Outdoor Wood Furnace Info

All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: unaslob on January 05, 2010, 09:21:23 PM

Title: too much draft?? or not enough??? that is the question.
Post by: unaslob on January 05, 2010, 09:21:23 PM

For awhile now I have thought that i have too much draft...why.. i dunno.  but tonight as the snow falls with my boiler temp... i asked myself do i have enough draft????   How does one know???  I have a natures comfort owb (ncb250) buring coal with a coulple logs mixed in. for the past couple of weeks i thought i was getting too much draft as others with the same setup limit their draft by lowering the opening on the draft fan.   i have been restricting my draft by placing something over about 1/3 to 1/2 of the fan opening as i cannot lower the door easily.  when I have a good fire going... I open the door to check it out and see hot coals hot wood..very small flames then there is a big flame up of very large blue flames that remain as long as I leave the door open.   If I close it for about 2-3 min and reopen it, same thing, small couple of flames..then the eruption.  this is not after adding coal recently so i dont think it is the early volatiles burning off...i seems like the extra surge of oxygen allows more of the volatiles to burn off and thus create heat!  So i removed my restrictor from the draft looked at the fire about 5 min later and pretty much the same thing..the only way I can keep it roaring is to crack the door open about 1/4 inch... not a good long term plan... How do I solve this age old dilemma, too much draft, or not enough??? more importantly how do i fix it?

Title: Re: too much draft?? or not enough??? that is the question.
Post by: mikenc on January 07, 2010, 07:13:39 AM

I have seen same problem with mine. It may not be same with yours but mine was stopped up flue. If flue is stopped particially you will still get some combustion but not enough. Opening door gives combustion air making it burn. Check inside fire box and make sure flue is not blocked with ashes as well as inside pipe.

Title: Re: too much draft?? or not enough??? that is the question.
Post by: boyland on January 15, 2010, 11:57:26 AM

When I burn coal I increase the air flow a lot almost wide open to hit my heat numbers.  JMO but burning coal takes a lot more air.

Title: Re: too much draft?? or not enough??? that is the question.
Post by: unaslob on January 23, 2010, 09:39:07 AM

what kind of coal are you burning?  what stove do you have?  I have been "natural drafting"  meaning that  I do not use the fan.. I just vary the opening of the ash pan.     It is working for me for now.

Title: Re: too much draft?? or not enough??? that is the question.
Post by: Smokey on February 16, 2010, 06:18:46 PM

I get the same problem, it seems it comes and goes.  I have found the flue partially plugged before, But a good clue comes from the smoke. When this is happening, is there alot of white smoke, or is it burning clean?