Over burning/over draft

[Inthewoods2019]

I think his previous stoves were old smoke-bombers that you could cut the air on, any time you wanted. I guess I should shut up and let him answer.

Yes sorry to disappoint your assumptions...But we had a 2017 JA Roby Cuisiniere wood cook stove. Ranked highest EP for a cook stove on the market.
Must say we had no problem with the burn and it responded well and was good on wood.
But the oven was not designed properly and very very inefficient.

 

[thechimneysweep]

The draft test read around 1.2 -1.3 if I remember correctly.

Inthewoods, I agree with your local tech that the problem you experienced was due to excessive chimney draft. PE says the optimal draft for the 2020 LE model is the same as the 2019 Super Series models, 0.04 water column. During EPA testing, the test flue developed updrafts as low as 0.011 (sustained burn) and as high as 0.089 (draft control wide open at startup). An updraft of 1.2 to 1.3 wc is simply off the charts.

The main modification PE made to the Super firebox to meet 2020 standards was to replace the linkage which controlled the air supply to the secondary fire with their patented EBT2 device, previously used with great results in the Summit/T6 and Neo fireboxes. The EBT2 is designed to open up when chimney updraft increases during stage 2 of the burn, as described on our website at (broken link removed).

So, your Super LE model has three sources for incoming combustion air: the primary draft control, the boost air pipe and the EBT2. You have some control of the primary air control, but the other two are balanced to supply the proper amount of air to the fire when chimney updraft is in the 0.04 wc range, with a maximum of 0.09 wc.

At 1.2 - 1.3 wc, your chimney is vacuuming an excessive amount of air through the uncontrolled boost air and EBT ports, even when your primary air control is turned to low. I might have tried a 5" rain cap, to reduce the updraft, but your tech's solution of blocking the boost air intake seems a reasonable solution (with your extreme updraft, you're not likely to ever need boost air).

 

[bholler]

The draft test read around 1.2 -1.3 if I remember correctly.

Inthewoods, I agree with your local tech that the problem you experienced was due to excessive chimney draft. PE says the optimal draft for the 2020 LE model is the same as the 2019 Super Series models, 0.04 water column. During EPA testing, the test flue developed updrafts as low as 0.011 (sustained burn) and as high as 0.089 (draft control wide open at startup). An updraft of 1.2 to 1.3 wc is simply off the charts.

The main modification PE made to the Super firebox to meet 2020 standards was to replace the linkage which controlled the air supply to the secondary fire with their patented EBT2 device, previously used with great results in the Summit/T6 and Neo fireboxes. The EBT2 is designed to open up when chimney updraft increases during stage 2 of the burn, as described on our website at (broken link removed).

So, your Super LE model has three sources for incoming combustion air: the primary draft control, the boost air pipe and the EBT2. You have some control of the primary air control, but the other two are balanced to supply the proper amount of air to the fire when chimney updraft is in the 0.04 wc range, with a maximum of 0.09 wc.

At 1.2 - 1.3 wc, your chimney is vacuuming an excessive amount of air through the uncontrolled boost air and EBT ports, even when your primary air control is turned to low. I might have tried a 5" rain cap, to reduce the updraft, but your tech's solution of blocking the boost air intake seems a reasonable solution (with your extreme updraft, you're not likely to ever need boost air).

I am pretty sure it had to be .12 or .13. I have tested draft on lots of chimneys some as high as 40 feet and never got anywhere near 1 wc. I agree blocking boost air will help but I personally find reducing draft is a better solution.

 

[Highbeam]

At only 16’ of chimney, do you think the measured draft was actually 0.12”? That’s still above spec but more reasonable.

 

[bholler]

At only 16’ of chimney, do you think the measured draft was actually 0.12”? That’s still above spec but more reasonable.

Yes I agree.

 

[thechimneysweep]

I agree too. Was going to make that point in my posting above, but it was already getting pretty wordy. Plus, I'm lazy. And even 0.12 wc is off the charts.

 

[Inthewoods2019]

Yes I agree.

What your missing is that the tech put a flue damper in and it made no difference in the draft test. So would that not show that it was not a chimney issue?

 

[Inthewoods2019]

I agree too. Was going to make that point in my posting above, but it was already getting pretty wordy. Plus, I'm lazy. And even 0.12 wc is off the charts.

So after he tapped the air boost it was.8
But before tapping it and after he put the damper in the flue it was around either.12-.13 or1.2-1.3?? But he said it was too high and should be between.4 - .8 Does that make sense? We were trying to stay out of his way and since he was on the phone a lot to his boss and the sales rep we didn’t get to ask much.
All we know is it is working good now with a large bolt in the hole cutting most of the air.
We took the tape off to take pictures and replaced it with a bolt. Seems fine now.
So we can only conclude it was getting too much air from the boost hole otherwise the flue damper would have shown a difference.

 

[bholler]

What your missing is that the tech put a flue damper in and it made no difference in the draft test. So would that not show that it was not a chimney issue?

No i am not missing that at all. It is just that it makes no sense at all. How could cutting down the flue volume by 2/3 not change how the stove operates.

 

[bholler]

So after he tapped the air boost it was.8
But before tapping it and after he put the damper in the flue it was around either.12-.13 or1.2-1.3?? But he said it was too high and should be between.4 - .8 Does that make sense? We were trying to stay out of his way and since he was on the phone a lot to his boss and the sales rep we didn’t get to ask much.
All we know is it is working good now with a large bolt in the hole cutting most of the air.
We took the tape off to take pictures and replaced it with a bolt. Seems fine now.
So we can only conclude it was getting too much air from the boost hole otherwise the flue damper would have shown a difference.

.04 to .08 would make sense and is within spec .3 is the highest draft i have ever measured on a natural draft chimney that was about 40 feet tall. So i find it hard to beleive he tested anything higher than that on your normal height chimney. I am not saying you are wrong he may just have said it wrong. If blocking the hole works great. It is just that in my experience it works much better to limit the draft of the chimney than restricting the air. The reason for this is if you still have that strong draft any small leak like a door latch that needs adjustment can cause a big problem quickly. Sometimes it is the only option though and in those cases you really need to be ontop of the maintenance.

 

[Inthewoods2019]

No i am not missing that at all. It is just that it makes no sense at all. How could cutting down the flue volume by 2/3 not change how the stove operates.

We take it means that the stove was still receiving too much air from the air boost and that the chimney was not the draft issue at all.
I don’t know not our line of knowledge but was hoping someone would understand it.
Since they want to hit us up with a bill... They spent two days here trying to find fault with the chimney and in the end plugged the air boost hole and it worked???
So is it the stove or the chimney?

 

[bholler]

We take it means that the stove was still receiving too much air from the air boost and that the chimney was not the draft issue at all.
I don’t know not our line of knowledge but was hoping someone would understand it.
Since they want to hit us up with a bill... They spent two days here trying to find fault with the chimney and in the end plugged the air boost hole and it worked???
So is it the stove or the chimney?

It is the chimney pulling to much vacuum on the stove. I am not saying you should have to pay the bill you hired them to install the stove in a way that it works it is their responsibility to do that. Sometimes we need to eat a loss on a job to keep the customer happy and maintain our reputation.

But yes from what i am hearing the chimney is pulling to much draft for the stove. So it is a problem with the chimney.

Ultimately it will come down to the wording of the contract to determine if you are on the hook for the bill legally

 

[therealdbeau]

Sounds like you got it figured out. The bill you received aside, I think that stoves aren't quite an exact science and take a bit of sorting out after install. I think they are designed in a lab and only account for limited circumstances. Not to mention they are required to conform to federal regulations regarding pollution output.

Like I said before, my stove required significant modifications to simply not overfire and glow red. I didn't bother calling the service provider because I'm just not that type of person and am willing and able to take matters in my own hands. Also I don't exactly believe that the jokers that installed my stove had the wherewithal to figure it out, much like you.

All that said, I wouldn't pay the bill. I know not everyone is naturally confrontational and sometimes you have to take a kick in the nuts and chock it up as a learning experience. But if you have a stubborn bone in your body give them a calm sturn talking to about how you feel and hopefully they are reasonable and see your side. Good luck.

 

[bholler]

Sounds like you got it figured out. The bill you received aside, I think that stoves aren't quite an exact science and take a bit of sorting out after install. I think they are designed in a lab and only account for limited circumstances. Not to mention they are required to conform to federal regulations regarding pollution output.

Like I said before, my stove required significant modifications to simply not overfire and glow red. I didn't bother calling the service provider because I'm just not that type of person and am willing and able to take matters in my own hands. Also I don't exactly believe that the jokers that installed my stove had the wherewithal to figure it out, much like you.

All that said, I wouldn't pay the bill. I know not everyone is naturally confrontational and sometimes you have to take a kick in the nuts and chock it up as a learning experience. But if you have a stubborn bone in your body give them a calm sturn talking to about how you feel and hopefully they are reasonable and see your side. Good luck.

What stove do you have? What height is your chimney?

I agree they probably shouldn't have to pay it. But we also don't know the circumstances or the terms of the agreement. If it was stated they were only responsible for hooking it up and nothing more they should not have to eat all of that labor.

 

[therealdbeau]

What stove do you have? What height is your chimney?

I agree they probably shouldn't have to pay it. But we also don't know the circumstances or the terms of the agreement. If it was stated they were only responsible for hooking it up and nothing more they should not have to eat all of that labor.

VC Merrimack insert, 17ft chimny. Admittedly very different from the OP's regular stove.

Yes, it all comes down to the service agreement. And honestly it sounds like the OP isn't necessarily having a malfunctioning stove as he never said it was glowing just that it's running hotter than he would like. But it's not operating how he would like and sometimes you have to figure that out on your own in my opinion.

Actually I may retract my statement that he shouldn't have to pay because again his stove isn't really malfunctioning just that it's not operating how he would like it to. It's a grey area really but there's nothing wrong with having a civil conversation with the service provider.

Now that I think more about it, the tech did infact solve the problem by taping the boost air hole so maybe they should be paid for that. However, as a business owner sometimes a little time and effort to make sure the customer is happy is a cost of business that should be considered a write off.

 

[bholler]

VC Merrimack insert, 17ft chimny. Admittedly very different from the OP's regular stove.

Yes, it all comes down to the service agreement. And honestly it sounds like the OP isn't necessarily having a malfunctioning stove as he never said it was glowing just that it's running hotter than he would like. But it's not operating how he would like and sometimes you have to figure that out on your own in my opinion.

Actually I may retract my statement that he shouldn't have to pay because again his stove isn't really malfunctioning just that it's not operating how he would like it to. It's a grey area really but there's nothing wrong with having a civil conversation with the service provider.

Now that I think more about it, the tech did infact solve the problem by taping the boost air hole so maybe they should be paid for that. However, as a business owner sometimes a little time and effort to make sure the customer is happy is a cost of business that should be considered a write off.

I agree completely a civil conversation could go a long way.

I am surprised you had issues with your Merrimack. Most people have been very happy with them. What did you do to address the problem?

 

[SpaceBus]

Yes sorry to disappoint your assumptions...But we had a 2017 JA Roby Cuisiniere wood cook stove. Ranked highest EP for a cook stove on the market.
Must say we had no problem with the burn and it responded well and was good on wood.
But the oven was not designed properly and very very inefficient.

I had looked at the JA Roby cookers, but no option for DHW. Good to know it wasn't a big loss.

 

[therealdbeau]

I don't want to sidetrack the OPs thread here but my situation is mostly documented here -
https://www.hearth.com/talk/threads/vermont-castings-merrimack-montpelier.173427/page-3#post-2349193

It is a great stove just needed a little tweaking for my situation

 

[begreen]

It's a bit unusual to have draft issues with a 16' flue so I can understand why the installer did not perceive this to be an issue initially.

 

[bholler]

It's a bit unusual to have draft issues with a 16' flue so I can understand why the installer did not perceive this to be an issue initially.

I agree completely.

 

[Woody Stover]

What your missing is that the tech put a flue damper in and it made no difference in the draft test. So would that not show that it was not a chimney issue?

I didn't notice a big difference at my SIL's when I put in a flue damper, but she has 21'. A second damper would probably make a bigger difference.

 

[begreen]

I tried a stack damper on our stove when the F400 was installed. It made secondary burn poorer. I removed it. Hasn't been back on since then.

 

[Woody Stover]

I tried a stack damper on our stove when the F400 was installed. It made secondary burn poorer. I removed it. Hasn't been back on since then.

That particular stove wants a lot of draft though, correct?

 

[begreen]

With 20ft of straight up flue it had it.

 

[Woody Stover]

With 20ft of straight up flue it had it.

Did the damper seem to affect both the log flame and secondary equally?