soot,flame lapping out

My friends gas fired furnace have a lot of soot accumulation in front below the flue box.The vent pipe and chimny is not blocked. I did notice the flames tend to leap out from the burners toward the front,also two of the burners have sort of tall yellowish flames. Any ideas? Thanks. Bela

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Hi:bela

The condition your discribing here is extremely hazardous. It's known as smothering flames in the firebox. This condition needs to be checked by your gas utility service person and a licsensed heating agency, as soon as possible!

Smothering flames are caused by a lack of oxygen. The condition your discribing means there is lots of unburned gas seaking oxygen to burn. Thus the flames are coming out towards the front of the burners.

Yellowed flames are caused by a lack of secondary air to the burners. The yellow flames cause the soot. As the soot builds up, it clogs <restricts> the flues exhaust vents at the top of the firebox, further compounding the lack of air problem.

This condition is producing high amounts of carbon monoxides, which may be entering the house. It's also an extreme fire hazard.

It may already be too late to correct the smothering problem. The firebox may also have a crack in it or be too sooty to clean.

If the furnace is too old, a replacement firebox may not be availible either.

I highly recommend, for your friends personal health and safety, he/she have this checked immediately! I suggest they not use this furnace until it's fixed, corrected or totally replaced.

Since I can't see the furnace first hand, I hope you don't think this is an extortionation discription of the problem.

Have the furnace checked ASAP!

Regards

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Sincerely,
TomBartco
TomBartco Enterprises.
Trade:Natural Gas Energy Consultant & Technician.
Appliance Service & Repairs Rep.
Vocations:Saw & Tool Sharpening. Small Engine Repairs.
Accurate Power Equipment Company.

Personal Quote:
"Drive Safely. The Life You Save, May Be Your Own."

 

turn that furnace off and get it checked!
as tom said this is a very unsafe condition, and needs to be addressed ASAP

 

Tom, Thank you for your prompt reply.Rest assured that i very much trust and velue your opinion Bela

 

Am new to this site so didn't know if to post my question here or where. Was wondering if the diagnosis for a central heating unit, that has tall yellow flames from burners and also flames leaping towards front of unit, is same as the bela's problem?

 

Yes..... Anytime flame floats out of heat exchanger it is producing c/o. Not venting properly.. Restricted heat exchanger.. DO NOT use until repairs have been made!!! Extremely dangerous

 

I'd like to add a known phenomenon that people over look: Downdrafting of chimney(s). Yes..plural. I worked as maintenance man on a commercial building with 5 roof exits for air, counting chimneys and kitchen ventilation and general ventilation, and even venting of the elevator shaft at the roof .

What I discovered, when oil burner smoke was being drawn out of the oil-fired boiler (one of those prehistoric jobbies), was that the basement had a drafting problem. Up drafting was greater at the other chimneys and actually pulling air *down* the oil-burner chimney (a big chimney, free and clear of any creosote/soot, I might add!. You could feel almost hurricane force winds (I'm exaggerating just a tad) coming down the chimney before the oil-burner fired up. And when it did fire up, after it had cooled down betwen cycles...that is when the hot air no longer rose up *this* chimney, but rather the basements warm air (the basemetn was heated) chose to go up the other vent routes, like when the kitchen fan (huge unit) was on. Even with the furnace room door closed, it still wanted to do this, and I scratched my head, and then went about plugging holes in the furnace room that was allowing air from the basement/kitchen area to get into the furnace room. I ended up curing the problem, pretty good.

But now..no worry. New owner, new heating system.

But with a house, the same scenario can happen. It can be windy out. If your house leaks, the wind blowing past your house can create a vacuum in the house, and you can get a down draft from a lone chimney. Or, if windows are open and you don't know it. Or, if bath fans or range fans or dryers are pulling air out of the house. Then when you fire up the fireplace, the smoke can try to come out the front of the fireplace until the firepkace or stove warms the chimney enough to ovrcome the downdraft. Air pressure/temperature inversions can cause this also.

I recommend that the person having flames or smoke that heads back into a room rather than up a chimney, to check the drafting of the chimney, like with toilet tissue held inside, or held right in front of the burner access or inspection door, to see what is going on.

 

A PG&E inspector wrote in his notes that my furnace has a recirculating flame and soot in the chamber. Is this the same condition?

 

It could be. You need to have it checked out by a professional.

 

I hope he capped your furnace and issued you a hazard notice...Sounds like same condition as original post