Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

10 seconds of oil smell when oil furnace starts up

Ricky248 Member Posts: 3
When my oil furnace (forced air, no boiler)  is starting up, and I'm sitting or lying on my bed,  I smell oil.  The smell lasts only 5 or 10 seconds and stops either when or before (not sure) the blower starts circulating air through the house.     Now that my computer is in the basement, I spend hours only 25 feet (and around the corner through an open door) from the furnace and I never smell oil.   Though once i noticed the smell when I was on the landing from the first floor to the basement.  My nose is about 5 feet  off the floor!   I haven't noticed any smell  in the kitchen, or on the rare occasions when I'm standing right next to the furnace and it starts up, but I have smelled it in another bedroom where I used to have the computer.   Both br's are on the second floor.   When I'm lying down in my BR, my nose is only about 2 feet from the duct, and sitting at the desk in the other BR, only about 4 feet .   

I found that the furnace has been using a hollow nozzle, when the name plate on it calls for a hollow nozzle.   Could that be (part of) the problem?

The 2 year old CO detector in my BR reads zero, and the 8 year old CO detector also reads zero.    (Is there any point to keep using an 8-year old detector?)

Thanks a lot.


  • earl burnermann
    earl burnermann Member Posts: 126
    how old is furnace?

    Some furnaces use temperature to start the fan but new ones are on a timer. I'm taking a wild guess that you have a oil spill, maybe in the blower cabinet that needs to be cleaned up. Could just be a small amount in the blower cabinet.

    There was an error rendering this rich post.

  • billtwocase
    billtwocase Member Posts: 2,385

    crack in the heat exchanger? I would have it checked. Could be an inspection door, or clean-out access port, delayed ignition, rotted or disconnected smoke pipe, partially or plugged chimney, down draft, and countless other causes. Have it checked by a pro.
  • add
    add Member Posts: 94
    cold chimney

    My question is ,does this happen only on a cold start or every time the burner fires up,some pics of the smoke pipes would be helpful,i don't think you have an oil leak otherwise you would smell the oil constantly,maybe a slight delayed ignition so i suggest to check for carbon around the nozzle and retention head.
  • Ricky248
    Ricky248 Member Posts: 3
    Sorry for late reply

    Sorry for late reply**    Thanks Earl, Billtwocase, and Add for your replies.

    The furnace is 34 years old.  Out of work,  I can't afford a new one now, and I'm not the only one in the n'hood who is still using the original furnace.    If there is a spill in the blower cabinet, would that be more easily smellable upstairs when the fire starts, but before the blower starts?  It seems like the blower would increase the smell, but by the time it turns on, the smell has gone away.  

    Delayed ignition sounds likely.   What is the cure for that?  I checked the electrode gap, and I changed the ignition transformer (to one just as old.  With the old one it was stopping for no apparent reason.)     What else should I do to fix delayed ignition?

    It used to happen every time the furnace started, since the new nozzle I'm not sure.  I don't notice it as often.  There was definitely oil and lumps of oil residue on the nozzle and the electrodes when I took them out to change the nozzle and adjust the electrodes (which didn't need adjusting) . How do I stop delayed ignition?   :-)

    There might be a crack in the firewall.  I have some 4 minute smoke

    pills.  IIUC, I can light one, put it on a shelf in (or just throw it

    in????)  the firebox, and if there's a leak, smoke will come out of the

    grills at the ends of the ducts.  Is that right?    Any details on how I

    should do this?

    **I waited until I replaced the nozzle to see if that changed anything, but the previous nozzle was also Solid, as is supposed to be used.    And I had to replace the ignition transformer, from my spare burner.   And then I want ed to re-evaluate the symptoms.  It's heating well and for a while I thought the smell was gone.  It's surely not as often as it used to be, and I continue to only smell it in the bedroom, not the kitchen where I can feel the heat when it goes on.

    Thanks again.
  • oldtech
    oldtech Member Posts: 1
    odor diagnostics

    I realize this post has likely been taken care of but for someone looking through the posts for a similar problem, this is for you. This is a classic case of a cracked oil furnace heat exchanger. As the heat exchanger heats up with the blower idle the fumes seep out of the opening and exit in the room closest to the furnace until the blower starts and then the compartment is pressurized and the odor is dissipated. Many times the odor will be smelled in the bathroom or a bedroom depending on the layout of the house and the location of the furnace. In another post someone mentioned using a smoke candle. Unless you know how to properly use one don't waste your time. Diagnosing this type of problem is not really for the do-it-yourselfer, this one you have to bite the bullet and call in the pros with the tools and the experience to do the job right.
  • Kakashi
    Kakashi Member Posts: 88
    Tight house

    Do you have a whole house fan?
  • Coany
    Coany Member Posts: 91
    good thorough annual service been done?

    make sure that chimney base is clean. and the fire is adjusted properly,

    There was an error rendering this rich post.