Cooktop Flame Too High? Test The Gas Pressure

Home » Cooktop Flame Too High? Test The Gas Pressure

You’re getting ready to fry some eggs and bacon for a weekend breakfast or, maybe, start boiling a pot full of water for tonight’s pasta dinner, but when you turn the knob to ignite the appropriate gas cooktop burner, the flame jumps up way too high. What’s going on here? There may be a faulty component involved and, in this article, Repair Clinic will help you troubleshoot the situation to help determine the exact cause.

How a gas cooktop works

The first step in troubleshooting a cooktop burner flame that is too high is an understanding of how a gas cooktop works, so let’s review what happens when you rotate that knob to light the burner.

Each cooktop burner knob controls a burner valve

Each cooktop burner knob controls a burner valve. When the knob is turned to the “LITE” position, the valve opens, allowing gas to flow from the manifold. As the gas travels through the burner tube, it is directed into a fitting called the venturi where it combines with air to create the proper mixture necessary for combustion.

120 volts of alternating current travels to a spark module

At the same time, a spark switch closes, allowing 120 volts of alternating current to travel to a spark module, producing high-voltage pulses to each electrode protruding through a hole in its respective burner base. The high-voltage pulses cause a spark to occur between the electrode and the grounded burner cap. The gas and air mixture at the burner head is ignited by the spark, producing a flame that can be controlled by the burner knob. By rotating the burner knob clockwise, the flame can grow higher which will cause it to spread wider over the bottom of the cookware, resulting in greater heat. Rotating the knob counterclockwise will reduce the size of the flame, allowing the sauce, oil, or meat to simmer.

The color of the burner flame should be blue with an occasional yellow tip

If the ratio of gas to air is correct, the color of the burner flame should be blue with an occasional yellow tip. If the flame is primarily yellow or orange then the cooktop burner is not getting enough air for complete combustion of the gas. Your cooktop may give you the option of adjusting an air shutter located on the burner valve to allow more air in to correct this problem, but be aware that some cooktops do not allow the gas and air mixture to be adjusted.

Troubleshooting and testing a cooktop burner’s gas pressure

If a gas cooktop burner flame is too high, there is some simple troubleshooting you can start with: examine the burner cap.

Examining the burner cap

Is the burner cap sitting flat on the burner itself? A burner cap that is tilted, or not sitting flat on the burner base, can cause the flame to be higher on one side of the burner than the other. To avoid burning your fingertips, confirm the burner cap is cool, then try reseating the cap to see if that fixes the problem. If not, examine the burner cap for damage. A corroded burner cap or one that is warped can cause an uneven flame. If the burner cap is visibly damaged, replace it with a new one.

How to test the burner’s gas pressure

If the burner cap is in good condition and seated firmly on the burner base, the next step is to determine if the burner’s gas pressure is accurate. You will need a manometer to test the gas pressure. Here are the seven steps you can follow to test a cooktop burner’s gas pressure using a manometer:

  1. Unplug the cooktop’s power cord or shut off the power supply – As a safety measure, you’ll want to make sure the cooktop is not receiving power before testing, as long as that power shut-off doesn’t interrupt the gas flow to the burner.
  2. Use an appropriate-size manometer adapter – Burner orifices come in different sizes, so confirm you’ve got an appropriate-sized adapter for the manometer’s rubber tube to match the orifice you’re performing the test on.
  3. Access the burner orifice – To access the burner orifice for testing, you will likely need to remove the cooktop grate as well as the burner cap. Their components can simply be lifted off although keep in mind the grate may be heavy.
  4. Prepare the manometer – Turn the manometer on and calibrate it if necessary. Read the manometer’s instruction booklet to determine how, but it often only requires a “zero” button to be pressed to calibrate the meter.
  5. Position the manometer’s tube – Place the end of the manometer’s rubber tube over the burner orifice. Make sure the end of the tube fits snugly around the orifice.
  6. Turn on the gas – Rotate the appropriate burner control knob to “High” to allow the gas to flow through the orifice.
  7. Observe the manometer display – Notate the reading you’re seeing on the manometer display screen, then turn the burner control knob to the “Off” position to shut off the gas supply.

Gas readings are measured in water columns

Now how should you interpret the reading you’re seeing on the manometer’s display? Gas readings are measured in water columns. A proper natural gas reading should be between five and eight inches water column, and a proper propane gas reading should be between eleven and thirteen inches water column.

Incorrect orifice installed in the burner?

If the gas pressure shown on the manometer display falls within the correct parameters for natural or propane gas, the high flame problem is likely caused by an incorrect orifice installed in the burner. This can happen if an orifice intended for a different burner on the cooktop is mistakenly installed in the wrong burner or if an orifice intended only for a propane gas supply is used on a cooktop supplied with natural gas (and vice versa). As mentioned earlier, another cause could be the gas and air mixture not being properly adjusted. While not all cooktops allow for this, you can try adjusting the air shutter on the burner valve to improve the gas and air mixture to see if that resolves the issue.

What if the gas pressure is too high?

If the manometer display indicates that the gas pressure is higher than it should be, the likely cause is a defective pressure regulator. Just like its name suggests, a range, oven, or cooktop pressure regulator is the component that controls the amount of gas to be let through to the burner valves. If the pressure regulator is faulty, it may be allowing too much gas to flow through when the burner is ignited, resulting in the flame being too high. A defective pressure regulator will need to be replaced with a new one to fix the problem.

Frigidaire Gas Range Pressure Regulator Replacement (5304498819)

Repair Clinic is your source for DIY assistance

If you need to replace a gas pressure regulator or install a new burner orifice kit, Repair Clinic is your source for DIY assistance. Visit the Repair Clinic website’s “Videos & Articles” section to find the help you need to take on all of your gas range/oven/cooktop repairs. You’ll find relevant step-by-step guides, schematics, diagrams, and procedural videos showing how to install propane gas orifices on a Whirlpool model WFG505M0BS0 gas range, or how to replace a gas regulator valve on a KitchenAid convection gas range (model KSGB900ESS1).

Repair Clinic recommends using only genuine OEM gas cooktop parts

Regardless of the component you need to fix your gas range/oven/cooktop, the success of your repair is dependent on using the genuine OEM part that matches your model. Repair Clinic makes this part of the repair process easy. Enter the full model number of your gas range, cooktop, or oven into the website’s search bar to find a complete list of parts compatible with your model, genuine OEM replacement parts specifically designed to work with appliances from such top industry names as GE, Bosch, KitchenAid, Electrolux, LG, Kenmore, Samsung, Magic Chef, and Hotpoint. With Repair Clinic as your repair partner, you can be confident you’re using the best part to fix the problem.

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