down drafts

[buffermop]

What can be done to control down drafts? I usually get them first lighting the wood stove on a cold day. Got a chimeny cap in place already and flue had been recently cleaned. Once the stove is at operating temp, everything is  ok.

[scootrd]

Alot of times Downdrafts occur because of short chimney stacks. You could add 3 - 4 foot of stack and see if that helps.
They also make special downdraft-deflector caps (They have baffles built in). If you want to experiment and have about $200.00 to drop Try one of these

http://www.northlineexpress.com/item/5TJ-AD-1/Tjernlund-Automatic-Draft-Inducer


One quick and easy fix that costs zero bucks is open a window across the room from the stove before lighting to relieve the negative air pressure or vacuum pressure occurring in your home. Make sure your damper is open full and prime stack before lighting.

Here is a good article for you http://www.chimneysweeponline.com/hodraft.htm

[Pat/Rick]

Too add a bit to scootrd's great advice the top height of a chimney should be two feet above a level line ten feet from the roof surface or two feet above the roofs peak, depending on location.  As well as opening a window or door, you may also try lighting a sheet of newspaper on fire to establish a draft. Many experiments to choose from. Good luck.

                                                 

[charles p]

The solution is HEAT.  Get your heat up as quickly as possible with dry tender or whatever you have.

That's my opinion - not scientific fact - but it could be.

[buffermop]

No automatic dampers being used on the stove pipeing. wife loaded the fire box to the max with wood and paper. I think it was too much exhaust to handle at once. I tried in a smaller proportion to start it up and it seemed to work ok. I have to feed the fire slowly until the pipe and chimeny are brought up to temp.Cellar door is kept open until my pipe thermometer registered in the normal range.

[blind ear]

short chimney:

 If the chimney is on the downwind side of the roof ridge the wind will roll over the ridge and put a downdraft on the chimney. If the chimney is on the windward side of the roof ridge the pressure cell formed by the wind pushing on the roof will cause a down pressure on the chimney.

start a good smokey fire on the windward side of the house and watch the air flow across the roof. Different wind speeds, different foor pitches, different placement of the chimney in locations through the roof coupled with different roof areas or a combination of all these factors can make a chimney smoke.

Getting the top of the chimney into the undesturbed wind flow or having a backflow damper will most likely fix the problem.

ear

[buffermop]

In answer to your questions TM7. I have a 6" stove opening going to a 7" chimeny pipe into a block chimeny of 8x12. Part of the stove pipe goes through an enclosed cellar window into the cement block chimeny.I have a walk in basement with an under basement garage included.

Merry Christmas to all!!!

[Glanceblamm]

No automatic dampers being used on the stove pipeing. wife loaded the fire box to the max with wood and paper. I think it was too much exhaust to handle at once. I tried in a smaller proportion to start it up and it seemed to work ok. I have to feed the fire slowly until the pipe and chimeny are brought up to temp.Cellar door is kept open until my pipe thermometer registered in the normal range.

Those women (to include my wife) can build a very nice little fire but will then quickly smother it out with large pieces of wood and can get those downdraft issues.

I have to feed the fire slowly until the pipe and chimeny are brought up to temp.Cellar door is kept open until my pipe thermometer registered in the normal range

This is the correct way, by then you will have established a nice bed of coals to get the larger stuff started.

[Cornbelt]

We used to have those same issues. So I started opening a window with a fan blowing in.
  Once the pipe heats up and the fire is going good, I turn it off and just leave the window cracked a bit.
 With the fan, the stove has to draft whether it wants to or not. Doesn't take too long.

[blind ear]

buffermop, if you find a solution please let us know what it is and why you think it works. ear

[buffermop]

I noticed the colder the outside air, the more down draft problems we have. The key I found is to start the fire slowly until the stove is heated up and it reverses the draft upwards. Slow and small are the key without adding induced blowers and expensive equipment that is not needed. My stack clearance over the peak of the house is 3 feet, enough to assure draft clearance for the smoke. Thank you everyone for your input.  Merry Christmas

Yes. this means keeping the wife out of my man's cave where the stove  is located!!

[scootrd]

I once owned a rambling old lodge kind of a house years ago. It had a large new addition with a flatter section of roof. There was a large impressive field stone fireplace which separated two rooms and which was a thru design and open to view the fire from both rooms. The entrance door to the house was about 35 feet away and was a large 42" heavy door. I had draft problems with that durn fireplace . Whenever the front door was opened it puffed back..yet more heat went up that chimney than the fireplace ever produced! I finally added an accessory fan to the flu which helped, but was getting ready to add onto the chimney and enclose the thing prperly. I didn't really care for that money pit and sold the house and I believe the new owner converted it to gas and put on some nice doors (which had to be custom made). That chimney was too large in diameter and too short and ran cold...the whole arrangement looked kinda nice and lodgey, but was poorly designed and was a big PIA.

..TM7

Buddy of mine had same setup  -  solved the problem by pouring a new chimney liner to proper diameter then Pipped up the stone chimney, put in place a zero insert Buckstove, and added blowers. ....after completion nice toasty and efficient.

[Rex in OTZ]

There is a formula, seen it once but disremember where, I do know that a wood stove with 6" pipe for proper draft should be 13feet above the fire box, for every 90Degree elbow then subtract 5feet of stack height.
Had a coworker that had back draft problems, especially when the kids ran the bathroom vent fan or especially the dryer, in the end he sold that wood stove and bought another that had a makeup air line with a stack damper and the bi-metallic dampner, allot of how a stove will draw is how the stack sits on the roof (airflow round the home in a wind dynamic area)and how initally the fire is layd.
what works for one stove wont work for every stove each is pacular, like a woman, each requires attention  some more than others.

[SHOOTALL]

If you are using a steel chm. The taller you make it the more trouble you cause. Old wisdom was to make it higher not so now. Codes for these type chm's are changing . The more chm you have the longer distance the flue gas has to heat the inner tube. If to long you create condensation , a bad thing . Look into a H cap or similar . They do not allow a down draft. They have been used for years on both metal and masonary applications. They are easy to install. And wind resistant also.

[buffermop]

Shootall....I have a downdraft cap in place on a pencil flue lined masonary chimeny. I stat fires very slowly after some experimentation, and that slowly reverses the downdraft to an updraft as stack temps rise. thank you for your consideration. I may have found my mistakes.

[montveil]

I have the same problem during cold weather in my small Vermont Castings stove.. Not blaming the stove as it has a 25 foot 6 inch air insulated chimney.
My solution is to use a small heater 5X5 inches 1200 amps with a blower. I place it in the stove opening stuff newspaper around it to "seal it" and run it until the flue pipe or stove is warm to the touch. Maybe 10 min or so.
I light as you normally would using good quantities of newspaper and kindling but I find leaving the door cracked helps the initial draft as I have an outside air supply.
I have been doing this for 4 years and always works.

[thejanitor]

We keep a box fan behind the wood stove to move air around the basement. When I have a rare time the coals are all out and there is cool air coming down the chimney, I build my small tinder pile and some kindling in there and befor I strike the match I take the box fan and put it against the open door of the stove and let it run for a minute or two pushing the warm air up (yes it does blow a little ash but nothing like the stinky smoke smell)  Then I remove the fan and light my fire, it works like a dream because the chimney has been pre-warmed slightly and the motion is already going up the chimney... good luck   thejanitor