Furnace Chimney Relining

[chiefs15]

Hi all,

I've been a long-time reader and am thankful for the information available on the forum. I'm in the middle of making some difficult decisions about whether to continue to burn with our wood furnace or not and am seeking advice from those that know more than I on this. I'll try to keep this concise as possible but I tend to ramble.

First, some background info: Wife and I bought a house with a wood furnace system installed a couple years ago. The house and furnace are about 27 years old. We primarily heat with our propane furnace. Ran the wood furnace maybe half of the time last winter but have not burned this year as I know there are cracks and offsets in the clay tile liner from the house moving and I don't feel safe burning until the liner problem is fixed. I don't have much experience heating with wood and want to make sure its safe, especially with our little ones. I even paid a chimney sweep to come out and inspect and he looked down the chimney very briefly and told me it was fine, but I really don't think it is. I've been looking into stainless liners, specifically heavy wall flex liners to be able to navigate the shifts in the clay tiles. This is a two story chimney almost in the middle of the house. I measured and believe the clay liner is 7 by 11 inside diameter. I've attached photos of the furnace and chimney set up for reference.

I've thought through several problems/questions along the way:

1. I am unsure on the flue diameter needed for this furnace. Unfortunately, I don't have any info on the furnace other than knowing it has an 8 inch pipe from the furnace to the chimney. I am assuming this means I need an 8 inch flue up the chimney as well? Or would I be able to use a liner small enough that I could install in the existing 7x11 clay liner? I got to wondering whether the only way to make this setup work would be to remove the clay liner first, which, without knowing much about that process, seems like it would be an absolute nightmare.

2. The wood furnace supply duct is tied in with our propane ducts. We had our propane furnace worked on over the weekend and the repair man suggested having each on their own separate duct system so that its easier on the blowers for each. I don't think this would be too terribly difficult to accomplish, but for those with similar setups, would you advise putting them on two separate ducts or should it be fine as is? One issue, for example, is that I think the damper between the propane supply and wood furnace supply duct is hanging up and causing the propane furnace to get too hot.

3. This isn't a question, but I'd be interested to hear if anyone knows anything at all about this furnace. I've searched and searched online but have never found any information on it at all. Manufactured in 1991 by King Products Division of Martin Industries in Florence, AL. Looks like Martin Industries filed for bankruptcy and was bought in 2003 by Monessen Hearth Systems. Just curious as to whether anyone knows if this should be a decent set up or not. Lack of info available makes it seem like maybe its not a common furnace.

I love the idea of burning with wood. I like cutting firewood, the ability to use as an emergency heat source, and cost savings. But I'm really struggling to determine what to do from here before I invest the time/money into making the setup safe. I'd really appreciate any guidance that can be offered and am happy to provide as much information as needed for clarity.

Thank you!
Travis

 

[bholler]

Hi all,

I've been a long-time reader and am thankful for the information available on the forum. I'm in the middle of making some difficult decisions about whether to continue to burn with our wood furnace or not and am seeking advice from those that know more than I on this. I'll try to keep this concise as possible but I tend to ramble.

First, some background info: Wife and I bought a house with a wood furnace system installed a couple years ago. The house and furnace are about 27 years old. We primarily heat with our propane furnace. Ran the wood furnace maybe half of the time last winter but have not burned this year as I know there are cracks and offsets in the clay tile liner from the house moving and I don't feel safe burning until the liner problem is fixed. I don't have much experience heating with wood and want to make sure its safe, especially with our little ones. I even paid a chimney sweep to come out and inspect and he looked down the chimney very briefly and told me it was fine, but I really don't think it is. I've been looking into stainless liners, specifically heavy wall flex liners to be able to navigate the shifts in the clay tiles. This is a two story chimney almost in the middle of the house. I measured and believe the clay liner is 7 by 11 inside diameter. I've attached photos of the furnace and chimney set up for reference.

I've thought through several problems/questions along the way:

1. I am unsure on the flue diameter needed for this furnace. Unfortunately, I don't have any info on the furnace other than knowing it has an 8 inch pipe from the furnace to the chimney. I am assuming this means I need an 8 inch flue up the chimney as well? Or would I be able to use a liner small enough that I could install in the existing 7x11 clay liner? I got to wondering whether the only way to make this setup work would be to remove the clay liner first, which, without knowing much about that process, seems like it would be an absolute nightmare.

2. The wood furnace supply duct is tied in with our propane ducts. We had our propane furnace worked on over the weekend and the repair man suggested having each on their own separate duct system so that its easier on the blowers for each. I don't think this would be too terribly difficult to accomplish, but for those with similar setups, would you advise putting them on two separate ducts or should it be fine as is? One issue, for example, is that I think the damper between the propane supply and wood furnace supply duct is hanging up and causing the propane furnace to get too hot.

3. This isn't a question, but I'd be interested to hear if anyone knows anything at all about this furnace. I've searched and searched online but have never found any information on it at all. Manufactured in 1991 by King Products Division of Martin Industries in Florence, AL. Looks like Martin Industries filed for bankruptcy and was bought in 2003 by Monessen Hearth Systems. Just curious as to whether anyone knows if this should be a decent set up or not. Lack of info available makes it seem like maybe its not a common furnace.

I love the idea of burning with wood. I like cutting firewood, the ability to use as an emergency heat source, and cost savings. But I'm really struggling to determine what to do from here before I invest the time/money into making the setup safe. I'd really appreciate any guidance that can be offered and am happy to provide as much information as needed for clarity.

Thank you!
Travis
View attachment 257178View attachment 257179View attachment 257180View attachment 257181

As far as lining the chimney yes you will need an 8" liner and it will need to be insulated. That means you will need to break out the clay tiles and go with an oval or rectangle liner of equal volume as an 8" round liner so you have room for the liner and insulation. You also have some pretty serious clearance problems from both the furnace and pipe to that drywall

 

[chiefs15]

As far as lining the chimney yes you will need an 8" liner and it will need to be insulated. That means you will need to break out the clay tiles and go with an oval or rectangle liner of equal volume as an 8" round liner so you have room for the liner and insulation. You also have some pretty serious clearance problems from both the furnace and pipe to that drywall

I appreciate the info! That is what I was afraid of. I wouldn't be too terrified of the work involved but I have concerns about the integrity of the chimney after beating up on the clay tiles. As for the clearances, according to the furnace specs I need at least 6 inches from that wall for the box. Am I right in that the pipe into the chimney should be at least 18 inches from that wall? If so, I don't see any way of making this set up work safely. I suppose better to figure out now than before I start throwing a bunch of money into it.

 

[chiefs15]

I appreciate the info! That is what I was afraid of. I wouldn't be too terrified of the work involved but I have concerns about the integrity of the chimney after beating up on the clay tiles. As for the clearances, according to the furnace specs I need at least 6 inches from that wall for the box. Am I right in that the pipe into the chimney should be at least 18 inches from that wall? If so, I don't see any way of making this set up work safely. I suppose better to figure out now than before I start throwing a bunch of money into it.

I should add that the drywall is fire-rated if that makes any difference. To be honest, I'm not certain on whether that is considered a combustible material or not or if that would make much difference. I'd be interested in knowing more about the clearance issues you mentioned bholler. Essentially, I am trying to figure out if this is worth the investment or not. And at this point, if its even doable from a safety standpoint.

 

[bholler]

I appreciate the info! That is what I was afraid of. I wouldn't be too terrified of the work involved but I have concerns about the integrity of the chimney after beating up on the clay tiles. As for the clearances, according to the furnace specs I need at least 6 inches from that wall for the box. Am I right in that the pipe into the chimney should be at least 18 inches from that wall? If so, I don't see any way of making this set up work safely. I suppose better to figure out now than before I start throwing a bunch of money into it.

Yes 6" for the furnace and 18" for the pipe. The pipe can be shielded or changed out to doublewall to reduce clearances but the furnace can't be reduced

 

[bholler]

I should add that the drywall is fire-rated if that makes any difference. To be honest, I'm not certain on whether that is considered a combustible material or not or if that would make much difference. I'd be interested in knowing more about the clearance issues you mentioned bholler. Essentially, I am trying to figure out if this is worth the investment or not. And at this point, if its even doable from a safety standpoint.

Fire rated is not noncombustible. It is just rated to resist burn through for a given time period. And I assume it is over wood studs as well right?

 

[chiefs15]

Fire rated is not noncombustible. It is just rated to resist burn through for a given time period. And I assume it is over wood studs as well right?

Yep it is over wood studs. This leads to next questions of how much you think this furnace would be worth? It seemed to work just fine including the electrical. A few hundred maybe?

I also wonder how big of a pain it would be to get out of there. Thanks again for the guidance!

 

[bholler]

Yep it is over wood studs. This leads to next questions of how much you think this furnace would be worth? It seemed to work just fine including the electrical. A few hundred maybe?

I also wonder how big of a pain it would be to get out of there. Thanks again for the guidance!

Yeah 3 maybe 4 hundred