We have a Heat and Glow vented gas log fireplace that is about 7 years old. It is used very seldom and may go an entire winter season and only be used once or twice.
About 3 months ago we noticed an odor even though the unit was not being used. The odor is not constant or at the same level of severity. We seem to notice it more on an overcast day.
We called the installer and had the gas company check it, but they did not find any problems. At the installers request, we ran the unit for about 6 hours to "Burn off" anything that may have accumulated on the firebox. We also cleaned the firebox as best we could, but there is no way to get to the back of the unit.
This has been very perplexing !!! Can anyone help ?
Some fireplaces take longer than 6 hrs to burn off. Hearthman should be able to give you a more accurate time frame for that unit. I would figure the smell is a intermittent down draft situation (negative air pressure) caused by dryer, bathroom fan, or other exhaust type units. It doesn't take much to fight a pilot flame and it does give off a slight odour if it spills into the room. Consider installing a fresh air make-up kit (hole in the wall) in the furnace room to neutralize pressures.
I was thinking the same things as NG Tech as I read along. What has changed in the house over the yrs? New windows? Exhaust fans? Added forced hot air/ AC unit?
Dust will settle on a fireplace and the burn off is referred to as "fried dust syndrome". You can smell this at your furnace or water heater, too. If it is a chemical smell, it could be aldehydes from leaking combustion chamber or acrylic adhesives such as on foil tape or a new glass. If the glass is old, it might be losing its seal.
The bottom line is, someone needs to test for CO first. Then Dx the odor. Try wiping the heat exchanger area and anywhere accessible in and around the unit other than inside the combustion chamber. Use a citrus based solvent cleaner (orange stuff). Follow with Febreeze.
If the odor is due to a foreign material in contact with the Fp, it usually takes at least 8-12 hrs Straight to cook it off. That's a minimum time--could need more. However, if there is something inside the chase such as wet insulation, dead animals, etc. the odor will not go away.
Also, airborne molecules hitting a hot surface can form stinky compounds. Houses are full of aromatic things. I can smell kids toys, candles, Bounce dryer sheets, etc. when I walk into a home. I zero my gas sniffer outside and it always rises as I enter a home--always. There are tons of hydrocarbons floating around that we breathe in.
You need to rule out other causes and sources. What's down in the basement? Outdoors? Does it go away if you open a basement window on the upwind side? How long does it take to manifest? Does anything make it go away? What about correlating wind & weather? Exhaust fans in the home?
Contact HG Customer Service and Support with the model and serial # and they'll be glad to help as much as they can.
The fact that is did not stink before usually indicates a change around the Fp and not intrinsic to the unit itself.
Keep the fire inside the fireplace.
“We seem to notice it more on an overcast day”. The reason is the column of air in the chimney on cool overcast days is heavier then the air inside your home allowing it to DROP. Also a pressure difference (Delta P) will allow the air in the chimney and fireplace to enter the home!
Gas tech "Consider installing a fresh air make-up kit ('HOLE IN THE WALL') in the furnace room to neutralize pressures."
The correct term is "EQUALIZ-(air)" Pressure
The quality of my performance, sometimes depends on the quality of my audience.
Imitation (Plagiarism) is the best compliment one can get -- "Open A Window"
To improve Indoor Air Quality: Control Indoor Air QUANTITY = "I.A.Q.Q."
X, nice "shameless plug".
Thanks to each of you for the quick response. I will develop a methodical approch after studyng your suggestions and do my best to only change one thing at a time so I will better understand the root cause of the problem.
One complication :
The fireplace is on an inside wall of a large den area with a 20+ foot ceiling that opens into the upper floor of the house. To accomodate the chimney or flue pipe, there is a large "Box" that contians the fireplace and mantle. This creates a large sealed unvented area inside the house. It seems to me that that smells could accumulate inside this space and escape wherever they can. This space could easily be vented into the attic or I could also vent it into the chimney that continues past the roof line.
Is the vent fan you mention a commercial unit that I can purchase locally ?
wfr, Don't vent that cathedral ceiling into the attic! You will be creating another greater "chimney" effect in that room, increasing problems.