As part of maintenance to the gas furnace, you need to adjust the gas burner. For the furnace to work efficiently, flames on the burner should not only be full but steady, and there should be no sputtering or trace of yellow. Adjusting the height of flames on the main burners should be done with great caution. If you do not know the proper way to do it, make sure that you seek professional help.
Adjusting the pilot flame height should not be too hard. All you will need to do is to twist the adjustment screw of the flame till the flame goes from one and half inches to two inches, which is about 4 to 5 centimeters high. Look for the adjustment screw on the pilot assembly close to the gas valve if the control valve has this adjustment feature.
If you notice any on the surrounds of the furnace unit, you will need to create a mixture of detergent and water and then paint it on the connections and valves of supply line of the gas. This mixture will produce bubbles at any point where there is a leak. You need to locate the point of leak and then try tightening it using a pipe wrench. You should however do it with extreme care not to over-tighten the connection. If after doing that you still notice pipe connections or valves still leaking, you will need to seek professional help.
Before you start doing the adjustment of the gas burner on the furnace, make sure that the electric power to your furnace is disconnected and its front panel has been removed. By doing that, you will still be able to see the gas flames inside or under the burner and it will make sure that you are not at risk for an electric shock.
You also need to inspect the quality of the flame before going on with the adjustment. If the gas burner is producing straight, pure blue flames, it means that the furnace is functioning properly. But if it is producing yellow or blending flames, you will need to start with cleaning the furnace before you proceed to adjusting the gas burner. The furnace will also be in a good working condition if it is producing blue flames with greener edges or blue flames with small yellow tips.
When cleaning the furnace, you will need to turn the gas off at the valve and then clean the pilot nozzle, or the place where the flame shows up, using a wire brush. Use a flashlight to make sure that all debris is removed from the area around the burner nozzle and the pilot light. After that, you can put the furnace back on full power and check the color as well as quality of the flame. If you cleaned it properly, the flame will be blue and straight or it might still have a little yellow in it.
It is important to check burner flames and pilot lights at least once every month as part of regular maintenance of the furnace. And also ensure that the furnace is inspected after at least every three years with a professional.