Thread: Gas fireplace makes soot streak on siding.

What are the possible causes and what is involved in repair? I will always call for service by a qualified gas tech, but would like to elaborate, likely cause, expected costs, etc.
I have talked to clients about gas log placement and they seem sceptical.
I have mentioned that some gas logs produce more yellow flame and therefore more soot, and they just looked at me like I was making this s... up.

When the fireplace glass becomes cloudy, does this indicate a leaky gasket? Easy fix?

Pic 1 and 2 are at a townhouse, the neighbour's unit is leaving soot on the soffit cover. 3 and 4 are a 3 yr old home with hardiplank siding.

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Gas logs are probably the cause

Blue flame denotes a proper air/fuel mixture and hence a correct temperature flame.

Hence any thing but a blue flame in a gas fueled appliance probably means not correct blue temperature and the possibility of soot forming.

How to fix?

Read this thread: http://www.inspectionnews.net/home_i...fireplace.html

John, you need a hearth pro in there for several reasons. The first pic shows a direct vent termination too close to a sidewall/inside corner. The second, I cannot see for sure. The third shows some exterior soot staining on the siding. The forth shows the white film that all gas fireplaces create.

In each case, you need a qualified technician to inspect and test the fireplaces. You will need the listed instructions on hand to verifiy the visible clearances, log position, orifice size, gas pressures, etc.

If all hearth appliances ran with a blue flame, we'd be out of business as no one would buy them. See the link JP posted.

As usual, without the make, model and mfr. date code or serial #, you cannot make any specific statements about fireplaces other than refer to a qualified technician.
Bob

Originally Posted by Bob Harper

John, you need a hearth pro in there for several reasons. The first pic shows a direct vent termination too close to a sidewall/inside corner. The second, I cannot see for sure. The third shows some exterior soot staining on the siding. The forth shows the white film that all gas fireplaces create.

In each case, you need a qualified technician to inspect and test the fireplaces. You will need the listed instructions on hand to verifiy the visible clearances, log position, orifice size, gas pressures, etc.

If all hearth appliances ran with a blue flame, we'd be out of business as no one would buy them. See the link JP posted.

As usual, without the make, model and mfr. date code or serial #, you cannot make any specific statements about fireplaces other than refer to a qualified technician.
Bob

Thanks Bob, I saw that thread. No answers there.

Originally Posted by erodriguez1
Is it possible to have soot build-up in a gas fireplace with ceramic logs? Thanks.
"Esteban,
You should always expect ceramic logs to soot up somewhat. Some log sets must have a very specific placement while other manufacturers leave the placement totally up to the homeowner. Vent free logs MUST be in their exact position. With most ceramic logs, you should try to minimize direct flame impingement, which leads to a soot formation.

Proper combustion involves the old fire triangle of heat, fuel, and oxygen and combustion efficiency is time, temperature and turbulence. With gas logs, the soot build-up is usually caused by cooling the flame (such as by impinging on logs or embers or by too much secondary air) along with some inadequate mixing with oxygen. David P. Valley "

Copied from elsewhere.

It is ok for Vented logs logs to touch the flame and cause soot as this allows the closest look to a natural wood fire. ventless on the other hand the flame must not touch the logs and exact placement of the logs is imperitive. In the case of the pictures the vents in the location they are will blacken the areas where the exhaust fumes exit the stack, that is why most of the time the exhaust is vented above the roof line. The logs in the picture are I hope vented because of the glass doors, ventless logs can not have glass doors in front of them. Cobra