Tall chimney + insert = trouble?

[AstroBoy]

I'm planning on installing an insert in our masonry fireplace (exterior wall, 2.5 story house, ~30-foot chimney), and have been trying to read as much as I can here to understand potential issues before I take the plunge. (This will be my first stove/insert.) I really appreciate all of the collective wisdom and helpfulness of people here.

In my reading here, I've seen a number of threads that go something like this:

- I'm having problems with my insert burning too hot / too fast / overfiring.
-- How tall is your chimney?
- 30 feet.
-- Probably too much draft.

What I can't tell, of course, is how common those problems really are. People who don't have problems probably (mostly) aren't posting, or if they do, the might not say how tall their chimney is, etc.

So... how much should I worry about this as I'm looking at inserts and talking to dealers/installers? I know that every setup can be a little different, but curious to hear the collective wisdom here. Should I be looking at getting some kind of damper installed right from the start? (Not so simple in an insert, it seems.)

And on a related note, if anyone can point me to a good discussion of the physics of how draft works in chimneys, that would be great! I do in fact have a physics background. But that doesn't mean I know anything about this particular topic 😆 , just that I don't mind a pretty technical explanation. (A web search for "chimney physics" brings up a bunch of links, but I bet the experts here have some favorites.)

 

[begreen]

Woodheat.org has good chimney info.

A non-commercial service in support of responsible home heating with wood - All About Chimneys

The Wood Heat Organization was formed to support the public in the responsible use of wood energy in the home. We fulfill our mandate by providing reliable information, by conducting research into wood heating-related issues and by representing the public interest in discussions of policies that...

woodheat.org

 

[EbS-P]

I'm planning on installing an insert in our masonry fireplace (exterior wall, 2.5 story house, ~30-foot chimney), and have been trying to read as much as I can here to understand potential issues before I take the plunge. (This will be my first stove/insert.) I really appreciate all of the collective wisdom and helpfulness of people here.

In my reading here, I've seen a number of threads that go something like this:

- I'm having problems with my insert burning too hot / too fast / overfiring.
-- How tall is your chimney?
- 30 feet.
-- Probably too much draft.

What I can't tell, of course, is how common those problems really are. People who don't have problems probably (mostly) aren't posting, or if they do, the might not say how tall their chimney is, etc.

So... how much should I worry about this as I'm looking at inserts and talking to dealers/installers? I know that every setup can be a little different, but curious to hear the collective wisdom here. Should I be looking at getting some kind of damper installed right from the start? (Not so simple in an insert, it seems.)

And on a related note, if anyone can point me to a good discussion of the physics of how draft works in chimneys, that would be great! I do in fact have a physics background. But that doesn't mean I know anything about this particular topic 😆 , just that I don't mind a pretty technical explanation. (A web search for "chimney physics" brings up a bunch of links, but I bet the experts here

I installed an insert in 24’ of insulated liner with one 8” horizontal offset and needed a damper.

 

[bholler]

I'm planning on installing an insert in our masonry fireplace (exterior wall, 2.5 story house, ~30-foot chimney), and have been trying to read as much as I can here to understand potential issues before I take the plunge. (This will be my first stove/insert.) I really appreciate all of the collective wisdom and helpfulness of people here.

In my reading here, I've seen a number of threads that go something like this:

- I'm having problems with my insert burning too hot / too fast / overfiring.
-- How tall is your chimney?
- 30 feet.
-- Probably too much draft.

What I can't tell, of course, is how common those problems really are. People who don't have problems probably (mostly) aren't posting, or if they do, the might not say how tall their chimney is, etc.

So... how much should I worry about this as I'm looking at inserts and talking to dealers/installers? I know that every setup can be a little different, but curious to hear the collective wisdom here. Should I be looking at getting some kind of damper installed right from the start? (Not so simple in an insert, it seems.)

And on a related note, if anyone can point me to a good discussion of the physics of how draft works in chimneys, that would be great! I do in fact have a physics background. But that doesn't mean I know anything about this particular topic 😆 , just that I don't mind a pretty technical explanation. (A web search for "chimney physics" brings up a bunch of links, but I bet the experts here have some favorites.)

With 30' of chimney you will have excessive draft no question. Some stoves will deal with that better than others but I would absolutely recommend a damper to control it.

 

[mellow]

Insert install.

An offset box adapter is ok for insert installs and can hamper draft which is a good thing in overdraft installs:

Off-Set Box & Insert Adapter for Flexible Chimney Liner Systems - Rockford Chimney

Shop Adapters: A two-piece adapter for fireplace inserts. Off-set box allows you to adjust the insert front and back from inside firebox. Free shipping.

www.rockfordchimneysupply.com

 

[stoveliker]

I understand the draft argument of that offset, but I'd be concerned about blockage there. If you use this, keep an eye on keeping things flowing in there both during burning and when cleaning the chimney.

 

[davidmsem]

With 30' of chimney you will have excessive draft no question. Some stoves will deal with that better than others but I would absolutely recommend a damper to control it.

So what controls the damper? Is there a gauge that measures pressure or temperature or something? When you set a fire at night and have to go to bed do you have to wait up and sit there and control the damper? What criteria and metrics are used to adjust the damper?

 

[bholler]

So what controls the damper? Is there a gauge that measures pressure or temperature or something? When you set a fire at night and have to go to bed do you have to wait up and sit there and control the damper? What criteria and metrics are used to adjust the damper?

A handle run through the surround controls it.

Yes there are gauges that measure draft which could be used but generally if there is an issue I just use mine and make sure it can be brought into spec.

I would absolutely recommend a remote digital temp probe.

No you don't have to stay up adjusting it. You will quickly figure out what settings work for your setup. It should be cruising along nicely within 15 mins or less typically.

 

[davidmsem]

A handle run through the surround controls it.

Yes there are gauges that measure draft which could be used but generally if there is an issue I just use mine and make sure it can be brought into spec.

I would absolutely recommend a remote digital temp probe.

No you don't have to stay up adjusting it. You will quickly figure out what settings work for your setup. It should be cruising along nicely within 15 mins or less typically.

So to the person's original question, you probably saw a post recently and somebody responded to my 28-ft run. My unit always ran "within spec", and I measured temperatures with the laser very often especially when I was learning the unit. So this thing was not running away. I think the real issue is you're going to make a big investment, thousands and thousands of dollars, commit to many hours and dollars to get firewood and tools, wrestle with getting warm air around your house with fans and the like you will spend money on. Is it worth it, I'm not so sure anymore after my unit only lasting seven seasons. I'm an OCD engineer who works on jet engines and the guy in the neighborhood always does things correctly. Units fail, parts fail, just like on jet engines and other assemblies. There are weak spots etc. The pictures of my unit match the pictures of other units online and have cracks in the same area. This is no free ride. It's expensive, it's a big commitment to work, and you are taking a chance on a company and their advertised warranty. I'm fighting all of this now. Proceed with caution.

 

[bholler]

So to the person's original question, you probably saw a post recently and somebody responded to my 28-ft run. My unit always ran "within spec", and I measured temperatures with the laser very often especially when I was learning the unit. So this thing was not running away. I think the real issue is you're going to make a big investment, thousands and thousands of dollars, commit to many hours and dollars to get firewood and tools, wrestle with getting warm air around your house with fans and the like you will spend money on. Is it worth it, I'm not so sure anymore after my unit only lasting seven seasons. I'm an OCD engineer who works on jet engines and the guy in the neighborhood always does things correctly. Units fail, parts fail, just like on jet engines and other assemblies. There are weak spots etc. The pictures of my unit match the pictures of other units online and have cracks in the same area. This is no free ride. It's expensive, it's a big commitment to work, and you are taking a chance on a company and their advertised warranty. I'm fighting all of this now. Proceed with caution.

Ok did you register the stove with regency when you got it? Did you fill out the data page in the back of the manual with the serial number? I am sorry to be a bit harsh about it but what is required for a warranty claim is spelled out in the manual. Yes your dealer should have reminded you of all of that we even fill out the data and keep everything on record. But ultimately you should have done it if they hadn't. As a dealer I can tell you that with the proper info regency is very good about honoring their warranty.

Yes there certainly are other regencies that have cracked. Not an abnormal number compared to other similar stoves but it does happen.

What temperatures were you typically seeing and where?

 

[davidmsem]

Ok did you register the stove with regency when you got it? Did you fill out the data page in the back of the manual with the serial number? I am sorry to be a bit harsh about it but what is required for a warranty claim is spelled out in the manual. Yes your dealer should have reminded you of all of that we even fill out the data and keep everything on record. But ultimately you should have done it if they hadn't. As a dealer I can tell you that with the proper info regency is very good about honoring their warranty.

Yes there certainly are other regencies that have cracked. Not an abnormal number compared to other similar stoves but it does happen.

What temperatures were you typically seeing and where?

Dealer took a deposit, and was going into financial bankruptcy. Many months later I was still fighting with him to get my unit. Visiting his shop frequently pressuring him to deliver it. Just before he shut the doors, eventually selling the place to another pair of people, my unit was installed. I'm lucky I have the unit let alone paperwork and everything else. Because of this I took pictures of the truck in the driveway the crew doing the install and I have pictures of it for years. So unless somebody's an attorney about the paperwork they would be reasonable about what one of their dealers did to their customer. The new owners have no records of anything. So my situation is my situation, but anybody out there dealing with these units and deciding on the huge commitment of time money backbreaking work should be completely aware of the difficult situations and financial loss some people experience.

I'm monitor the temperature by checking the face plate I had no fancy internal probes but who the hell is doing that? What percentage are doing that. I had a laser shot on the face, and eventually found some metal attaching thermometer indicators that would be very close to the laser indicated temperatures. Those two devices work very well for the 7 years. You can be harsh all you want but I'm a good consumer who put out a lot of money and is looking at getting screwed right now. Be harsh all you want you're not the one losing money and an investment in time and backbreaking work.

 

[bholler]

Dealer took a deposit, and was going into financial bankruptcy. Many months later I was still fighting with him to get my unit. Visiting his shop frequently pressuring him to deliver it. Just before he shut the doors, eventually selling the place to another pair of people, my unit was installed. I'm lucky I have the unit let alone paperwork and everything else. Because of this I took pictures of the truck in the driveway the crew doing the install and I have pictures of it for years. So unless somebody's an attorney about the paperwork they would be reasonable about what one of their dealers did to their customer. The new owners have no records of anything. So my situation is my situation, but anybody out there dealing with these units and deciding on the huge commitment of time money backbreaking work should be completely aware of the difficult situations and financial loss some people experience.

I'm monitor the temperature by checking the face plate I had no fancy internal probes but who the hell is doing that? What percentage are doing that. I had a laser shot on the face, and eventually found some metal attaching thermometer indicators that would be very close to the laser indicated temperatures. Those two devices work very well for the 7 years. You can be harsh all you want but I'm a good consumer who put out a lot of money and is looking at getting screwed right now. Be harsh all you want you're not the one losing money and an investment in time and backbreaking work.

I really am sorry you are having this experience. But I don't really think it is fair to bash a company for not honoring their warranty. When to start you don't even know that they are not going to. And you don't have the information required to file the claim.

Can you tell us what temps you were seeing?

As far as who runs a probe? Many people. I offer one to every customer I sell an insert to as an option and many of them take me up on that offer. Many here are doing it as well.

 

[EbS-P]

Insert install.

An offset box adapter is ok for insert installs and can hamper draft which is a good thing in overdraft installs:

Off-Set Box & Insert Adapter for Flexible Chimney Liner Systems - Rockford Chimney

Shop Adapters: A two-piece adapter for fireplace inserts. Off-set box allows you to adjust the insert front and back from inside firebox. Free shipping.

www.rockfordchimneysupply.com

I’d rather have a damper at the adapter. Cleaning with the offset box seems more complicated

 

[bholler]

I’d rather have a damper at the adapter. Cleaning with the offset box seems more complicated

It is those things are a pita.

 

[davidmsem]

I really am sorry you are having this experience. But I don't really think it is fair to bash a company for not honoring their warranty. When to start you don't even know that they are not going to. And you don't have the information required to file the claim.

Can you tell us what temps you were seeing?

As far as who runs a probe? Many people. I offer one to every customer I sell an insert to as an option and many of them take me up on that offer. Many here are doing it as well.

Whatever.

 

[JonH]

A handle run through the surround controls it.

Yes there are gauges that measure draft which could be used but generally if there is an issue I just use mine and make sure it can be brought into spec.

I would absolutely recommend a remote digital temp probe.

No you don't have to stay up adjusting it. You will quickly figure out what settings work for your setup. It should be cruising along nicely within 15 mins or less typically.

Not trying to hijack this thread but I am in the OPs shoes and wanted to share my situation. My chimney is right at 30'-35' (one sweep said 35 and another said 30 so I'll be climbing up and measuring it myself on my next day off), I have accidently become obsessed and addicted with wood burning inserts and really want the Lopi large flush nextgen as my first wood burning insert but the manual said the maximum recommended liner length is 33'. I brought this up to my potential dealer/installer and he shares my concern I will have overdraft and said he was going to contact the company and ask if dropping down from from a 6" to a 5.5" liner will be enough to slow the draft. I mentioned a damper and the installer said he doesn't really like dampers especially with inserts but he was going to reach out to Lopi about 5.5" liner and also do some math of his own and get back to me with some options. I'd love to hear some opinions and get some ideas on solutions. If it comes up to 30' and is under Lopi's 33' limit should I just roll with it, or is that still tall enough to cause problems? I apologize if this is considered "hijacking", I'm new here and new to the world of posting on forums.

 

[MAD MARK]

Whatever.

Being an engineer, I consider this response as a non-response. Always find the answer correctly no matter positive or negative the situation and whoever is in it. Its due diligence to make sure the "problem" is rectified.

 

[davidmsem]

Being an engineer, I consider this response as a non-response. Always find the answer correctly no matter positive or negative the situation and whoever is in it. Its due diligence to make sure the "problem" is rectified.

Whatever.

 

[Ctwoodtick]

I smell a troll.

 

[bholler]

Not trying to hijack this thread but I am in the OPs shoes and wanted to share my situation. My chimney is right at 30'-35' (one sweep said 35 and another said 30 so I'll be climbing up and measuring it myself on my next day off), I have accidently become obsessed and addicted with wood burning inserts and really want the Lopi large flush nextgen as my first wood burning insert but the manual said the maximum recommended liner length is 33'. I brought this up to my potential dealer/installer and he shares my concern I will have overdraft and said he was going to contact the company and ask if dropping down from from a 6" to a 5.5" liner will be enough to slow the draft. I mentioned a damper and the installer said he doesn't really like dampers especially with inserts but he was going to reach out to Lopi about 5.5" liner and also do some math of his own and get back to me with some options. I'd love to hear some opinions and get some ideas on solutions. If it comes up to 30' and is under Lopi's 33' limit should I just roll with it, or is that still tall enough to cause problems? I apologize if this is considered "hijacking", I'm new here and new to the world of posting on forums.

I do not sell lopis and have never installed one. So I don't know the answer for sure. But talking to lopi is a good idea for sure. Going to 5.5 may help but probably won't change much.

 

[davidmsem]

I'm planning on installing an insert in our masonry fireplace (exterior wall, 2.5 story house, ~30-foot chimney), and have been trying to read as much as I can here to understand potential issues before I take the plunge. (This will be my first stove/insert.) I really appreciate all of the collective wisdom and helpfulness of people here.

In my reading here, I've seen a number of threads that go something like this:

- I'm having problems with my insert burning too hot / too fast / overfiring.
-- How tall is your chimney?
- 30 feet.
-- Probably too much draft.

What I can't tell, of course, is how common those problems really are. People who don't have problems probably (mostly) aren't posting, or if they do, the might not say how tall their chimney is, etc.

So... how much should I worry about this as I'm looking at inserts and talking to dealers/installers? I know that every setup can be a little different, but curious to hear the collective wisdom here. Should I be looking at getting some kind of damper installed right from the start? (Not so simple in an insert, it seems.)

And on a related note, if anyone can point me to a good discussion of the physics of how draft works in chimneys, that would be great! I do in fact have a physics background. But that doesn't mean I know anything about this particular topic 😆 , just that I don't mind a pretty technical explanation. (A web search for "chimney physics" brings up a bunch of links, but I bet the experts here have some favorites.)

I don't think you're going to get a clear answer on the installation of a damper or offset plate etc. As I'm shopping for a new unit to replace mine other dealers in the area are saying there should be no problem with the setup I have. Realize if you add a damper you've got another variable in running your stove or insert. What criteria are you going to use the move the damper? Unless there's some quantitative measure it's kind of guesswork. So if your unit is like mine you will have an air flow lever to vary the fan high to low and now a damper. I was driving mine based on temperature, and when it got up towards the high range of normal operation I would run my fan high often to pull heat out of the unit into the room and house. People make it sound like 30 ft of flue make it over fire but that just wasn't the case with an easy breathing unit that I had. Don't drive yourself too nuts with the setup you create. If dampers and offset boxes and things discussed here were so essential, there would be more literature in owners manuals and installation manuals about these things. There was none of that in the unit I purchased. Install per the directions of the manufacturer. If it's a good company and there's an issue you will get warranty coverage.

 

[bholler]

I don't think you're going to get a clear answer on the installation of a damper or offset plate etc. As I'm shopping for a new unit to replace mine other dealers in the area are saying there should be no problem with the setup I have. Realize if you add a damper you've got another variable in running your stove or insert. What criteria are you going to use the move the damper? Unless there's some quantitative measure it's kind of guesswork. So if your unit is like mine you will have an air flow lever to vary the fan high to low and now a damper. I was driving mine based on temperature, and when it got up towards the high range of normal operation I would run my fan high often to pull heat out of the unit into the room and house. People make it sound like 30 ft of flue make it over fire but that just wasn't the case with an easy breathing unit that I had. Don't drive yourself too nuts with the setup you create. If dampers and offset boxes and things discussed here were so essential, there would be more literature in owners manuals and installation manuals about these things. There was none of that in the unit I purchased. Install per the directions of the manufacturer. If it's a good company and there's an issue you will get warranty coverage.

Ok I am sorry but I deal with installs like this every day. I take actual draft measurements and flue temp measurements regularly. The fan is not meant to control heat it's just meant to get extra heat into the room. With the little info you have given us I see indicators that your unit was over drafting.

In general manufacturers won't give info on modifications because they are not allowed to but units need to be run within the draft specifications.

Can you tell us what temps you were seeing and where?

 

[brenndatomu]

So if your unit is like mine you will have an air flow lever to vary the fan high to low and now a damper. I was driving mine based on temperature, and when it got up towards the high range of normal operation I would run my fan high often to pull heat out of the unit into the room and house. People make it sound like 30 ft of flue make it over fire but that just wasn't the case with an easy breathing unit that I had.

Unless you were monitoring the draft with a manometer or magnehelic gauge, you have no idea if you overfired or not...its like driving a car by using the tach only, no speedo...no way to know for sure how fast you were going. If you look around here a little bit, there are threads going on right now where people are finding that their temp readings make no sense with the way their stove is working...or flue temp and stove top temp are drastically different...gotta have a mano or mag gauge on the flue to know what's what, especially on an insert stove.
IME chances are very good that with a chimney over 25' tall and cold weather, draft is above spec/too high...the taller the chimney, and the colder the weather, the more often and the higher the draft tends to go. Some stoves allow for better control than others, but on most stoves with secondary air tubes, there is no control of the secondary air, primary only...so having proper draft spec is important.
I have said it here before, but I'll say it again, I am completly shocked that this issue isn't addressed much, or at all in many/most stove owners manuals!

 

[davidmsem]

Unless you were monitoring the draft with a manometer or magnehelic gauge, you have no idea if you overfired or not...its like driving a car by using the tach only, no speedo...no way to know for sure how fast you were going. If you look around here a little bit, there are threads going on right now where people are finding that their temp readings make no sense with the way their stove is working...or flue temp and stove top temp are drastically different...gotta have a mano or mag gauge on the flue to know what's what, especially on an insert stove.
IME chances are very good that with a chimney over 25' tall and cold weather, draft is above spec/too high...the taller the chimney, and the colder the weather, the more often and the higher the draft tends to go. Some stoves allow for better control than others, but on most stoves with secondary air tubes, there is no control of the secondary air, primary only...so having proper draft spec is important.
I have said it here before, but I'll say it again, I am completly shocked that this issue isn't addressed much, or at all in many/most stove owners manuals!

So if what you are putting forth is true means that the regency owner and installation manual did not cover issues it should have? And it should have been operated in a manner different than specified in the owners and installation manual? If true I wonder if this is an error of omission or commission by Regency. That is very troubling.

 

[JonH]

I do not sell lopis and have never installed one. So I don't know the answer for sure. But talking to lopi is a good idea for sure. Going to 5.5 may help but probably won't change much.

Thank you, do you have certain inserts you recommend for tall chimneys? Or do you prefer to install dampers when above 30’?