Draft Testing Question (re: backpuffing problem)

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pdxdave said:
So with it being so rare, why is chimney always the #2 go-to solution anytime someone comes along with a wood-burning issue ?
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Because the chimney often isn't up to par with the requirements of a modern stove. The fix is usually obvious, not draft measurement is needed. The stove manufacturers will state what they require in the manual, experience will tell you if it needs to be even taller due to elbows in the system or other structural issues around the home.
With this particular situation, a draft test is needed though.
 
So the dealer came out and measured the draft. Ideally he would have measured from 24 inches over the stove but since I didn't want an extra hole in the pipe, he used the hole for the flue probe, which was 18 inches over the stove. It read anywhere from .3 to .7 with the stove cold. When I turned on the exhaust fan over the kitchen range, it appeared to go way up to 1.7 or so. I asked if that could be a reverse flow and was told it could be. So we got hold of Chris (BKVP) at Blaze King. He suggested running a blow torch inside the box and seeing if the number rises or falls.

When we opened the front door of the stove (with the range fan off), the measurement jumped way up. Then, with the torch running, it went higher, confirming that the flow was up and out of the house.

The dealer said that, on an overcast day, when the barometric pressure is low, the draft could be much weaker. But it was a warm day so it would also be stronger if the weather was colder.

They inspected the stove. The cat looked fine but they found that the source of the leak might be that the door gasket was hitting near the edge on the left side (closest to the hinge). Chris was still on the phone. He ran out to the warehouse to find out if the door could be adjusted on the Ashford. It turned out that the whole front panel could be moved. So he instructed them on how to do that.

Once the stove was adjusted we lit a fire. There was almost no wood smoke smell. Just a tiny bit near one corner of the door. Chris, who had already offered to replace the stove, said he'd be happy to try replacing the door gasket and the cat to see if that fixes it. The dealer is also going to adjust the bypass door since I'm still getting constant smoke up the chimney. Lastly we're going to get a bit of dry cord wood so we can test it with something dry that's not a pressed log.

The house has been much cleaner since then. There's no wood smoke smell at the top of the stairs or in the bathroom behind the stove for the first time. I still want to resolve the remaining issues but it seems like it may be possible. If these fixes don't work, Chris will still be willing to swap out the stove. Both the dealer and Chris made clear I could have a new stove if I want one, but I'd prefer not to waste a perfectly good stove if it can be made to run right.

Can't tell you how much I appreciate both the dealer (who has gone above and beyond to make things work right) and Blaze King, which is committed to customer satisfaction. Both have won my loyalty. If anyone were buying a stove, I would say you can't go wrong with these guys.
 
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I told you that they would make it right! You won't find a better company to work with, Blaze King is top notch!
 
Considering how mild our temps have been this is great news. I am still confused at the range fan reading, but smoke-free is great.
 
I would imagine the range fan was pulling a bunch of air down the chimney into the stove. What else could it be?
 
webby3650 said:
I told you that they would make it right! You won't find a better company to work with, Blaze King is top notch!
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Thanks for your recommendation. But for you, I probably would have bought the Lopi and, as I discovered upon calling them, their idea of customer service is to deny problems and blow smoke in your eyes.
 
What I don't understand are the numbers. If normal draft was .3 to .7, how would introducing negative pressure via the range fan, increase the number? I would expect it to reduce that number. That is unless the draft numbers were -.3 to -.7.
 
Yes, that would make more sense. If correct it indicates the need for makeup air to counteract the effect of the range fan.
 
I don't like the idea of the range hood competing with the wood stove air. Is there an HRV in the structure?
 
Are you getting a big puff that puts the smoke in the room?
I know it can happen when the gas's build up then all of a sudden they are ignited.
It's my understanding that is usually caused by a stalled or very slow draft.
But I guess you already know that probably.
 
Well, I may have spoken too soon. It's raining tonight. Returned home to find the house pretty smoky. It's possible my wife spilled it during a reload. Or it could be the lower barometric pressure is causing reduced draft. Either way we've got to replace that door gasket. If that doesn't solve the problem, I'll take BKVP up on the offer for a new stove. We've got to fix this.
 
Those draft numbers don't make any sense to me.

I would expect to see hardly any draft with the stove cold.

Then by turning a vent fan on expect to see it get pulled just a bit to the decreased draft side - or not affect it all, ideally.

Then lighting a fire or doing the torch thing in the box, expect to see increased draft.

But just the numbers themselves seem whacked too. My 30' chimney pulls 0.1" draft with a fire going in my boiler. Big wind gusts with the baro damper held shut can spike it to 0.3". No fire going & no wind = zero. So the numbers stated above seem very odd. 1.7 with the range fan on?

If you really want to fix it & stay on top of it, get your own manometer & temporarily permantly mount it (ha) so you can see what the draft is at all times.
 
That's an interesting idea. Do they have units designed to be kept installed, sort of like the flue temp probe?
 
Tenn Dave said:
Absolutely. As I have posted several times before, my PH had a smoke smell issue and I had and still have great draft. The problem turned out to be a flawed door gasket design and a syphon effect in the door hinge channel that was pulling smoke from the stove into the room. The WS repair kit fixed both problems. And that is a fact, not a theory. No more smoke. :)
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I'm still trying to get my head around the physics behind this "syphon effect". I had the smoke smell in my Progress and decided to make changes one step at a time. I replaced the door gasket and the door frame mounting bolts that came in the WS repair kit, but DID NOT add the hinge channel.

The smoke smell has been gone all year. I know they tested the channel and claim it helps, but I just don't see how it matters, since the door gasket separates the firebox from the Hinge channel.

Too bad Parallax's door fix was not the whole problem but hopefully closer to a solution.
 
maple1 said:
Those draft numbers don't make any sense to me.

I would expect to see hardly any draft with the stove cold.

Then by turning a vent fan on expect to see it get pulled just a bit to the decreased draft side - or not affect it all, ideally.

Then lighting a fire or doing the torch thing in the box, expect to see increased draft.

But just the numbers themselves seem whacked too. My 30' chimney pulls 0.1" draft with a fire going in my boiler. Big wind gusts with the baro damper held shut can spike it to 0.3". No fire going & no wind = zero. So the numbers stated above seem very odd. 1.7 with the range fan on?

If you really want to fix it & stay on top of it, get your own manometer & temporarily permantly mount it (ha) so you can see what the draft is at all times.
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I thought it was just me, but those results make no sense to me either. I have a Dwyer Mark II model 25 manometer that I have permanently mounted on the wall next to my furnace, my readings mimic maples, only a bit lower (less draft). Those Dwyers can be had on ebay for $20-$30 BTW.
I assume the .3 to .7 and 1.7 readings you referenced are actually negative draft #s and should be written -.03" WC to -.07" WC and -.17" WC (WC stands for water column as in inches of water column, a common measurement for "vacuum", or negative pressure)
I makes no sense to have more draft with the range fan on. I thought at first that maybe the dealer had the manometer hooked up backwards but then when you added heat (torch) the draft increased as it should have.

Parallax said:
It read anywhere from .3 to .7 with the stove cold
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Mine reads zero when cold.

Parallax said:
When I turned on the exhaust fan over the kitchen range, it appeared to go way up to 1.7
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I would think it would have dropped if anything

Parallax said:
When we opened the front door of the stove (with the range fan off), the measurement jumped way up.
Click to expand...
My draft drops when I open the door

Parallax said:
Then, with the torch running, it went higher, confirming that the flow was up and out of the house.
Click to expand...
This part sounds correct
 
Hmm... maybe I should get a manometer on my pipes before those Ashfords come in! I had also noticed the numbers in the manual, but figured, "surely they can't be THAT picky." This is the first I've heard of drafting troubles with an Ashford.

I had pretty much decided I was done burning for the year, as there's presently a swamp between the stoves and the wood supply... or more accurately, there is yard that will become swamp, should the tractor try to cross it with a load of wood.
 
Joful said:
Hmm... maybe I should get a manometer on my pipes before those Ashfords come in! I had also noticed the numbers in the manual, but figured, "surely they can't be THAT picky." This is the first I've heard of drafting troubles with an Ashford.

I had pretty much decided I was done burning for the year, as there's presently a swamp between the stoves and the wood supply... or more accurately, there is yard that will become swamp, should the tractor try to cross it with a load of wood.
Click to expand...
They aren't THAT picky. This is an extreme example.
 
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