Draft issues with stainless chimney

[ErnieG]

I'm having some issues with my chimney in my garage drafting correctly.
I can't seem to get a good draft with it ...I lite it and get it hot and it seems good for a day or so then after that I get a lot of moisture running down the inside of the pipe and it ends up coming out the seems above the stove then I get a terrible smell.
My woods been drying around 2 years now so im confident it's plenty dry .
Its worse on colder and windy days ...I get puffs of smoke back out the draft knobs on the door .
I don't know if the vertical pipe going out the wall is to long at 2' and it's slowing down the draft to much and causing the moisture problem .
Id appreciate any help someone may have .

Thanks
Ernie

 

[Mad Professor]

I think You need to insulate the pipe better on the outside.

 

[ElevatorGuy]

I think You need to insulate the pipe better on the outside.

Looks like a class A pipe outside.

OP, The pipe is clean right?

 

[Marley5]

You must have an air gap between the pipe and the outside temperature...... double walled.
Has nothing to do with quality of wood and everything to do with condensation.
You can buy a rigid liner or pipe insulation.

At our hunting cabin we just put an angle on the exhaust so that everything dripped outside until we could grab double insulated pipe.
Yes it really stinks.

 

[Mad Professor]

Looks like a class A pipe outside.

OP, The pipe is clean right?

It is outside with a long run. If you don't run a hot fire it can be a problem. I've seen that with a brick outside chimney.

You want the inside of flue about stove exhaust gas temp until it goes outside.

 

[ElevatorGuy]

It is outside with a long run. If you don't run a hot fire it can be a problem. I've seen that with a brick outside chimney.

You want the inside of flue about stove exhaust gas temp until it goes outside.

I’ve never seen anyone insulate a class A pipe outside. Mine is about the same length as the op and I’ve never had that issue. My stove is way different though.

 

[Mad Professor]

It is outside with a long run. If you don't run a hot fire it can be a problem. I've seen that with a brick outside chimney.

You want the inside of flue about stove exhaust gas temp until it goes outside.

I’ve never seen anyone insulate a class A pipe outside. Mine is about the same length as the op and I’ve never had that issue. My stove is way different though.

I never tried to run one outside. Regardless you are trying to keep gas ~ 500 oF until it leaves the chimney.

Class A will/might do that until how cold and what heat input?

I’ve never seen anyone insulate a class A pipe outside. Mine is about the same length as the op and I’ve never had that issue. My stove is way different though.

Do you run it hot , or try to do overnights?

My current one is inside a full traditional fireplace, SS insert insulated and capped. Clean it every other year.



College years neighbor ran his woodstove into his outside fireplace chimney. "flue is so big, I never had to clean it..."

This a a full flued fire, outside stone fireplace chimney

 

[ElevatorGuy]

Never had an issue with mine outside, The cat when burning on my VC stove keeps the exhaust plenty hot. I’ve seen plenty of chimney fires in my fire department days. Brick chimneys are a completely different beast, Lots of mass to heat. They need to be lined.

 

[sean donato]

I have 2 class A insualted stainless chimneys, one on the house and one out in the shop. The one on the house is a through wall, sort of like the op, with 23' of triple wall insulated pipe out side of the house (dura vent brand), and the one in the shop, is a roof exit,(selkirk brand ) with ~10' of double wall insualted pipe, ~4' of it is through the roof, ~6 foot between the ceiling and roof, from the stove to the ceiling is stainless single wall. (Roughly another 8 feet of pipe.)
I actually have much better draft in the house with the insulated stainless chimney then I ever had with the old masonry chimney it replaced.
I've never had a build up, or condensation issue in the house, and I expect not to have any such issues in the shop either. (Fresh install, just started using it this burn season.) Neither has shown any symptoms of Condensation forming in the pipe. Usually a 300* flu temp is about as cold as I will burn, unless I'm letting the fire burn out. (Measired via an in pipe temp probe. Normal flu temp, varries from 300-500*f give or take a few degrees) I'd suspect a few things could be the issue, assuming it is indeed an Insulated class A chimney in use. First, he's just burning too cold. Second the wood is still wet. Either will cause clogging of the chimney, and/ or condensation. Clogging of the chimney will cause back draft like symptoms, but it's really a flow issue, not really a true back draft. The exhaust just doesn't have anywhere else to go, if the chimney has issues.

 

[ErnieG]

I appreciate all the info...let me answer some of the questions.
The outside is a class A double walled insulated pipe I believe its Selkirk brand pipe from Lowe's .
I cleaned the entire chimney just before lighting it this fall so I'm certain it's clean .
My wood was cut last winter and stacked under roof so its been drying for a year now .
Sometimes I do dampen it off to try and get a longer burn overnight or when I'm away at work for the day.
It may be that I'm damping it down to much and not getting the flue gas got enough to keep the entire chimney hot enough to keep a good draft going .
I'm thinking maybe a double walled pipe inside the garage would help keeping it hot enough before exiting the building .
Thanks again
Ernie

 

[Lee192233]

My wood was cut last winter and stacked under roof so its been drying for a year now.

I don't know your local area but around here if that was oak it wouldn't be ready to burn. Does it push water out of the ends when burning?

Sometimes I do dampen it off to try and get a longer burn overnight or when I'm away at work for the day.
It may be that I'm damping it down to much and not getting the flue gas got enough to keep the entire chimney hot enough to keep a good draft going .

A friend of mine plugged his chimney up in a month. He was new to wood burning so he was using wet wood and was damping it down too much. He had a 6" Class A also. I'd check the chimney, better safe than sorry.

 

[Mad Professor]

I just started burning wood with Mom and Grandma, ~1966. Grandma had a Glenwood I'd get going ~5AM for water tea/coffee and toast on the top, then stoke the fire on the heating stove that heated the home....

Uncles taught me how to split wood,.................

 

[nedsim]

You have quite a few joints in the un-insulated inside pipe. If they're sucking enough room air into the pipe, that may interfere with the draft. You can check with a burning splint or other smoke generator when the chimney is drawing well. Pay particular attention to the rotating joints in the adjustable elbows.

Furnace cement will seal the worst of the leaks. It's not a great solution, but will work well enough to tell whether the leaks are contributing to the problem.

 

[Sidecarflip]

If there is minimal temperature differential between the outside run of flue pipe and the ambient air, there will be minimal induced draft. How it works. Flue diameter also is important. If you have stinky moisture (condensation) running down the pipe inside, you have compromised pipe joints and they need to be sealed up and / or the stack temp needs to be higher.

On our pellet stoves (we have 2 actually), the vent pipe is double wall insulated with an air gap in between and the exhaust temp is much less than a wood burning appliance and that requires an air gap insulated double wall flue pipe. It's stainless (304 sheet) on the inside with an air gap (1/4") and a galvanized outer sheath and all the joint sections physically interlock as well.

 

[snobdds]

I think it might be as simple as the first fitting above the stove is bad. Those twist like fittings are notorious for leaking. Try to reconfigure the stove to only use straight and 90 bends.

 

[Del_]

 

[ErnieG]

View attachment 1225261

Yes it is upside-down..my stove starts out with a straight piece .
I can start with a small piece on the stove and turn around the next pipe to get the joints going the correct way .

Ernie

 

[Sidecarflip]

Keep in mind that every 90 degree elbow reduces draft by 1/3rd. In the case of our pellet stives, they have induced draft via a draft blower in each unit. It's computer controlled and only provides enough draft to burn the pellets, how they achieve 85% average efficiency. Computer controls everything, from fuel input to draft.
and neither produce any creosote, just dry ash.

Been roasting saw logs that no one seems to want, for the last 2 weeks straight, Almost have that licked and a huge pile of ash as well. Been raining here but has not dampened the fire at all.

This morning I went out and 'roused' the fire with my portable blower. Didn't take much to get it roaring again.

 

[ErnieG]

I think it might be as simple as the first fitting above the stove is bad. Those twist like fittings are notorious for leaking. Try to reconfigure the stove to only use straight and 90 bends.

Id like to reconfigure with only one elbow but I don't have the clearance from the wall to the back of the stove if I come straight out of the stove and up to an elbow so I have to have that second one to keep the clearance from the wall .

Ernie

 

[Sidecarflip]

When we lived in norther Ohio, many years ago, the house we owned had an Iron Fireman converted to natural gas, coal burning furnace that I retro fitted with shaker grates and rebuilt the coal bunker in the basement as well and heated with hard coal and wood from my arborist business. Nothing beats the heat from hard coal and free wood except we did have a chimney fire once and that was not good. No damage however but after that I kept the chimney clean, cleaned out the cleanout and never choked down the fire again. A starved for air fire makes creosote and creosote causes chimney fires and most times with bad results like burning down the house.

Not sure if you can get a chimney fire in a stove pipe but I imagine anything is possible.