Water Heater Burner

How to improve the performance of the water heater burner. Find out about the proper gas combustion and the flame pattern. How to clean and replace a gas burner for the efficient water heating.


Gas water heater burner is probably the most important element in water heating. Based on the fuel source, two types of burners are used: steel when the heater is using natural gas, and cast iron when the heater is using propane (LP) gas.

Gas burner is part of the burner assembly which contains elements such as: thermocouple, main orifice, main gas supply tube, pilot burner, pilot orifice and pilot burner gas supply. All these elements should work properly, be free of the dirt, otherwise the burner won't light or the performance will be reduced.

Correct burner flame pattern

Water heater burner will produce a stable flame only when there is a correct amount of fresh air coming into the combustion chamber. The best way to inspect the flame pattern is through the small viewport located at the bottom of the unit. The correct gas combustion should generate a soft blue flame where some yellow inner cones are allowed, and the flame is drawn into the draft hood. Soon after the start-up, the burner will radiate and glow in the bright orange (it usually takes 30 seconds).

A lack of oxygen will cause the gas burner to produce an unstable flame pattern which changes the color into yellow and flattens out. The lazy, yellow flame is usually the first symptom of the more serious problem, sooting.


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Burner inspection

It is recommended by the experts and manufacturers to inspect the water heater burner assembly at least once a year. It can be done often, which depends on the usage and operating conditions. The water heater burner should be inspected with and without the flame.

The reason for the inspection is to ensure that when the gas is burning, the correct flame shape and color have developed, and there are no obstructions on the burner ports, main line and orifice.

If using the insulation blanket to reduce the stand-by heat loss, make sure that the air openings are free of obstructions also.

Sooting is what you should look for. Sooting is recognized as the smoking and carbon formation. This is a very serious problem related to gas burners, which will affect not only the proper gas combustion but your health or damage the property. If this problem occurs, turn the unit OFF immediately.

How to remove the gas burner

  • Turn the gas supply to the water heater OFF at the manual shut-off valve.
  • Turn the thermostat dial on the gas control valve to OFF.
  • Remove the outer door.
  • Disconnect the elements from the manifold assembly: gas valve, pilot tube, thermopile...
  • Remove the manifold assembly.
  • Remove the burner by unscrewing the bolts.
  • Keep its chamber sealed, and if, for some reason, gaskets are removed, they must be replaced.

Burner cleaning

Water heater burner cleaning should be done from time to time as part of the regular maintenance, to prevent any dirt coming into the gas line, orifice and burner gas ports.

While cleaning the burner and combustion chamber, you might find the black dots on the elements as the result of corrosion when the condensate is dripping on the hot surface. This is what causes the sizzling and popping noise.

Follow these steps for the correct cleaning:

  • Turn the gas control valve to the OFF position (you might have to push the knob in slightly).
  • A ring filter at the bottom, which protects the unit from lint, dust and dirt, should be cleaned by using the vacuum cleaner. This way, the gas burner will be free of debris and will get the sufficient amount of fresh air.
  • Remove the inner door.
  • Remove the main burner for cleaning.
  • Inspect its ports and the orifice for obstructions and clean the scale deposits and debris with a wire brush.
  • Clean the combustion chamber and flame arrestor plate also by using the compressed air.
  • Do not let any large debris stay inside the burner.
  • It is allowed to use vacuum cleaner, hot water and soap for cleaning.

And keep in mind that the water heater burner should generate a smooth and light blue flame with a minimum of yellow tips.

References

rheem.com
bradfordwhite.com
kenmore.com

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