Ask Me Help Desk

Ask Me Help Desk (https://www.askmehelpdesk.com/forum.php)
-   Heating & Air Conditioning (https://www.askmehelpdesk.com/forumdisplay.php?f=150)
-   -   Wood stove (https://www.askmehelpdesk.com/showthread.php?t=296786)

  • Dec 29, 2008, 02:40 PM
    stickfort
    wood stove
    I built a 36in. Dia X 40 in.wood stove from 1/4 in. thick gas line pipe. The chimney is fabricated from 6 in. stove pipe which  passes through a window opening and run up the side of the building.  The overall length of the stove pipe is 15 ft. The top of the pipe is 3 ft. above the peak line. My isuue is (1)it take a long time to heat the area. (2) Smoke pours into the room every time I open the access door to load wood. Any suggestions.
  • Dec 29, 2008, 03:27 PM
    hvac1000
    First I hope you are not paying for any homeowners insurance since they will not pay off on any fire if they find that stove in your home or believe there was one there that was not listed. All stoves have to be UL or CSA listed or labeled and installed according to code. I have nothing against home made stuff but I always give this warning since most people do not know the rules.

    A back draft is what you are having a problem with. Many times this is caused by the chimney being to short or the chimney cap is of improper design. It can also be caused by negative pressure in the home. Clothes dryers vent fans, and other items can cause a negative pressure situation which is allowing the smoke to be pulled back into the room. If the chimney has a better draw it will usually overcome this problem. Now some wood burners have what is called a smoke shelf built into them that also helps eliminate this problem. Good luck.
  • Dec 29, 2008, 03:44 PM
    21boat
    15' of chimney is a tad short. To check your chimney natural draft take a section of stove pipe out. Light a match and see if it can suck it out backwards or a real good flicker, if not chimney pulls is to weak need more height on chimney. Is this stove ans air tight set up and or are there any adjustments to allow added air in stove while burning? When you burn a stove that is very tight very air tight or closed down in its air intake adjustments this only allows so much air up the chimney. When you open the door and pull air back towards you that effects the chimney slow air current and for a second or two the chimney air flow is all but stopped for moment. IE smoke into room when door is open. Assuming the stove is good and chambered or not inside, If you have air inlet adjustments on stove front open them up first to get the chimney drawing faster wait a bit open door. Now open See how that does. The other thing we've done on jobs is setup another air intake for chimney usually from outside so the air in the chimney is always faster and less creosote build in chimney, gasses gets out of the chimney quicker. Do you have a baffle in stove pipe before chimney? If not one would be good. When you burn the stove you can adjust that for the airflow to slow down the wasted hot gases leaving the stove and the stove heats better. This baffle is simply a flat piece of metal with a rod through it to flip the metal and if you do have on Open that first then the stove air inlet adjustments fully opened. Now open door slowly. The reason I mention a baffle in the wood stove this is metal shelf that the smoke in the stove goes around to help eliminate your problem and also keeps the stove gasses traveling in the stove longer and makes the stove heat hotter and its more efficient.

    Signed 21 boat

    If I helped answer your question please rate this answer
  • Dec 29, 2008, 04:12 PM
    hvac1000
    http://www.woodheat.org/technology/noncatalytic.gif

    The ten perfect rules of install for wood burners. Now lets face it not all installs are perfect but these will give you some ideas.

    ONE The chimney runs inside the building envelope (inside the heated space) so air and flue gases stay at least as warm as the air in the house until they are expelled outside.
    TWO The chimney penetrates the highest part of the building envelope so the chimney always functions better as a chimney than the house does, even when there is no fire burning.
    THREE The chimney is tall enough and its top is clear of obstacles to wind flow so it can produce stable draft and it has a chimney (rain) cap because without one any chimney is vulnerable to adverse wind pressures.
    FOUR The chimney flue is insulated and is the correct size for the appliance so flue gases are kept warm and flow quickly through the system.
    FIVE The flue pipe (if there is one) runs straight up from the appliance to the chimney and the chimney has no offsets because each change in direction presents resistance to flow.
    SIX The appliance and venting system are reasonably well-sealed because leaks introduce cool air and big leaks make the system more vulnerable to adverse pressures.
    SEVEN The stove or fireplace is EPA/CSA certified for low smoke emissions or has equivalent characteristics (like masonry heaters do) so it is unlikely to smolder because smoldering appliances are much more likely to spill smoke.
    EIGHT The system is installed in a house that may be tightly sealed but has a balanced ventilation system. The alternative, exhaust-only ventilation, cause houses to be constantly depressurized and is disastrous for chimney vented systems.
    NINE There is no large exhaust fan (like a downdraft kitchen range exhaust), or if one is present, it is electrically interlocked to a fan-forced make-up air system to prevent the house from becoming excessively depressurized when it operates.
    TEN The appliance is operated by an informed user because the best of designs can be disabled by improper operation and a lack of maintenance.
  • Dec 29, 2008, 05:48 PM
    stickfort
    Quote:

    Originally Posted by hvac1000 View Post
    First I hope you are not paying for any homeowners insurance since they will not pay off on any fire if they find that stove in your home or believe there was one there that was not listed. All stoves have to be UL or CSA listed or labeled and installed according to code. I have nothing against home made stuff but I always give this warning since most people do not know the rules.

    A back draft is what you are having a problem with. Many times this is caused by the chimney being to short or the chimney cap is of improper design. It can also be caused by negative pressure in the home. Clothes dryers vent fans, and other items can cause a negative pressure situation which is allowing the smoke to be pulled back into the room. If the chimney has a better draw it will usually overcome this problem. Now some wood burners have what is called a smoke shelf built into them that also helps eliminate this problem. Good luck.

    Thanks for the input would an insulated stove pipe on the outside of the building help my issue, also the sove air inake is the wood loading door.
  • Dec 29, 2008, 05:52 PM
    stickfort
    Quote:

    Originally Posted by 21boat View Post
    15' of chimney is a tad short. To check your chimney natural draft take a section of stove pipe out. Light a match and see if it can suck it out backwards or a real good flicker, if not chimney pulls is to weak need more height on chimney. Is this stove ans air tight set up and or are there any adjustments to allow added air in stove while burning? When you burn a stove that is very tight very air tight or closed down in its air intake adjustments this only allows so much air up the chimney. When you open the door and pull air back towards you that effects the chimney slow air current and for a second or two the chimney air flow is all but stopped for moment. IE smoke into room when door is open. Assuming the stove is good and chambered or not inside, If you have air inlet adjustments on stove front open them up first to get the chimney drawing faster wait a bit open door. Now open See how that does. The other thing we've done on jobs is setup another air intake for chimney usually from outside so the air in the chimney is always faster and less creosote build in chimney, gasses gets out of the chimney quicker. Do you have a baffle in stove pipe before chimney? If not one would be good. When you burn the stove you can adjust that for the airflow to slow down the wasted hot gases leaving the stove and the stove heats better. This baffle is simply a flat piece of metal with a rod through it to flip the metal and if you do have on Open that first then the stove air inlet adjustments fully opened. Now open door slowly. The reason I mention a baffle in the wood stove this is metal shelf that the smoke in the stove goes around to help eliminate your problem and also keeps the stove gasses traveling in the stove longer and makes the stove heat hotter and its more efficient.

    Signed 21 boat

    If I helped answer your question please rate this answer

    Thanks very much for your input, the sove is located in a garage and the fresh air intake is controlled by the wood feed door. Also would there be a great improvent if I used a double walled stove pipe on the outside of the building?
  • Dec 29, 2008, 05:56 PM
    stickfort
    Quote:

    Originally Posted by hvac1000 View Post
    http://www.woodheat.org/technology/noncatalytic.gif

    The ten perfect rules of install for wood burners. Now lets face it not all installs are perfect but these will give you some ideas.

    ONE The chimney runs inside the building envelope (inside the heated space) so air and flue gases stay at least as warm as the air in the house until they are expelled outside.
    TWO The chimney penetrates the highest part of the building envelope so the chimney always functions better as a chimney than the house does, even when there is no fire burning.
    THREE The chimney is tall enough and its top is clear of obstacles to wind flow so it can produce stable draft and it has a chimney (rain) cap because without one any chimney is vulnerable to adverse wind pressures.
    FOUR The chimney flue is insulated and is the correct size for the appliance so flue gases are kept warm and flow quickly through the system.
    FIVE The flue pipe (if there is one) runs straight up from the appliance to the chimney and the chimney has no offsets because each change in direction presents resistance to flow.
    SIX The appliance and venting system are reasonably well-sealed because leaks introduce cool air and big leaks make the system more vulnerable to adverse pressures.
    SEVEN The stove or fireplace is EPA/CSA certified for low smoke emissions or has equivalent characteristics (like masonry heaters do) so it is unlikely to smolder because smoldering appliances are much more likely to spill smoke.
    EIGHT The system is installed in a house that may be tightly sealed but has a balanced ventilation system. The alternative, exhaust-only ventilation, cause houses to be constantly depressurized and is disastrous for chimney vented systems.
    NINE There is no large exhaust fan (like a downdraft kitchen range exhaust), or if one is present, it is electrically interlocked to a fan-forced make-up air system to prevent the house from becoming excessively depressurized when it operates.
    TEN The appliance is operated by an informed user because the best of designs can be disabled by improper operation and a lack of maintenance.

    Thank very much for your answers! This stove is located in my garage/workshop. The air intake is the main wood insert door. Would insulated stove pipe outside the building greatly improve the chimney draft?
  • Dec 29, 2008, 06:08 PM
    mygirlsdad77

    Are you saying you are using single wall stove pipe. As hvac said, you will be in quite a mess if there is ever a fire. No insurance company will cover this install. I also like to see homemade things, but you best be careful. I actually don't care what the insurance companys say, but I would worry about the hazard to you and your loved ones lives.

    On another note, you should use triple wall insulated pipe.

    I have a friend that had a homade stove in his detached double garage. The stove was actually there when he bought the place. It was about as safe as you could get, but the insurance company came out to check the place, and made him buy a manufactured stove, or they wouldn't cover the house, garage, or land. If you can get this thing to vent properly, good on you. Just know the possible consequences. I truly hope this thing works out for you and there are never any problems(insurance or otherwise). Good luck and take care.

    Just my thoughts,

    Lee
  • Dec 29, 2008, 06:30 PM
    hvac1000
    There is a special pipe called Metalbestos that works very well for a wood stove.

    Selkirk: Ultra-Temp Series 5'' - 14''

    There are also other brands but the solid packed pipe is the best. Tripple wall pipe depends upon air to keep the sections cool and are great for metal fireplaces but not for wood stoves.
  • Dec 29, 2008, 06:47 PM
    21boat

    Yes it would improve it a bit. Another 2 or 3 of chimney would do more. I assumed it was an insulated chimney. Now here the other catalyst. Its very important to keep the chimney gas's hot to the top. It stops creosote build up and fires. It sounds like you set up what we call here a farmers furnace. First see how hot the top of the chimney is at the top metal sides. If its to cool then yes an insulated is better. BUT 26 gage 6" smoke pipe is cheaper to experiment put another 2 feet on and see how if any changes your draw and hotter top. Is the Chimney 2 ft above any object in radius the first rule of thumb. If the chimney is still cool the insulated chimney would be on the list. (I will get busted here for saying this) I would try a T fitting outside where the elbow is and remove elbow use T. for the bottom you can get a metal cap. Now you have a ash drop not to clog chimney at elbow. On that bottom of T I would take some tin foil and experiment and pop some holes in it to get a little more air up the chimney. Now the foil is just for testing. If it helps the cap ash pit can have some small vent holes in it for faster chimneys draw strength and push the hot gases up quicker to heat the top of the chimney. I have been building masonry chimneys since 79 and sweeping them out You get to see a lot of situations and how stoves and chimneys react and learn some good tricks. Don't foreget the foil was temp replace with smoke pipe metal cap.

  • All times are GMT -7. The time now is 10:29 PM.