Yikes .... Oven Flames

[rvexodus]

Let me start by saying we are at 9000ft elevation. I used the oven a couple times and didn't notice any issues. I have to kneel down to see that the pilot light lites (electric ignitor). The couple of times I used the over when we got to our campsite all was good. Flame was about 1/2-3/4" from the oven burner. Just recently I lit it up and the flames are easily hitting the sheetmetal above the burner. If the sheet metal wasn't there I would estimate the flames at 4-5". Really.

Everything else seems to be ok. The stove burners appear normal ... maybe slightly higher. But one wouldn't notice. Furnace exhaust did seem hotter but it was 34 degrees outside so a napkin would feel hot 🙂

So here is what changed. We refilled our tanks at 5000ft elevation. Anyone experience this? Could this be a tank pressure issue? I tried it again after running the furnace a bit and we still had the massive flames in the oven. Regulator issue?

Thanks, Kirk

[rvexodus]

And I just called suburban as the manual doesn't indicate any adjustments. Suburban / Airxcel simply said that because I'm over 4500ft they can't help me ... well thats nice. Do they not realize a significant number of RVers travel over 4500ft.

[rvexodus]

Matt_Colie wrote:

Kirk,

#1 It should be safe, but the flame may deposit soot on the bottom of the oven bottom plate and the bottoms of pots used.

#2 The problem is the lack of oxygen. There is probably (I don't know your specific hardware) an air adjusting collar near the jet of each burner assembly. You could slide it (there is usually a screw that holds it) more open and the yellow flame tips should be reduced. The flame size will still be larger than expected, but that should not matter.
If you plan to get back below about 5KMSL, and that air sleeve is still set for 9+KMSL, the burners may go lean. They can go too lean to stay burning. This is not a good thing.

Matt

Matt, thanks for the follow up. I'll pull the manual and see if I can find and adjustment on the oven. The stove burners seem normal to the most part. I've attached a photo of the over burner for reference.

[Matt_Colie]

rvexodus wrote:
Thanks folks and Matt for you explanation. All makes sense.

I did relight a couple more times and did notice there were a few flames that had orange tips .... not all across the long over burner but in some places there were orange / yellow flames. This I know to be an oxygen issue. I do have a suburban stove SRNA3. I believe there are a few variants of this model. Mine has the stainless front as well as elec ignitor. I know this stove has a couple of different manufacturers of the manifold as well.

I'm guessing this may be more of an LP (everything on the floor) butane propane mixture issue as I'm 84.3% certain this issue occurred after we refilled our tanks.

#1 question. Is this safe and what should I do about it if anything? #2 Is the problem oxygen or fuel or a combo of the two?

Thanks again ... interesting topic ....

Kirk,

#1 It should be safe, but the flame may deposit soot on the bottom of the oven bottom plate and the bottoms of pots used.

#2 The problem is the lack of oxygen. There is probably (I don't know your specific hardware) an air adjusting collar near the jet of each burner assembly. You could slide it (there is usually a screw that holds it) more open and the yellow flame tips should be reduced. The flame size will still be larger than expected, but that should not matter.
If you plan to get back below about 5KMSL, and that air sleeve is still set for 9+KMSL, the burners may go lean. They can go too lean to stay burning. This is not a good thing.

Matt

[rvexodus]

Thanks folks and Matt for you explanation. All makes sense.

I did relight a couple more times and did notice there were a few flames that had orange tips .... not all across the long over burner but in some places there were orange / yellow flames. This I know to be an oxygen issue. I do have a suburban stove SRNA3. I believe there are a few variants of this model. Mine has the stainless front as well as elec ignitor. I know this stove has a couple of different manufacturers of the manifold as well.

I'm guessing this may be more of an LP (everything on the floor) butane propane mixture issue as I'm 84.3% certain this issue occurred after we refilled our tanks.

#1 question. Is this safe and what should I do about it if anything? #2 Is the problem oxygen or fuel or a combo of the two?

Thanks again ... interesting topic ....

[Retired_JSO]

If the flame has turned to yellow tips, a small critter/insect may be reducing the air to the burner resulting in a higher but yellower flame.

[ReneeG]

Great information Matt_Collie - my question here would also be, to add to the conversation, what brand of oven/range does the OP have? Perhaps different brands have different adjustments or issues?

[BB_TX]

In other words, if it has an adjustable opening on the burner for air then open it up a little to let more air in so the flame will burn quicker and shorter and bluer.

[Matt_Colie]

Ready Kirk??

Hang on because here we go....

The absolute pressure in the tank is related to temperature and fuel mix exclusively. You may think it is propane, but notice the sign says "LP Gas". it is usually a mix of largely propane and with some butane and what ever else they swept of the floor. So, that is not an issue.

The regulator (whether single or two stage) should (Note: Should) deliver fuel to the appliance at a constant pressure of 11 inches of water column (W.C.) and this is referenced to local air pressure. So the absolute pressure can vary with altitude, but it will only be lower with increasing altitude. So, that is not your issue.

The burners used in gas appliances are pretty much all the same. They use the velocity of the incoming fuel to drag along the atmospheric air to make the desired fire. This is where your problem shows up. Because there are fewer pounds of air (by mass) per cubic foot at 9KMSL, the fuel needs to drag in more air to burn. It can't do that very well, so the flame front has to get farther from the burner to get to the more air that it needs to have to burn.

If some of that slipped by you, and or my explanation seems incomplete (this is very likely also), please try again and I will try to fill in what ever is missing.

Matt

[ReneeG]

Hmmm, we've camped many times at 9k elevation and have never had flames like that.

[Horsedoc]

Higher the altitude you are at, the lower the pressure. Pressure from the tank/regulator remains the same and makes the flames higher. Old engines w/o turbos were affected the same way