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oil furnace smell...YUK!!

Hello, I am new to this so forgive me if I'm not doing something right. I asked this question on the ask TOH section already but it may not get addressed there so I am asking through this section. I was wondering if anyone has any idea why my house reeks of kerosene from my oil furnace. I hate it!!! I notice it mostly when the wind is blowing. My husband called the furnace guy at my request and he came over yesterday and cleaned this and that on the furnace, and today, the furnace is blowing stinking kerosene odor still. My husband thinks I'm a bit crazy, but I am serious when I say that this smell occurs when the wind is blowing. I can be in the house and smell the smell and say...gee the wind is blowing....and I am right. So let me know what you think.
Thanks so much

Re: oil furnace smell...YUK!!


First and foremost.....do you have a quality digital read-out carbon monoxide detector in the house? If not......get one immediately...is my advice. (Plug-in Nighthawk model (or better) and not a cheapie model that only tells you when CO concentrations in the air have reached a critical state as regards your health.) The reason for this advice will beome clear as we delve into the various reason(s) that can cause what you describe.

You don't state that there are any "booms" when the furnace/boiler starts or not. Frequently there are when oil-fired furnaces or boilers are malfunctioning, but not always.

You also haven't said whether or not you see evidence of soot near the heat registers or similar. This can be very helpful in diagnosing a problem and/or alerting a homeowner that something is amiss.

The smells you describe can be caused a worn-out or partially clogged nozzle which no longer throws the nice pattern it is supposed to. When this ideal pattern is lost, the oil may not combust completely as it should. What is supposed to be a nice pattern of finely atomized particles will be something less than that and can degrade to the point of being mostly a squirting stream of fuel. Any degradation of the pattern frequently/usually results in incomplete fuel combustion which means more carbon particles/soot, which can begin clinging to the fire-pot, the heat exchanger, the flue and the chimney walls. When enough of this soot collects inside, it restricts/blocks off some of the chimney draft necessary to carry the exhaust out of the device and out of the chimney. When this happens and the furnace keeps firing to satisfy the thermostat's call for heat....there is a high likelihood that some of these exhaust gases will escape into the house. Along with the gases will be a strong odor of the oil as well as deadly carbon monoxide. http://www.carbonmonoxidekills.com/

In a worse case scenario, the nozzle is so worn out or clogged that it shoots a solid stream which cannot be properly combusted and the excess/unspent fuel simply saturates/soaks the walls of the fire-pot, etc.

To recap - Might be a bad nozzle and/or a bad nozzle combined with a partially clogged heat exchanger, flue or chimney.

Another possibility is that the nozzle is okay, but the fuel-air mix is out of whack. In order to burn the fuel efficiently, combustion air is required........at the proper proportion to the injected fuel. Too much air is not good (too hot of a fire) and too little air is not good (incomplete combustion). On numerous occasions over the years I have discovered the air-ports down by the fuel-gun assembly clogged with dust-bunnies. This can happen pretty easily depending upon just where the furnace is located. This might be the/a cause or contributor to your problem or maybe not. Dust bunnies are easy to remove.

Another possibility related to the above is the source of the necessary combustion air supply. Where is your furnace located? Is it in the open area of a basement, in an enclosed utility room or...???? If out in the open of a basement......is it a leaky old stone-walled basement or a nice new tight one? Without a sufficient supply of combustion air from outside the house.... it is easy to deprive the combustion process of all the air it needs which would lead to an imbalanced air-fuel mix. Lack of sufficient air will always to a "rich" mixture which in turn leads to soot/carbon-particle production. This can readily lead to the paritially, or even totally blocked off, draft flow. It can also create negative pressure inside the house which means that the likelihood of exhaust gases entering the home thru some small open seam or crack in the flue pipe increases.

Another possibility is that your heat exchanger has a hole or crack in it. How old is the furnace/boiler? This would be another very serious situation and it can be nearly impossible to see without some disassembly of the furnace/boiler....but would be evidenced by the prescence of CO in the air.....particularly so if it has already been ascertained that there is proper drafting of the flue pipe as well as up the chimney. Therefore, proper exhaust drafting should really be the very thing to check. If you don't have it, then the reasons why must be discovered and remedied. (Clogged heat exchanger, clogged flue pipe and/or obstructed chimney.)

Also.....the barometric flue damper must be properly adjusted to assure proper drafting under various outdoor wind conditions. Without proper adjustment of this device, you would be sending valuable and expensive heat unneccessarily out of the chimney on windy days.

The same holds true for the flue pipe leading from the furnace/boiler to the chimney; if it has a hole or crack in it.......odor and CO will enter the house........sometimes without any accompanying soot to give away the crack. It depends.

And here is another possibility base upon your description of this occurring mostly on windy days - Your chimney is either too short for where it is located or it has some cracks/holes in it which allow for the making of a down-draft inside the chimney. This could/would push some of the exhaust gases out of the barometric draft control unit.

Or another wild guess/hypothetical - Your house is "older" and drafty to some degree. When the wind blows outside it creates negative pressure inside the home which then sucks exhaust gases backwards out of the furnace or flue pipe. This would more likely if the furnace is getting its combustion air from inside the home and/or the heat exchanger, flue or chimney are already partially obstructed.

There are other similar possibilities/scenarios, but I think you get the basic notions concerning potential problems. And again, my advice is to get a CO detector immediately if you don't already have one.

And maybe/ probably ??? a different furnace guy to look things over.......if a little spilled fuel isn't the cause of this odor. Spilled fuel could be the only cause as the odor can/will linger for a quite while after a spill if it isn't cleaned up thoroughly and quickly. If the cause of the odor is from spilled fuel on the floor or similar, try dumping a little ground coffee on it and leaving it there for a couple weeks.

PS- Do you have a fireplace ? If so, windy days could cause drafts up this fireplace chimney....causing spilled fuel odors to be drawn up thru the house.....or even cause exhaust gases from the running furnace to be sucked back into the house.

Re: oil furnace smell...YUK!!

Another problem that Goldie didn't mention. If this is an old house that was built for wood or coal heat, when new heating system were introduced they were often vented into very large chimneys with no consideration to being able to supply enough flue temperature to get proper draft. As newer more efficient units are installed the problem gets worse and on windy days the flue is often back drafting. A complete inspection may be called for by a qualified heating contractor not a tech whose just cleans a few things. An yes you should have a CO monitor.

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