White powdery substance

Can anyone tell me what a white powdery substance could be in a burner chamber of a gas heater? There is a small half inch pile at the end of the heat chamber. I know, I should have taken pictures :roll:. The white powder looks like baking soda.


I can tell you but Im not sure you will believe me. I had a hard time believing it at first but became convinced. My brother in law worked in the gas service industry for about 40 years. He and I were discussing things one day and I asked about that.

He told me that very often the air is laden with chemicals in the form of vapor. He used perfume as only one such example but he said it could be anything from cleaning fluids, deodorants, mens cologne, etc., etc… He went on to tell me that when those fumes or vapors come into contact with a standing pilot light or any open flame it will develop a very fine ash that falls to the surface below it. If you think about it that makes sense as the ash is alwasy right below the pilot and there is usually only a small amount.
He found out what it was when he would go huge plants, mills and factories that were using a lot of chemicals and the air would be very heavy with the fumes or vapors. He did some research, asked some very smart people and they all told him the same thing. Incidently, in those plants and factories, gas heat exchangers in those big overhead gas blower furnaces would burn out in half the time as normal. He would end up on numerous call backs and would always find the white powdery ash deposits. I have noticed since then that on gas ranges you will sometimes find the same ash around the wires for a Piezo electric igniter on the burners.

That would be very correct Doug common house hold chemical pine-sol any ammonia based chemical cleaning products can cause this I have seen the powder all up in the heat exchanger

Can it also be caused by incomplete combustion of the gas, for whatever reason?

Yes it can

I asked that and he said no. Fumes and vapors from airborne chemicals. Whenever we say chemicals everyone, including myself, always think of industrial stuff but he said and Charley confirms it. Anything that outgasses with fumes and vapors can cause it.
In the words of Inspector Cluoseau. “We have essolved de case”

OH good! you say it can. I am going to snap his garter next time I see him.

Larry incomplete combustion is probably not a real good choice of words as most people think of incomplete combustion as low combustion air which creates black soot. In Actuality incomplete combustion can also be on the opposite side where you are over firing the burner to much oxygen and burning hot which can cause a mixture of white to red tinted substance to form as a result of the metal overheating.

Well he did have air fragrance plug-ins in almost every outlet in the home:mrgreen::mrgreen:.
Thanks guys for the info


Lemme guess, the furnace was in the laundry room, or by the washer…

Want to see some white powder this is the inlet to the draft divirter on a 1977 carrier still in use installed in the hall closet with two local returns floor level.

I was once told it is from too high of a humidity level.
Found it in a B vent

One can be told anything its whether you believe it. Gotta watch those two horse cities :wink:

I once found a bag of cocaine on the smoke shelf of a fireplace. Coincidence…I think not.

This is not exactly under the burners, but near them. Might airborne chemicals be the source of this powder rather than condensation?
You can see from the second photo that there was a problem with condensation.