Mating an 8" Econoburn flue port to a 6" chimney flue...

[Loki]

I'm looking at the Econoburn 150 which has an 8" flue port. The existing connection on the chimney is 6". That port goes into the narrow side of a rectangular chimney tile. I know an adapter will shim the 8" pipe to 6" but I wonder about the risks I run.

Any advice, guidance, admonishments are appreciated.

 

[jebatty]

If the mfr spec 8", I think I would go with 8". You are likely to get insufficient draft if you go with less than spec'd. If insufficient draft is the result, neither you nor the stove will be happy.

 

[antknee2]

If your chimney is properly built for solid fuel , and inspected by a pro , located on inside walls of your house an capable of maintaining a negative draft of .02''min and .05'' max w.c. , at all times and conditions it should work fine in my opinion . Also Econoburn recommends that a draft regulator be used to prevent excess draft which could lead to boiler over firing . Anthony

 

[mtnmizer]

If your chimney is properly built for solid fuel , and inspected by a pro , located on inside walls of your house an capable of maintaining a negative draft of .02''min and .05'' max w.c. , at all times and conditions it should work fine in my opinion . Also Econoburn recommends that a draft regulator be used to prevent excess draft which could lead to boiler over firing . Anthony

Could you elaborate more on the draft requirements quoted? Is there some instrumentation to gauge the draft ect?
Thanks. MM

 

[pybyr]

I'm interested in more, Anthony, also, on the Econoburn recommendation for a draft regulator. My boiler has not arrived yet, but the dealer that I am getting it through was good enough to give me a full install/ operation manual for one when I was at the decision stage. I didn't notice anything about a barometric damper- is this something you picked up in conversations with the personnel at Econoburn. Eager to know more so that I can factor it in during the upcoming install

 

[mtnmizer]

I'm interested in more, Anthony, also, on the Econoburn recommendation for a draft regulator. My boiler has not arrived yet, but the dealer that I am getting it through was good enough to give me a full install/ operation manual for one when I was at the decision stage. I didn't notice anything about a barometric damper- is this something you picked up in conversations with the personnel at Econoburn. Eager to know more so that I can factor it in during the upcoming install

It's on page 8, "To maintain this draft one or two draft regulators may be required"

I spoke with the Dan at the factory and found him to be very helpfull. As I understand it,
pipe out from the boiler a short length into a tee with the draft regulator at the bottom..
as found on a gas appliance. Seemed odd to me but was assured it's ok. It's a spring loaded
door and can be obtained at a HVAC shop. MM

 

[Eric Johnson]

If the mfr spec 8", I think I would go with 8". You are likely to get insufficient draft if you go with less than spec'd. If insufficient draft is the result, neither you nor the stove will be happy.

That would normally be true, Jim, but as I recall from a past discussion, all Econoburn boilers have 8" chimney outlets, but the smaller units can do fine with 6" according to the factory and heaterman, who is a dealer. According to heaterman, all the company has to do is state in the manual that certain models can be fitted to a 6" chimney in order for it to be legal/code complaint to go with the smaller diameter.

 

[Loki]

If the mfr spec 8", I think I would go with 8". You are likely to get insufficient draft if you go with less than spec'd. If insufficient draft is the result, neither you nor the stove will be happy.

That would normally be true, Jim, but as I recall from a past discussion, all Econoburn boilers have 8" chimney outlets, but the smaller units can do fine with 6" according to the factory and heaterman, who is a dealer. According to heaterman, all the company has to do is state in the manual that certain models can be fitted to a 6" chimney in order for it to be legal/code complaint to go with the smaller diameter.

Sooooo.... can anyone tell me for sure that the Econoburn installation instructions state that 6" pipe may be used ? I know that what really counts is maintaining sufficient draft but that is much harder to force by code.

 

[Eric Johnson]

I'd call the company and ask, because that's the only opinion that counts.

 

[Loki]

I just spoke with Hank at Econoburn. Sliming down the pipe from 8" to 6" should not be a problem as long as the correct draft can be maintained. He indicated that correct draft was 0.2 but was not sure of what units that is in.

mm of Hg ??

inches of H2O ??

furlongs of ferret fur ??

Hopefully the installation instructions reveal that which is hidden.

 

[webbie]

.02 inches of water. On a low BTU boiler (under 120K) a decently tall chimney of 6" should be fine. If it goes into the wide side of a reactangle (8x12 OD), you could always replace the crock with a 7" or even 8" if you want to.

In most cases you don't have to actually measure the draft - it will differ widely depending on weather, wood, etc.

 

[antknee2]

If your chimney is properly built for solid fuel , and inspected by a pro , located on inside walls of your house an capable of maintaining a negative draft of .02''min and .05'' max w.c. , at all times and conditions it should work fine in my opinion . Also Econoburn recommends that a draft regulator be used to prevent excess draft which could lead to boiler over firing . Anthony

Could you elaborate more on the draft requirements quoted? Is there some instrumentation to gauge the draft ect?
Thanks. MM

From the research that I have done on the subject of Econoburn boilers is they will only sell it to you if you are going to have it installed and serviced annually by a licenced and insured professional who understands wood fired boilers and all the all the dangers of having a high efficiency boiler with a very picky apatite . I would say let your installer worry about all the details and as a future boiler owner get going on stacking an splitting your wood , fastest way is let the sun bake it all summer and only cover it if rain is in the forecast . Anthony

 

[jebatty]

When Econoburn is talking "draft regulator," isn't that just a barometric damper, with all of its shortcomings and risks? Or is it something else.

 

[Eric Johnson]

Econoburn maintains a tech help line, which is 716-792-2095. The toll-free number gets you to the sales department.

 

[mtnmizer]

When Econoburn is talking "draft regulator," isn't that just a barometric damper, with all of its shortcomings and risks? Or is it something else.

That's it. If I understand the situation, wood boilers will overdraft if not equiped with
a "draft regulator" aka barometric damper. The overdraft will cause the boiler to "over fire" ?
Is that because they are forced draft intake?

Anyone using/have knowledge of these devices? The factory assured me that they are essential to
proper function of their units.

All the wood stoves I've owned didn't have anything like that installed. MM

 

[jebatty]

If I understand the situation, wood boilers will overdraft if not equipped with
a “draft regulator” aka barometric damper. The overdraft will cause the boiler to “over fire” ? Is that because they are forced draft intake?

Not so. Can't speak for others, but Tarm does not recommend one. My old OWB did not have one, and it also was forced draft. My wood stove does not have one. While many variables affect draft and over or under firing, the bottom line to me seems to be how the boiler is engineered. If engineered properly, the boiler should be able to operate reasonably in diverse conditions without a barometric damper.

The barometric damper is an attempt to have an inexpensive, although a little risky and an energy waster, solution to a complex problem.

 

[mtnmizer]

If I understand the situation, wood boilers will overdraft if not equipped with
a “draft regulator” aka barometric damper. The overdraft will cause the boiler to “over fire” ? Is that because they are forced draft intake?

If engineered properly, the boiler should be able to operate reasonably in diverse conditions without a barometric damper.

The barometric damper is an attempt to have an inexpensive, although a little risky and an energy waster, solution to a complex problem.

My understanding of the barometric damper is that it allows the appliance to operate independently of the
flue, and are used for oil, coal and wood systems. A quick google gives numerous hits, seems to be a
commonly used device. A local hvac shop explained to me that it would be closed most of the time,
but would allow extra flow in high winds ect. MM

 

[pybyr]

What's interesting here (with this topic of barometric dampers) is that even though Tarm USA apparently does not recommend a barometric damper, when you go to the YouTube videos that Hansson (who's a member here on the boiler room forum) posted of his set up in Sweden, it, to my surprise, shows a barometric damper with his Tarm- and he's got the most advanced Tarm. Standard (pre-wood-gasifier) view in USA seems to be against a barometric damper type draft control on any solid fuel appliance, so perhaps Tarm is influenced by that prevailing norm?

My current biggest hesitation about a barometric damper on my forthcoming wood gasifier is that it creates a situation where, even during times the boiler isn't running, it's going to be sending inside-house air up the chimney, which'll create a draw for drafts elsewhere in the house. That, plus the points others have noted, has me wondering whether I might be better off putting a manual damper in the smoke pipe, and adjusting that damper for desired draft based on the actual draw as measured on the Bacharach draft guage (big model) that I already own.