with 1200 watts start-up. Resources: Power vents: Power vent water heater issues Anode covered by power vent |
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Blower Power vent water heaters use a blower to vent gas by-product from water heater. Blower requires 120 volt grounded outlet. Electric outlet for power vent and flue damper water heaters should be dedicated, and surge protected. Do not use extension cord for power vent and flue-dampered water heaters. Blower is connected to gas control valve with a wire, called the control cable. The gas control uses a firing sequence to activate the blower and start moving air upwards just before the burner fires up. Blower, control cable, gas control valve, and pressure switch are part of troubleshooting. Eliminate the obvious: Check the blower first, and gas control valve last. Buy blower: Water heater blowers at Amazon Blower troubleshoot Test pressure switch Power vent troubleshoot Troubleshoot hot surface ignition How to check blower motor Check blower motor |
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Pressure
switch or vacuum switch Generally, to check if blower is good and pressure switch is bad, you bypass the pressure switch and connect blower directly to 120 volt outlet, running a pigtail to the blower or plugging blower directly into outlet. Pressure switch troubleshoot Test pressure switch Air pressure switch testing Intellivent wiring Pressure switch replacement Bradford White pressure switch replacement Check pressure switch |
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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 |
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 Venting power vent models Read product manual for venting specifications Example power vent manual p17 Minimum vent distance from window Power vent tables Power vent troubleshoot Typical power vent manual Typical power vent manual2 Typical service manual Gas venting specs Conditions where outdoor air supply is needed |
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 |
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 Typical manuals Typical power vent manual Sample Rheem Gas water heater manual AO smith Service manuals |
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Back
to 10 things for troubleshooting water heater 11) Venting combustion byproduct Do not use aluminum vent pipe. Use 3"-4" steel galvanized, stainless or PVC pipe. During water heater combustion, hydrogen content of fuel is burned, resulting in hot gases that travel upward and out the vent pipe. Obstructed vent will slow or halt combustion, resulting in tripped ECO, yellow flame instead of blue. Adequate venting or air draw up vent is required so gases vent outside. Atmospheric vent has no blower or mechanism to assist upward flow of vent gasses. The venting action is a natural upward flow of hot air, plus the natural upward convection of air. Power vent and flue-damper water heaters push vent by-product up the vent pipe. If blower or pressure switch or firing sequence is not functioning, the vent gasses do not travel up vent pipe. Negative air pressure Wind Rusted flue pipe -or water dripping down 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 Buy: Carbon monoxide detector Vent tape Water heater vent hood Simple test for proper venting: Check that pipes are not rusted or covered with white condensate. There is no water on top of tank. Burner inspection does not show excessive rusting. Steps: Turn off water heater and wait 1-2 hours for heat to stop rising from tank. Hold lit match within 1" of vent hood and see if smoke is drawn into vent. If smoke does not draw, then check for vent obstruction on roof, or call plumber. Resources: See image of test Vent draft test Gas venting specs Square footage per BTU Ventilating tight-house/ pdf Pilot outage and negative pressure |
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Soot
on top of heater also implies danger of improper vent and
backdraft. Improper location of vent on roof, and incorrect clearances, or windy location can stop vent gas from leaving vent pipe. If vent gas cannot escape at top of pipe, it can be entering house at the vent hood. Soot on top of heater is evidence. If pilot goes out, the improper draft can be blowing out pilot light. Soot on top of heater can be caused by backdraft where vent gasses are being blown back onto water heater because of shared vent pipe with furnace or other gas appliance. Read next section. |
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| Backdraft
Is your furnace causing water heater
to malfunction? Furnace, kitchen-bath bent fans etc can affect vent
draft on water heater. Called negative pressure. Is there evidence of rusting etc on top of heater, next to the draft hood? Is the furnace room particularly cold or wet? This is evidence of backdraft. Here is a simple, but telling test. When the water heater first fires up, a little heat will spill from the draft hood. It should only spill for a second or two under normal circumstances. So, with the furnace off, turn the temperature on your heater up to cause it to fire up (you might make a mark on the thermostat dial so it can be put back to the same place). Quickly, put the back of your hand to the draft hood to feel any heat spilling out. Count the seconds. Return the heater to normal. Now wait a bit and fire up the furnace. Feel for any spillage at the water heater draft hood with the water heater off. Count seconds. Now fire up the water heater (furnace running) and check for spillage again. If furnace and water heater both vent into same chimney, the draft might not work properly. Water heater should have dedicated vent. For example the chimney vent pipe is is eight inch, but the two vents (from furnace and water heater) going to it are both four inch. That bigger vent might be oversized and hard to warm properly for good drafting. If the furnace is power vent, and fan or vent will overpower natural draft. Having the furnace and water heater vents combined will cause problems. Likely the right fix is to run two, separate three inch vents. |
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| Water
on top of
heater. Rusted vent pipe. White condensate on pipes. Inadequate draft, or improperly installed vent pipe can cause condensation inside pipe that will rust and cause white condensate. Missing roof cap will cause water on top of heater that will rust out the water heater. |
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 Never install more than 1 elbow on sidewall vents Straight shot is always best shot. Elbows slow venting and cause backdraft. Resources: Gas venting specs Direct vent clearances Conditions where outdoor vent is required |
  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 |
CO poisoning If joints fall apart, or vent is improperly installed, hot gases enter home posing risk of odorless CO poisoning. Symptoms: headache that goes away when outside in fresh air. Unconsciousness. Remove affected people from home and lay on sides, not on back. Call emergency help. call plumber. Attach vent pipe sections with 3 screws and then cover joints with aluminum tape. Buy: Vent tape Carbon monoxide detector |
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 How
to test water heater draftLet main burner operate for 5 minutes. Then put match near vent hood. Smoke from match should get sucked into vent Resources Water heater vent test/ pdf Checking the draft Read more at Tank |
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