Blaze King Ashford 30 BackPuffing

Long time reader, first time poster.

Switched out an old Vermont Castings Vigilant to a BK Ashford 30 last year to heat our 1,500 sq.ft. house.

Burn times and heat output with the BK is a huge improvement, but...

When we open the door to light/reload, we always get a little backpuffing. Not substantial, but you can always smell smoke in the room where the stove is afterwards. I'm following all the mfg's directions, opening the door super slowly, cracking a nearby window, but still having issues. Never had an issue with smoke odor from the Vigilant.

Wondering if the backpuffing is due to a bad draft because of an oversized flue. When I swapped the Vigilant for the BK, we replaced the 8" stovepipe with 6", but left the 8" diameter chimney pipe in place, and used a reducer/expander coupling to go from 6" to 8".

Any other suggestions or ideas would be greatly appreciated. Thanks!

 

That sounds like smoke roll-out, not a back-puff, where the door is closed and smoke in the box ignites suddenly, forcing smoke out of the box or connector pipe into the room. The BKs need good draft. How tall is your flue, and what is its configuration (elbows, etc?) I'm not a chimney expert, but it may be possible to run 6" inside of the 8", or just go ahead and remove the 8" and replace with 6".

 

Have you called BK? I think this was an issue on some of these stoves...if you do a google search you will come up with some pretty longs threads on the subject. That 8" flue isn't helping the issue I'm sure...might want to pull a 6" liner in.
Oh, and welcome to FHC!

 

I think you're right Woody Stover. No elbows in the flue and the flue is about 15' total. I'd rather not replace the chimney pipe b/c that's a substantial cost. I could probably fit a liner inside the chimney.

 

Bet the BK isn't happy with the 8". You could try pulling the cap and adding a section of cheap snap together single wall to see if just adding more 8" would cure your issue. Assuming you are opening the bypass and twisting the stat wide open for a bit before opening the door?

 

Yup, doing that. I'm going to try to leave the door cracked for a bit, wait until the flue temp comes up, then open the door to load. Thanks again for the help.

 

Damper is definitely open. I made that mistake once in the bleary-eyed early AM once.

Wood is dry, I don't typically re-split and check with a meter, but I don't burn anything more than 15%.

 

I'll take a peek at the damper to make sure it's clear, but I'm confident it is. Cleaned 'er this year and went hog-wild with the shopvac inside the stove. This also happened when the stove/stovepipe was brand new.

No other fans on.

I do radon mitigation, so have experience with differential pressures in buildings, it's amazing how much vacuum a range hood will pull.

 

Straight up is good but 15' is marginal for an Ashford. You'll need to upgrade, I fear..

 

I was thinking that would be a potential solution. It's class a, extends 2' above the roofline.

 

I might try 6" first, depending on your priorities. Cheaper and easier to just slap another section of 8" chimney on, but it may not look as nice with more chimney up there. Also, the BK can run with low flue temps, so keeping flue gas temp up is a priority to keep the chimney cleaner. 8" hurts you there. Area of 6" is 28 sq.in, 8" is 50, but I'm not sure how that would equate to actual percentage of draft lost. Is your cap above the ridge, or just 2' above the roofline? If the cap is lower than the ridge, on the leeward side of prevailing winds, wind could push down at certain times, complicating things..

 

So to be clear, the spillage and smoke smell are related to opening door to start or refuel the fire?

If this is correct, do you have a F/A connection?

Is the black stove pipe double wall or single wall?

Please address these questions and we can go from there...

 

What's that?

 

Fresh air connection also known as an OAK.