Chimney & Fireplaces/fireplace wont draft

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Question
our fireplace place is a freestanding Malm all glass fireplace... it was working great... NOW it will not draft and fills the house with smoke.. we do not have a manual damper so we can not control that... we have tried everything... any ideas?

Answer
Hello Wendy,  Fireplaces smoke and or odors are the #1 problem we are asked about and it can happen for a number of reasons, dirty chimneys, nests, blockages, improper construction of a chimney, improper use and Negative Pressure.  Let’s start with mechanical Negative Pressure, this includes kitchen/bathroom exhaust fans, attic fans, radon systems, clothes dryers, another fireplace, even the boiler/furnace.  They all vent house air to the outside. A furnace return also pulls air out of the house and recirculates it in the home. Now, on to the hardest problem to figure out.  “House stack effect” of Negative Pressure, this is hot air rising in the home, creating positive pressure on the upper floors and negative pressure on the lower floors and in most cases the hot air that is rising in the home is getting out though attic doors, ceiling lights, vents and windows and cold air and odors can be pulled down a fireplace chimney to feed the home. Chimneys work on a simple principle of hot air rising and pulling more air in behind it. Now let’s look at the whole house as a chimney, that’s right, I said the house. If the house is air tight, then the hot air will only rise so far and stop.  If you have a pull down attic door, attic fans with louvers, or any other opening that will vent air out of the house, then your house is acting like a chimney, the air is going out through those gaps and spaces and when the air leaks out, the house needs make up air and it will come from the path of least resistance- the fireplace (one fireplace can also feed another). Other things that can cause this are lights in the ceilings.  The bulbs are hot and the top of the “can” they sit in is not sealed so the hot air goes up. Air rises up a staircase, toward the exhaust fans that are drawing air even when they’re off. Now you know why you are getting the air/smoke down the fireplace chimney when you are not using it and when you try to start a fire. Sometimes by just opening a door or window a few inches will relive the pressure of the house (breaking the pressure) and allow the chimney to draft and the house to breath.  Now, when you light a fire, the air is hot from the fire (hotter than the air in the house)  and it will reverse the down draft and allow the fireplace to work properly. When the fire is going then you can shut the window or door and burn your fire (usually 2-3 minutes). The only draw back to using a fireplace this way is that as the air in the fireplace dies down and cools, then the “House Stack Effect” will take over and may draw air, smoke and odor down the chimney again. If air is going up the chimney it needs to come from somewhere. The house needs make up air or find the outlet that is venting your hot air out of the house.here is a YouTube video on it (Google it too) https://www.youtube.com/watch?v=AN4X9jPJdqI
I would have a local Certified Chimney Sweep www.csia.org, (there you can look up by zip code to find one near you) take a first hand look at what you have, they should be able to help.
Hope this helps
James  

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James Ball

Expertise

I am a chimney sweep with over 22 years of experience, CSIA certified and member of the NCSG, I can answer questions about smoky fire places, wood stoves, and heating units (boiler and furnace chimneys) do you need a relining? A cap? And much more

Experience

over 22 years

Organizations
Chimney Safety Institute of America, National Chimney Sweep Guild

Education/Credentials
CSIA (Chimney Safety Institute of America) certified

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