Replacing manufactured fireplace with wood burning stove

[Paul the Project guy]

I just joined this group so be nice to me .
My home has an old manufactured fireplace with an air cooled chimney. I am planning to tear out the fireplace and replace it with a free standing wood burning stove. I intend to use class A double lined vent.
Now for my question: Can I run the class A vent through the current air cooled fireplace vent? I don't know why this would be bad but I am curious what the experts think (that would be you folks). Thanks

 

[begreen]

Might be possible if the ID of the air cooled is larger than the OD of the new chimney, but there are other factors to consider. Like, what supports the new chimney pipe and how? And is the location right for clearances? What is to be gained?

This type of ZC replacement is possible, but it takes planning, especially if the stove is to be sitting in an alcove. Clearances are usually the controlling factor over stove choice here.

 

[moresnow]

Welcome to Hearth.
If your tearing it all out I'd start fresh. No complications/hurdles with all new components that are designed to work together. What stove are you installing out of curiosity?
Hello from IA by the way. My sister lives in CR.

 

[Paul the Project guy]

I am installing a Pleasant Hearth LWS 2200 from Menards. I kind of want to leave the current air cooled fireplace vent intact so I won't have to deal with thimbles and resizing the opening in my roof and all that is involved with that. The idea of slipping the Class A pipe into the current vent is very appealing and a lot less hassle. The OD of the Class A pipe I will be using is 8" (6" ID). The OD of my current fireplace air cooled vent is 12" (not sure of ID until I rip into it).
The new chimney will actually attach right into the stove... a straight shot up.
As far as clearance goes, the back of the current fireplace is in my mud room and the front is in my living room. So, I will build a properly cleared "box" soffit the back of the stove with a register to vent into the mud room. Clearance for the stove, in other words, is not an issue. Clearance for the pipe is already 2" on up through the house. That clearance, plus the Class A pipe inside of it, should (in my thinking) be fine.
But, this is new to me, so I am thankful for your insights.
Howdy to your Iowa sister, Minister of Fire (may I call you reverend? )

 

[bholler]

I am installing a Pleasant Hearth LWS 2200 from Menards. I kind of want to leave the current air cooled fireplace vent intact so I won't have to deal with thimbles and resizing the opening in my roof and all that is involved with that. The idea of slipping the Class A pipe into the current vent is very appealing and a lot less hassle. The OD of the Class A pipe I will be using is 8" (6" ID). The OD of my current fireplace air cooled vent is 12" (not sure of ID until I rip into it).
The new chimney will actually attach right into the stove... a straight shot up.
As far as clearance goes, the back of the current fireplace is in my mud room and the front is in my living room. So, I will build a properly cleared "box" soffit the back of the stove with a register to vent into the mud room. Clearance for the stove, in other words, is not an issue. Clearance for the pipe is already 2" on up through the house. That clearance, plus the Class A pipe inside of it, should (in my thinking) be fine.
But, this is new to me, so I am thankful for your insights.
Howdy to your Iowa sister, Minister of Fire (may I call you reverend? )

You need to pay close attention to the alcove clearance requirements. They are usually much more restrictive than normal requirements.

Typically you don't run chimney pipe from the stove top. You run stove pipe to the ceiling then transition to chimney pipe. Your idea of leaving the existing chimney in place will be problematic because there really won't have anything holding it in place once the fireplace is removed.

 

[Paul the Project guy]

You need to pay close attention to the alcove clearance requirements. They are usually much more restrictive than normal requirements.

Typically you don't run chimney pipe from the stove top. You run stove pipe to the ceiling then transition to chimney pipe. Your idea of leaving the existing chimney in place will be problematic because there really won't have anything holding it in place once the fireplace is removed.

Thank you. I do plan to rest the existing chimney on a wall support and then continue the 6" Class A pipe down to the stove. So, the Class A will go from stove to above the roof while the current pipe would simply act as a heat shield. DOes that make sense?

 

[begreen]

The LWS-2200 is a big stove with even bigger clearance requirements. Is the ZC fireplace installed with a bumpout into the room or as a bumpout of an exterior wall with a chased, exterior chimney?

 

[Paul the Project guy]

The LWS-2200 is a big stove with even bigger clearance requirements. Is the ZC fireplace installed with a bumpout into the room or as a bumpout of an exterior wall with a chased, exterior chimney?

I assume by "bumpout" that you mean the back side of the fireplace. That extends into the room behind the fireplace, which is a concrete floored mudroom. So, I intend to build a soffit around the part of it that is in the mudroom so that you can't see the mudroom from the living room (where the fireplace faces). I will use the heat shielding materials and properly space them. My primary question is: Can I use the current fireplace air cooled pipe to run the Class A double wall through from the ceiling of the mudroom to the top of the chimney?

 

[begreen]

The lowest clearance with proper NFPA 211 wall shielding is 12" and the stove is 27" wide so that means that the width of the area needs to be at least 51" wide. The clearances will also come into play for the rear clearance of the stove. Will 12" put the flue connection directly below the center of the current chimney? And the ceiling height is also important. The stove requires at least 53.375” (1356mm) from stovetop to ceiling.

If the ID of the air cooled chimney is 8", it won't work. If it is 10" and the air-cooled chimney is securely supported then it might.

 

[bholler]

Thank you. I do plan to rest the existing chimney on a wall support and then continue the 6" Class A pipe down to the stove. So, the Class A will go from stove to above the roof while the current pipe would simply act as a heat shield. DOes that make sense?

I understand what you want to do. I just don't see that it makes sense to do it that way. It would be much less complicated and more air and weather tight if you simply removed the old chimney and installed the chimney and connector pipe as intended.

 

[Paul the Project guy]

Mr. BeGreen, The fire stove will sit directly under the chimney. The wall between the mud room and the living room is surrounding the stove. It is 48" across. The wall that will actually be on either side of the stove is only 6 1/2 inches wide. So, it's not like it is enclosed by that 48" space... it is open on both the front and the back but just that one area where it sticks through the wall is it 48. Vertically, we are talking about an opening that is 37" high. Would that be a problem?

Mr. Bholler, so you think it makes more sense to rip out the entire chimney that is there, and have an open Class A vent from the top of the stove, through the ceiling and second floor and attic and then to the opening at the top?

 

[bholler]

Mr. BeGreen, The fire stove will sit directly under the chimney. The wall between the mud room and the living room is surrounding the stove. It is 48" across. The wall that will actually be on either side of the stove is only 6 1/2 inches wide. So, it's not like it is enclosed by that 48" space... it is open on both the front and the back but just that one area where it sticks through the wall is it 48. Vertically, we are talking about an opening that is 37" high. Would that be a problem?

Mr. Bholler, so you think it makes more sense to rip out the entire chimney that is there, and have an open Class A vent from the top of the stove, through the ceiling and second floor and attic and then to the opening at the top?

No I think it makes more sense to remove what's there and install the new chimney with all of the required supports firestops and proper flashing to protect from drafts weather and fire as required by code.

 

[moresnow]

I am installing a Pleasant Hearth LWS 2200 from Menards. I kind of want to leave the current air cooled fireplace vent intact so I won't have to deal with thimbles and resizing the opening in my roof and all that is involved with that. The idea of slipping the Class A pipe into the current vent is very appealing and a lot less hassle. The OD of the Class A pipe I will be using is 8" (6" ID). The OD of my current fireplace air cooled vent is 12" (not sure of ID until I rip into it).
The new chimney will actually attach right into the stove... a straight shot up.
As far as clearance goes, the back of the current fireplace is in my mud room and the front is in my living room. So, I will build a properly cleared "box" soffit the back of the stove with a register to vent into the mud room. Clearance for the stove, in other words, is not an issue. Clearance for the pipe is already 2" on up through the house. That clearance, plus the Class A pipe inside of it, should (in my thinking) be fine.
But, this is new to me, so I am thankful for your insights.
Howdy to your Iowa sister, Minister of Fire (may I call you reverend? )

Your getting solid advice here. Strongly consider it. Post some pics of the project.

You actually can legally call me reverend. It was a brief career. One day!

 

[kennyp2339]

Personally if your hard set on not touching the air cooled chimney then run an insulated flex liner down it, the contraindication is that stoves can not go into a zero clearance unit unless the zero clearance unit specifically says that its rated for it without modification to the existing vents, and I dont see how once you remove the zero clearance stove the old air cooled chimney will be anchored, hence rip out the whole thing, install the class A pipe to spec with the proper anchor supports and install the stove to spec w/ all the clearances followed.

 

[begreen]

Mr. BeGreen, The fire stove will sit directly under the chimney. The wall between the mud room and the living room is surrounding the stove. It is 48" across. The wall that will actually be on either side of the stove is only 6 1/2 inches wide. So, it's not like it is enclosed by that 48" space... it is open on both the front and the back but just that one area where it sticks through the wall is it 48. Vertically, we are talking about an opening that is 37" high. Would that be a problem?

Mr. Bholler, so you think it makes more sense to rip out the entire chimney that is there, and have an open Class A vent from the top of the stove, through the ceiling and second floor and attic and then to the opening at the top?

So it sounds like the stove will sit in front of the 6.5" deep wall recess. Is that correct? If so, then this is not really an alcove install. However, we need to see the location and some sketches of what is planned to catch details that may not be evident. The 37" high opening is definitely a serious and major fire problem. There can be no combustibles above the stove for 53 3/8". The space needs to be opened up. Can you post some pictures of this area?

 

[Paul the Project guy]

Been out of the loop for awhile. Really appreciate your input. I talked to our local fire inspector and he said it is perfectly safe to run a double walled liner through an air cooled chimney. Does anyone have a brand to recommend? The ones sold at Menards, Lowes and Home Depot claim their double walled liners are to be used only in masonry chimneys.

 

[bholler]

Been out of the loop for awhile. Really appreciate your input. I talked to our local fire inspector and he said it is perfectly safe to run a double walled liner through an air cooled chimney. Does anyone have a brand to recommend? The ones sold at Menards, Lowes and Home Depot claim their double walled liners are to be used only in masonry chimneys.

Liners are only for masonry chimneys. No matter what the inspector says you need to follow the manufacturers instructions and the listing criteria.

 

[Paul the Project guy]

Actually, I just found a place that makes liners for air cooled chimneys: https://www.travisindustries.com/Docs/17601809.pdf

 

[stoveliker]

But that is a *manufactured* air-cooled chimney, not some homebuilt chase? What does the NFPA say about that?

 

[bholler]

Actually, I just found a place that makes liners for air cooled chimneys: https://www.travisindustries.com/Docs/17601809.pdf

Did you read the instructions stating that all components of the existing chimney need to be left intact? This system is for installing an insert in the prefab fireplace not what you are intending to do.

Does the manufacturer of your chimney allow for this?

 

[bholler]

But that is a *manufactured* air-cooled chimney, not some homebuilt chase? What does the NFPA say about that?

NFPA says all ul listed products need to be installed per manufacturers instructions. This includes the air cooled chimney.