New house, back draft question

[djlew]

Wow, never thought I would see myself on the cat stove side of hearth! All jokes aside, brother and sister-in-law just bought a new house that came with a stove. Definitely a Hearthstone stove, but not sure about model. Maybe some type of Green Mountain I thought?

Anyway, we went to light an inaugural fire today and instantly got hit with a massive back draft. I'm new to cat stoves, but I figured the cat needed to be inactive and the air open when lighting. Once the cat got to to the silver area of the cat thermostat, engage. Then just adjust the air intake as necessary.

I attached some pics of the setup. Please let me know if more would be helpful. The stove got hot, smoke was exiting the stack pretty well, but no matter when we tried to reload, BOOM back draft.

Stove was apparently rarely used. My immediate thought was a combo of quality of wood and inspection of the flue. I still recommend that, but is there anything else we could be missing? Just wanted to get some opinions from folks who have the same stove.

Thanks again all!

 

[begreen]

Did something change that created negative pressure in that area? This could be a kitchen or bath exhaust fan, clothes dryer, gas/oil HW heater, furnace or boiler starting up.
Next time if it happens, open a nearby window 1/2" to see if that cures the problem.If so, an outside air supply (OAK) may be needed.

 

[djlew]

Did something change that created negative pressure in that area? This could be a kitchen or bath exhaust fan, clothes dryer, gas/oil HW heater, furnace or boiler starting up.
Next time if it happens, open a nearby window 1/2" to see if that cures the problem.If so, an outside air supply (OAK) may be needed.

Thanks for your input! We did open a nearby window. As the stove heated up, seemed to help, but not cure the issue. Worth investigating whether or not there was something else causing a negative pressure issue around but I don't think there was anything going at the time. I'll dig a bit more. I thought maybe 2 90 degree elbows could cause a bit of difficulty creating a draft if they are a bit dirty, but want to make sure I'm not missing anything obvious. That chimney stack looked a bit wonkey to me too.

Thanks again!

 

[begreen]

The two 90º turns in the flue don't help when the draft is marginal. Is the chimney on a one story section of a 2 story house?

 

[djlew]

It's a one story house, but I did wonder if the chimney was properly sized. Looked like that 90 in the pics, into another 90 or I guess a Tee because there is a cleanout on the other side outside in the driveway. Then just a chimney chase up to the top there most of the way. I should be over there soon to take more of a closer look. Considering my inexperience with stoves in general but especially cat stoves, I want to make sure I'm not missing anything obvious to somebody else!

Thanks again!

 

[begreen]

Each 90º turn is like removing 2 ft of flue height. The chimney looks to be on the short side already and this stove likes at least 16' of flue, straight up.

 

[djlew]

Doubt that this setup is sized properly, I think you're right. Especially after taking a look again going over this past weekend. As a more permanent solution, I guess recommendation a reevaluation of the flue system is in order, but maybe an OAK can help out in the meantime? Made sure no other factors were in play (forced air systems, etc. kicking on), and of course the window crack trick, and not much help there but a tad better.

Will definitely research the OAK. I assume with these stoves the OAK adapters are model specific? (I at least know this is a Hearthstone stove, thanks to the gigantic branding!) I am fairly confident this is some sort of Green Mountain, but there was no documentation or anything left on the stove when the house was purchased.

Thanks again, really appreciate the expertise on this. The family got a kick out of my time on here, but they are definitely loving the advice!

 

[RockyMtnGriz]

I'd try a temporary extension on the top of the stack and see if it helped. I also don't see where you confirmed the flue was reasonably clean, maybe I missed it, but that should be the first thing.

 

[djlew]

I'd try a temporary extension on the top of the stack and see if it helped. I also don't see where you confirmed the flue was reasonably clean, maybe I missed it, but that should be the first thing.

Extension, definitely something to look into. Chimney inspection and sweep is DEFINITELY on the list. Really wanted to gather as much information as possible about these stoves and this type of setup just to get a full picture. That way having a game plan and some options. I appreciate your feedback! I did wonder if what was on top there outside of the chase in the pic in my original post was an extension... kind of looked like one, but not sure. Maybe hard to say without a better look.

 

[GM80NY]

Definitely a Green Mountain!

Heres a few simple things.

Are you opening the bypass door (lever towards the floor) and fully opening the air control and cracking the door and keeping it there for 30 sec to a minute before fully opening? And opening the door slowly?

If the wood in there is not in the coal stage and the draft is poor you will get little puffs.

My technique is getting better. Also when reloading if your draft is poor and you put something that takes a lot of space quickly in the firebox it may cause some smoke to spill out the front.

98% of the time now I can reload and if any smoke comes out its the toasted wood smell that can actually be pleasant.

 

[djlew]

Definitely a Green Mountain!

Heres a few simple things.

Are you opening the bypass door (lever towards the floor) and fully opening the air control and cracking the door and keeping it there for 30 sec to a minute before fully opening? And opening the door slowly?

If the wood in there is not in the coal stage and the draft is poor you will get little puffs.

My technique is getting better. Also when reloading if your draft is poor and you put something that takes a lot of space quickly in the firebox it may cause some smoke to spill out the front.

98% of the time now I can reload and if any smoke comes out its the toasted wood smell that can actually be pleasant.

Thanks for your comment! I figured it was a Green Mountain 40 or 60, probably 40? It doesn't seem too large. I'm familiar enough with draft issues from my own stove, but this seems excessive with theirs. I would go as far as to say it's way more than just puffs of smoke, more a spill out. Regardless of burn stage. We had a nice fire going and if you open the door, BOOM smoke is piling out.

My immediate recommendation to them was obviously get the flue inspected and cleaned. The company I am dealing with now for an issue I am having is a perfect fit for them so I am excited to get them out there to take a look at their setup. I have a feeling there are some adjustments they would recommend.

Our attempts really have been verifying the bypass is open fully and the cat is disengaged. Light the fire, get a nice one going (door is closed at this point, because smoke would be piling out), quickly reload before more smoke piles out until cat thermostat is in the gray for active and then engage it and keep cooking. Every reload following smoke really piles out the same as starting the fire. That's really the part that gets me. Even with windows cracked and no other issues seemingly causing a bad draft other than 2 90 degree elbows up to the top of the chimney.

 

[GM80NY]

Ive got 2 90s on my chimney as well with 2 45s after to get around an eve. With mine I can never open the doors while wood is on fire and not have smoke escape. Ive only heard a few people on here with GMs say they can open the door while wood is burning and not have smoke spill out. This is mainly an issue for me in the beginning of the burn. I dont really open it to reload until its mostly coals. You might have to alter your expectations. I agree to have inspections done first.

My chimney is 8” since I have the 80.

 

[djlew]

Ive got 2 90s on my chimney as well with 2 45s after to get around an eve. With mine I can never open the doors while wood is on fire and not have smoke escape. Ive only heard a few people on here with GMs say they can open the door while wood is burning and not have smoke spill out. This is mainly an issue for me in the beginning of the burn. I dont really open it to reload until its mostly coals. You might have to alter your expectations. I agree to have inspections done first.

My chimney is 8” since I have the 80.

That's fair, thanks for your input. It is reassuring to have others weigh in with their experiences with similar stoves. I appreciate that. I think at least we have a plan, and that's a good thing. Will keep you all posted!