BK Ashford vertical rise requirement (2-3 ft)

[tsh2002]

Hello:
We have been at the local dealer and I think we've decided on the BK Ashford 30. This is a new install, in a new home. I see it recommends a minimum of 2 ft vertical rise from the top of the stove to the bottom of the thimble and recommends 3 ft. In our case, the bottom of the thimble is only about 51 inches from the floor, so if I'm looking at this right the vertical rise would only be about 20 inches. I read other threads here on this and it sounds like this is only to ensure enough draft. In our case, the chimney is solid masonry on the inside of the home, with a non-insulated 6" stainless liner, and from the thimble to the top should be about 16 ft. We also plan on using an OAK and will be installing the stove as close as we can to the chimney using the minimum clearance of 6".

Could this cause any sort of issue since we are short of the 2-3 ft vertical rise requirement?

Thank you in advance.

 

[kennyp2339]

You should be in the ballpark of ok draft, make sure you use (2) 45 elbows vs single 90deg elbow, if draft is a minimum, you can add a anchor plate to the top of the chimney, then a 3ft section of class a pipe.

 

[tsh2002]

You should be in the ballpark of ok draft, make sure you use (2) 45 elbows vs single 90deg elbow, if draft is a minimum, you can add a anchor plate to the top of the chimney, then a 3ft section of class a pipe.

Thanks for this feedback. I saw the tip on using two 45s in the BK FAQs to fix any issues with low draft and smoking in to the room, too, so this makes sense. Good to know.

I've tried to reach BK via their website to confirm this from the vendor directly, too, however I haven't heard back in about a week there. I am hoping for an official answer from BK as well, before any sort of purchase.

 

[kennyp2339]

let me help you out... @BKVP

 

[BKVP]

I'd either relocate the entry point closer to the ceiling or consider other options. It is our experience that 24" can work, but 36" is usually a slam dunk. Of course you have a ss liner and interior wall masonry fireplace.

Explore relocating entry point costs....

BKVP

 

[tsh2002]

I'd either relocate the entry point closer to the ceiling or consider other options. It is our experience that 24" can work, but 36" is usually a slam dunk. Of course you have a ss liner and interior wall masonry fireplace.

Explore relocating entry point costs....

BKVP

Thanks for your input on this. Unfortunately, relocating the entry point is probably not a possible option for us, it's a fieldstone chimney and it would be very difficult to change it. Have you guys had any luck using the 45 degree elbows instead of the 90, when it's this close? As mentioned we would also be using an OAK (outside air kit) to hopefully improve the draft, too.

 

[BKVP]

Thanks for your input on this. Unfortunately, relocating the entry point is probably not a possible option for us, it's a fieldstone chimney and it would be very difficult to change it. Have you guys had any luck using the 45 degree elbows instead of the 90, when it's this close? As mentioned we would also be using an OAK (outside air kit) to hopefully improve the draft, too.

2 45's back to back is what we recommend in addition to the vertical rise requirement. Unfortunately you'll have 90 in the stack at the liner connection. F/A can help....

 

[tsh2002]

2 45's back to back is what we recommend in addition to the vertical rise requirement. Unfortunately you'll have 90 in the stack at the liner connection. F/A can help....

Thanks BKVP and kennyp2339. We do like this stove over the others we have been looking at. Hoping that with these shortcomings it will still perform well. Thanks for your help.

 

[Ashful]

Do note that the stove will run fine on less than ideal draft, I have one of mine on less than the recommended chimney. But it will limit how far you can turn it down without stalling, as extreme turn-down causes a lowering of chimney temperature, and thus a reduction in draft. It's a bit of a compound problem, if you follow the simple logic.

So, if you want to hit those 30+ hour burns you hear some of us discussing, you'll want to optimize your draft. But if you don't mind burning on a higher setting, perhaps equivalent to a 12 hour burn time, then the whole rig becomes exponentially less sensitive to optimizing draft.

 

[tsh2002]

Do note that the stove will run fine on less than ideal draft, I have one of mine on less than the recommended chimney. But it will limit how far you can turn it down without stalling, as extreme turn-down causes a lowering of chimney temperature, and thus a reduction in draft. It's a bit of a compound problem, if you follow the simple logic.

So, if you want to hit those 30+ hour burns you hear some of us discussing, you'll want to optimize your draft. But if you don't mind burning on a higher setting, perhaps equivalent to a 12 hour burn time, then the whole rig becomes exponentially less sensitive to optimizing draft.

Thank you for this reply, it does help us understand what we will/could be faced with. I do still like how flexible the BK Ashford is, even with all of these factors so I am fairly certain that's what we will go with.

Thank you again for the feedback on this.

 

[Ashful]

I should have also added that cold starts can be a little more of a challenge on warmer days, with a short pipe. Some of us have had to pre-warm shorter chimneys with burning newspaper or a hairdryer, to get draft flowing the right direction on warmer days. Once the stove is going, it warms the pipe sufficiently to increase draft in the proper direction.

Then there are the days you forget to check draft, load and light the stove, and have smoke pour out of the inlets for the first four minutes, until the chimney warms up enough to start drafting correctly. This is not unique to the Ashford, in fact that stove breathes very easily with the bypass open on cold starts, this particular issue would be the same with any stove on a short chimney.

I don't know how (or if) extra elbows affects draft reversal. I wouldn't think it should at all, that should be dependent on height alone, with the elbows being more a factor of reducing velocity for a given static draft. In other words, height = voltage, elbows = resistance, with current = voltage/resistance.

 

[tsh2002]

Just following up on this, that we ended up getting the BK Ashford 30 that the dealer talked us in to, with the slightly larger firebox than the 20. The dealer talked us in to the 30 to make sure we can heat the home as much as possible even in the coldest time of year. We just fired it up today for the first time, and are very happy with it. I am amazed at the thermostatic control. Once it gets going, you set it and let it do its thing. But at the same time, just adjusting the knob slightly, you can instantly see the fire change a little bit so it seems to be very precise. I ended up putting together two 45 degree elbows rather than a single 90 degree, to try and eliminate any flow issues since we only have about a 20 vertical rise to our thimble. So far, no issues at all and it's relatively mild right now in our area (40 degrees outside). Thanks again for all of the help on this forum!

 

[Ashful]

Just following up on this, that we ended up getting the BK Ashford 30 that the dealer talked us in to, with the slightly larger firebox than the 20. The dealer talked us in to the 30 to make sure we can heat the home as much as possible even in the coldest time of year. We just fired it up today for the first time, and are very happy with it. I am amazed at the thermostatic control. Once it gets going, you set it and let it do its thing. But at the same time, just adjusting the knob slightly, you can instantly see the fire change a little bit so it seems to be very precise. I ended up putting together two 45 degree elbows rather than a single 90 degree, to try and eliminate any flow issues since we only have about a 20 vertical rise to our thimble. So far, no issues at all and it's relatively mild right now in our area (40 degrees outside). Thanks again for all of the help on this forum!

Great news. One thing you'll want to do in these first days/weeks, is to find the lowest setting at which you can run without stalling it. For most of us with Ashfords, this is somewhere around 3:30 to 4:00 o'clock on the dial, with 6:00 being wide open throttle. Use a small triangle of masking or electrical tape to indicate this position, and move it around until you've nailed it down.

A "stall" is when the cat falls out of active range, while there's still appreciable wood left in the box. With a good setup, you should be able to achieve 30 - 36 hours of active cat operation.

 

[tsh2002]

Great news. One thing you'll want to do in these first days/weeks, is to find the lowest setting at which you can run without stalling it. For most of us with Ashfords, this is somewhere around 3:30 to 4:00 o'clock on the dial, with 6:00 being wide open throttle. Use a small triangle of masking or electrical tape to indicate this position, and move it around until you've nailed it down.

A "stall" is when the cat falls out of active range, while there's still appreciable wood left in the box. With a good setup, you should be able to achieve 30 - 36 hours of active cat operation.

That's right about where I found the sweet spot to be so far, I think, it's close to about 4:30 or so. One thing I'm trying to figure out is what the temperature marks are on the gauge at the top. It's been running right around the middle of the "active" area for the most part. Is each mark something like 100 degrees, perhaps? Just curious what the actual firebox temp is according to those marks.

 

[stoveliker]

Pics please
We enjoy seeing new installs...

The temperature you read in the top is not the temperature of the firebox but the temp of what the catalyst exhausts. No need to know as long as you know whether it is active (hot enough) or not.

 

[Ashful]

@stoveliker already nailed it, but for the curious, there have been a few past threads from folks swapping that BK cat probe with a Condar FlueGard probe to try to "calibrate" that BK scale. Experiments done by some forum member and captured in an earlier thread, maybe 7+ years ago, asserted the FlueGard and BK were identical. By their estimation, you could just look at the FlueGard dial and know the temperature of the BK probe by that.

Then more recently, I think @Highbeam disproved that, at least with the two probes he owned. As to why the disagreement exists, it could be that one manufacturer or the other changed their designs, or more likely, just the inherent inaccuracy of both, unit-to-unit.

 

[tsh2002]

Thank you for the info, this is very helpful. Yes I will definitely experiment with the control and burn times. We are only a couple days in to this but loving everything about this stove. I was originally worried about the draft as I originally posted but absolutely no issues whatsoever so far after a few complete burn cycles. We've been able to get it up and running exactly as the instruction book mentions and it just runs. Again, thanks to all on this forum for helping us get through this adventure. And that is also helpful on the temp, it was more of a curiosity.

Pics attached

 

[stoveliker]

Wow! Nice set.up!!

 

[Highbeam]

@stoveliker already nailed it, but for the curious, there have been a few past threads from folks swapping that BK cat probe with a Condar FlueGard probe to try to "calibrate" that BK scale. Experiments done by some forum member and captured in an earlier thread, maybe 7+ years ago, asserted the FlueGard and BK were identical. By their estimation, you could just look at the FlueGard dial and know the temperature of the BK probe by that.

Then more recently, I think @Highbeam disproved that, at least with the two probes he owned. As to why the disagreement exists, it could be that one manufacturer or the other changed their designs, or more likely, just the inherent inaccuracy of both, unit-to-unit.

Everybody that I remember reporting has claimed the condar cat meter has a different and tighter scale. Meaning it’s less likely to wrap the needle up past the top of the scale like you can so easily with a fresh cat on a bk cat meter.

Numbers are awesome!

 

[Ashful]

Everybody that I remember reporting has claimed the condar cat meter has a different and tighter scale. Meaning it’s less likely to wrap the needle up past the top of the scale like you can so easily with a fresh cat on a bk cat meter.

Numbers are awesome!

Hmm... when I'm not so busy, I'm going to have to go back and find that old thread. It must've been 2015 or thereabouts, but unless my memory is just totally making things up, there was a thread in which someone (@webby3650?) did some testing, and asserted the scales were the same. I remember it in part because it contrasted with what you found, much more recently.

I believe you if there have been others confirming your findings. I really don't read 95% of the threads on this forum anymore.

 

[webby3650]

Hmm... when I'm not so busy, I'm going to have to go back and find that old thread. It must've been 2015 or thereabouts, but unless my memory is just totally making things up, there was a thread in which someone (@webby3650?) did some testing, and asserted the scales were the same. I remember it in part because it contrasted with what you found, much more recently.

I believe you if there have been others confirming your findings. I really don't read 95% of the threads on this forum anymore.

Don’t think it was me. I don’t really get too caught up in temps. I just learn the stove and run it at a comfortable pace for the space it’s in.

 

[tsh2002]

Great news. One thing you'll want to do in these first days/weeks, is to find the lowest setting at which you can run without stalling it. For most of us with Ashfords, this is somewhere around 3:30 to 4:00 o'clock on the dial, with 6:00 being wide open throttle. Use a small triangle of masking or electrical tape to indicate this position, and move it around until you've nailed it down.

A "stall" is when the cat falls out of active range, while there's still appreciable wood left in the box. With a good setup, you should be able to achieve 30 - 36 hours of active cat operation.

One thing I just discovered, is how much difference there is in burn time with little to no ash on the bottom vs. having a nice bed of ash. I think I was going overboard emptying it out at first. I (not intentionally) noticed a huge increase in burn time after allowing the ash bed to build up a little bit, currently have about a half inch bed and made a big difference in my experience. Seems like it doesn't produce much ash to begin with, burning mostly cherry/elm/ash. Now I'm able to get the dial down to 3:00-3:30 and nice burn times.

 

[Highbeam]

Good to leave an inch of ash to keep the clinkers from sticking to and damaging the bricks too.