Black Soot from HVAC

[K]

Hello! I recently moved and find that the carpet in my new house, though clean otherwise, has a black sooty stain all around the baseboard. I called some carpet cleaners to come by and take a look and they told me it was from the gas furnace, but couldn't be any more specific. Does anyone know what causes this problem and what I can do to prevent it from getting worse. I probably don't need to point out that I know nothing about these systems (moved to the midwest from CA where we didn't need forced air). Any help would be greatly appreciated. Thanks!

[DIDO]

There is no reason for soot with gas furnace unless you furnace never being clean out since installation which I would not be surprise. You should shut off furnace open bottom and gave it good clean out with vacuum upon completing. re light the furnace and pay attention that there is no blockage where the air mixture takes place your flame should be apx. 80% bluish if flame is white that is part that create the soot Note this cleaning should be done ones a year on furnaces and your hot water heaters. Good luck from Dido

[Zephyr]

You are all correct. But, the soot appearance on the carpet indicates the house envelope has gone positive, meaning there's a return duct leak, [or there is a fresh air intake in the return] so the system is pushing more air in the house than the system is taking back out, the result is the house has gone positive, causing any excess air to leave through the baseboards [especially around the edge of the carpet] and show up as dirt smears or sooting. Usually shows on light color carpets the most. Probably in the living room, dinning room areas the most. [Door traffic brings in dirt to the home and is being pushed down through the carpet [acting like a filter.].

I could be wrong here, but I've seen it before.

[DIDO]

You right Zephyr also I would check for what I posted earlier at wrong place From: "DIDO" Subject: Re: Electric Furnace Wiring Date: Saturday, April 08, 2006 11:05 AM

Check your furnace for internal leakage "carbon monoxide" Dido

[noaddress]

[Oscar_Lives]

Sounds like you have an underpowered analog thermostat on your furnace. The problem is that the analog thermostats do not properly interface with the AS (anti-sooting) circuitry in the furnaces ECC emmision control center.

Replace the old thermostat with a proper digital thermostat (it is easy--you can do it yourself). Make sure the digital thermostat has ASC capability (most all of the higher-end digital thermostats have this built in.)