Brand:Frigidaire Model Number:FGF355AUD Main Symptom:Not Burning Properly What happens & when:My Frigidaire oven does not burn properly at startup. The heater/ignitor runs, valve opens, and flame occurs near the air metering inlet, prior to the actual burner. Everything is very, very clean. This is an LP stove. The problem only occurs with the bottom, oven burner, not the broiler or top burners. Jet is an M46-56. Also very clean. This situation occurs probably 80% of the time. Sometimes it will clear itself, others I shut it off. I call it burning back. It makes a whistling, waffling sound.
Thanks!
Error Code (if any):None
Parts or tests already tried:Cleaned & visually checked
Photos / video link:
What you’re describing sounds like burner flashback, where the flame travels backward through the burner and burns near the air shutter or venturi instead of staying at the burner ports. The whistling or fluttering noise is another indication of this condition.
Since this is an LP gas range and the problem only affects the lower bake burner, I’d concentrate on the bake burner’s air/fuel mixture, burner positioning, and gas pressure rather than the igniter or electronic control.
I would avoid using the oven until this is corrected. Flashback can overheat the burner inlet, gas valve connections, and surrounding components. If you smell gas, shut off the gas supply, leave the area, and contact your gas supplier.
Here is what I’d recommend checking.
1. Inspect the bake burner positioning. With the gas and power off and the oven cool, check that the burner tube is properly seated and aligned with the gas valve orifice. Make sure it hasn’t shifted, warped, cracked, or developed enlarged burner ports. Even a clean burner can cause flashback if it is damaged or improperly positioned.
2. Check the air shutter setting. LP gas requires a different air/fuel mixture than natural gas. Excessive primary air can contribute to flashback. Check whether the bake burner has an adjustable air shutter and whether it is loose or excessively open. Don’t make an arbitrary adjustment; it should be set according to the manufacturer’s LP specifications.
3. Verify the LP orifice. You mentioned an M46-56 jet. I’d want to confirm that this is the correct LP orifice for the bake burner on model FGF355AUD. A clean orifice can still cause problems if it is the wrong size. Also, don’t drill or enlarge the opening.
4. Check the LP gas pressure. Incorrect or fluctuating gas pressure can cause unstable combustion. A qualified gas technician should measure the manifold pressure with a manometer while the bake burner is operating. Many LP ranges are designed for approximately 10 inches of water column at the manifold, but the exact specification needs to be verified for your model.
5. Inspect the burner ports. Even though everything is clean, look closely for corrosion, enlarged openings, or damage around the burner ports. A deteriorated burner can allow the flame to travel backward toward the inlet.
My main suspicion is an issue with the bake burner’s air mixture or burner tube, especially since the broiler and surface burners operate normally. However, proper gas pressure still needs to be verified before ruling out the supply or regulator.
I have two questions that will help narrow this down:
Has this range always been set up for LP gas, or was it converted from natural gas?
When the flame burns back toward the air inlet, does it happen immediately when the burner ignites, or does the burner light normally and then the flame travel backward after a few seconds?
That second detail is particularly important. It can help distinguish an ignition or flame-carryover problem from a combustion-mixture issue.
Thank you very much for replying. This Frigidaire range was converted from natural gas to LP. There is a sticker affixed stating same. I did not buy the stove or install it. It came with the place. I’ll try to answer some other helpful suggestions. The manifold assembly is all one piece, is very clean, and is non-adjustable with the exception of the air intake. There is no adjustment in the relationship of the manifold to the jet. All components have predetermined and pre-drilled locations in the appliance. I’m assuming they are correct. I wouldn’t change them anyway. While I’m replying I can’t see your helpful reply, going by memory. The flame burn back happens as soon as the valve opens for the oven to burn. Occasionally it happens shortly after startup, but either immediate or pretty soon thereafter, seconds not minutes. I have not tried to adjust the air mixture yet. Someone else has, because I can see the screw impression in a different location than its present position. The jet is a M46-56 which according to an Internet search appears to be a correct LP part. I do not have means to check the gas pressure. In the oven, the burner has a diffuser or spreader above, and then the oven pan, both that require removal to view the flame. Necessary to perform adjustments. I think your suggestions are correct, I just preferred your advice with this appliance.
I think my only option is to adjust the air to the flame in the hopes that I can get both a proper burn, and to eliminate this persistent burn back.
In continuation, I embarked on adjusting the air mixture sleeve, noting it was probably open too much. I adjusted it once by reducing the opening and tried it again, better, but still not right. Got the bright idea to measure the opening width on the broiler manifold because it works fine, and uses the same jet as the oven. That measures almost exactly 1/2’’ wide. When I say more, possibly 1/32” more. I retrieved a piece of finely machined tooling from the garage. Shaft exactly 1/2”. Use that as a gauge tool. Adjusted the opening, tightened things up. Fired it up and it works properly through many start-stop cycles.