Yellow Flame even after Furnace Service

[Baharra]

I'm in an on-going fight with my gas company. All my appliances are gas (water heater, range, furnace). My gas usage had doubled from the previous year, for no reason, so I asked the gas company to check on it, they changed the meter at my house and sent it out for testing. It wasn't long after that when I noticed that there were yellow flames with little to no blue on all my appliances. This is especially noticable when the furnace is running. I have had the appliances serviced, the gas company told me to call 911 to have the fire department check for CO in the house, there was none, the gas man finally came out to the house and told me he had never seen anything like this before. He changed the meter again and checked the pressure at the furnace, everything checks out. He told us we just needed to adjust the air mix in the furnace, we called the heater service man back out, he checked everything again and said the furnace was fine, there was nothing to adjust. I am at my wits end. Everything I read online says not to use gas appliances when they have a yellow flame, but then I won't be able to cook, shower or heat my home and it's 20 degrees outside already. Both the fire department and the appliance service people say it's the gas or something in the gas lines (i.e. rust got knocked around when the gas company changed the meter, etc.), but the gas company keeps trying to blame my appliances. I'm to the point where I'm considering purchasing a new gas range, because that's the least expensive and the easiest to change out just to prove someone wrong. Please help.

[ecman51`]

I've never heard of anything like this before either. All 3 appliances suddenly became affected?

Is it to hard for you to disonnect your side of the meter, after shutting it off, and disconnect at one of the appliances and air compressor blow through the line? Possibly back-blowing it toward the meter direction?

Trouble is, if there was that problem of say rust scale or some film, perhaps every appliance now has clogged orifices, where just cleaning the main line will not help resolve that. You may be in for cleaning every appliance. Hopefully the valves are not affected. That would not be good if they were.

Go out by your gas meter and see if you have a 1/4 or 1/2 foot dial and run the furnace and time that fast turning dial. Tell us what your furnace's input btu rating is on the name plate in your furnace. And tell us which fractional dial you have, and how many seconds it takes to make one revolution. As an example my 80,000 btu input furnace takes about 12 seconds on my new 1/4 cu. ft. dial (it used to be 1/2 foot but they upgraded meters).

[mbk3]

At first glance I would probablybe looking at the pressure from the meter set. Low supply pressure will produce yellow flames if the supply pressure is below the appliance regulator pressure. Or a restriction in your line, such as a partially closed valve or a physical blockage somewhere. Even a leak in the house piping could reduce the pressure, though you would most likely smell it, unless it were underground.

[Grady]

It's possible when the meter was changed, they broke some crap in the lines loose which now have plugged the intake screens on the gas valves causing low pressure on the outlet side of the valve while the inlet side is fine.

[Baharra]

So, this morning, I was going to check the dial and everything like you asked me to, but first checked the stove, just on a whim and the flame was ALL blue. I don't think I've EVER seen a flame looking that nice on my stove. I'm so thrilled that it's fixed. I didn't do anything it's all yellow for 2-3 weeks and then everything is serviced, two days go by with a completely yellow flame and then this morning, POOF, it's better than it's ever been. Thanks so much for all the help. Of course I'm still curious as to what changed. Is it possible that the gas from the gas company was just of too poor a quality? Either way all better, but have to go out and buy new pots and pans since all of mine are now a lovely sooty black. ;o)

Thanks again.

[Grady]

That is indeed strange. I've seen it go the other way but never yellow to blue.

[Baharra]

I had also recently purcahsed an UltraSonic humidifier and in the past couple evenings have noticed a very fine foggy smoke throughout the house. Thought this was something that happened after the furnace was cleaned or something, but turns out, it was my humidifier. If I leave the humidifier off at night, the flame on the range is a nice blue the next morning, after running the humidifier during the day, the range flame is all yellow when I'm making dinner. I've done this two days in a row now. Today I'm going to leave the humidifier off all day and see if the flame is still blue this evening.

I guess I must have a defective unit. It's brand new, not dirty and not getting the house "too humid" - I've checked with a seperate Humidistat. Without it running the house is far too dry, but I can't have it making my flames yellow and who knows what crap it's putting into my air to make those flames yellow.

Thanks again for everyone's help.

[Gunguy45]

Baharra
Have you also noticed a fine white dust on the horizontal surfaces? I had that issue way back when I had an ultrasonic room humidifier. It was explained to me that it was the minerals in the water.

[Baharra]

I've read about these issues as well and there is no white dust. I even looked specifically for this issue after I realized the humidifier was the likely culprit all along.

[Grady]

I suggest documenting your findings with a video then contacting the local health department. Something is really wrong if the humidifier is causing the stove to burn yellow.

Please keep us up to date on your findings.

[ecman51`]

Sounds like the humidifier is over humidifying.

When I was little kid, my mom put a humidifier in my bedroom when I was sick, and I remember that fine fog. Those things really pumped out the steam.

I could see how something that extreme may affect a flame.

[wisefolly]

Originally Posted by ecman51`

Sounds like the humidifier is over humidifying.

When I was little kid, my mom put a humidifier in my bedroom when I was sick, and I remember that fine fog. Those things really pumped out the steam.

I could see how something that extreme may affect a flame.

I doubt that it is the high humidity along that is causing it. My range keeps a blue flame even in the crazy Philadelphia summers with 80 or 90 percent humidity.

I wonder if Baharra's humidifier comes with the silver ionizer (if I'm getting this right) that mine does and if that would affect the flame. (I'm not a scientist, mind you, so I could be completely off.)

I've been boiling water on the stove off and on today to increase the humidity in my apartment (bad, I know, but I kept a close eye on it). The flame was blue, and there was no problem. After setting up my humidifier tonight, even below 40% rh my range is giving me a yellow flame since running it. I'm going to keep the humidifier in my room tonight instead of in the kitchen and see if it improves tomorrow.

I did some research online, and it did say not to use the humidifier near gas appliances (mine is not near the range). However, I thought that was only because of the risk of a spark. Interesting. Let me know if you find out more!

[SeattlePioneer]

I think a humidifier could cause such a problem. Most gas burners are bunson burners, which means that a jet of gas is directed past an air shutter that sucks in air to mix with that gas.

This allows an air/fuel mixture to be formed which burns on the top of the burner forming a blue flame. Without that bunson burner mixing in that primary air, you'd get a candle like flame with a blue base and white flames composed of incandescent carbon atons that then can burn completely once they reach an oxygen rich atmosphere at the edge of the flame/air boundary.

That kind of candle like flame is safe, but only if it burns fully in air. Put a pot, pan or other obstruction in the way that intereferes with that delicate combustion process and you get incomplete combustion, forming carbon monoxide, soot, aldehides (an alcohol) and other chemicals produced by that incomplete combustion process.

The blue flame with that injection of primary air prevents that incomplete combustion phenomena from occurring.

With too much in the way of water droplets entrained in that primary air stream, you can probably cool off the flame too much, again producing incomplete combustion, white flames and possible carbon monoxide hazards.

The same thing can come from having the primary air shutter open too much --- the excessive primary air cools down the flame too much and can cause carbon monoxide and other problems of incomplete combustion.

[wisefolly]

Perhaps you are right. You seem to have much more scientific knowledge than I do.

However, if it is the level of the humidity, why would my range still work in 80% humidity in the summer? Also, Baharra did say she checked the humidity with a separate humidistat, though maybe it was inaccurate if she was seeing fog in the air. (honest question)

I don't know. It just seems odd. I couldn't find anything saying that it could be something other than the humidity though, so I guess you are right.

Ugh! My skin is so dry now though, I would hate to think that I can't use the humidifier because of this.

[SeattlePioneer]

I don't know that I'm right.

However, droplets of water entrained in combustion air would have to be vaporized from the heat of the flame, and it takes a good deal of energy to convert water into steam. That might be enough to cool down the flame and prevent complete combustion.

High humidity would already have water in a vapor, not requiring that extra energy for the change of state between liquid and gas. And there might be a lot more water in air processed by a humidifier than simple high humdity.

But I'm really just guessing. I've never heard of the kind of problem described before.

But gas flames are quite sensitive to chemicals contaminating the combustion air. Drying paint and pool chemicals sitting in a pool boiler shed can cause odors and corrosion problems.

It might be interesting sometime to turn on a humidifier in the vicinity of a gas range or other burner and see if it can produce that kind of effect. It might be possible to document an original effect of that kind of contamination of a combustion air supply.

[wisefolly]

An interesting experiment yes, but not one I'd sign up for. (Though I would love to know the answer)

Ozone from the ionizer in the humidifier, plus the risk of static from the electric appliance, plus gas could easily cause (Hehe, I know the icon is meant for anger/flaming, but I couldn't resist using it. I mean, there is fire shooting out of its head.)

Okay yeah, it's time for me to go to bed now. Losing coherence past 2am EST.