Fireplace Insert for Heatform Fireplace

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WI-BeechBurner

New Member
Feb 13, 2016
2
Mishicot, WI
First off, I apologize for starting another thread about a topic which has been discussed many times before, but sometimes it's just easier and cleaner to start a new thread (my first one by the way) :).

So, I have a house which was built in 1979 which has a triple flue masonry chimney. The house is a walkout basement style house and looking at the chimney from the lower level, the attic, and the roof it's clear the chimney is made of cinder block with each flue having a rectangular (2 flues) or square (1 flue) clay/tile liner (orange in color). There is a fireplace in the lower level with a heatform firebox, a fireplace on the upper level with a heatform firebox, and I have a central wood burning furnace which located in the lower level that ties into the third flue. The chimney must start out wider at the bottom and narrow as it goes up as the two lower level flues go up, then jog in toward the center and the middle flue (upper level fireplace) goes straight up.

I love my central wood furnace and it's doing a great job, however, when it gets really cold (a few weeks or sometimes months each winter) it is just a tad bit undersized and barely keeps the house at the desired temperature (I have a wife that always seems to be cold so desired temp is above 70 minimum). I'm pondering the thought of trying to put a wood burning fireplace insert into the upper level fireplace.

I really like the look of the upper level fireplace and the builder did a nice job installing real stone and a nice hearth for aesthetics. So, a couple questions I have from reading on this site and pondering. I've read on a thread here that Heatilator and Superior were two common manufacturers who made "heatform" fireplaces back in the day. Many pictures I've seen on this site seem to show three air tubes which connect to discharge vents directly above the fireplace opening. I assume the flue gasses from the fire actually goes right around these three tubes as it goes up into the chimney? I find it interesting that my fireplaces do not have these three tubes. I do have intake vents on the sides with discharge vents further above the fireplace, but not the three tubes that are directly exposed to the fire/flue gasses. I'm sure Superior and Heatilator had many different models with slight differences, any guess which brand/model mine may be?

Now, If I want to put an insert into this "heatform" firebox, do I need to find in writing something from Superior or Heailator (or whatever brand/model my firebox is) that states it is OK to put an insert in the firebox? That seems tough as high efficiency fireplace inserts weren't around in the "heatform" days so I doubt they would mention it in any manual. Or is it a given since I have a masonry chimney around the metal firebox an insert is by default OK, just like putting an insert into an all masonry firebox? As a side note, am I the only one who finds it odd that it's ok to light an actual fire, roaring good if I so desire, in a fireplace (masonry, metal firebox, ZC, whatever) but then it may not be OK to put an insert in? It seems lighting an actual fire in the firebox would have to be more dangerous than putting an new insert in and lighting a fire in it. Maybe I'm missing something.

Lastly, I'm struggling to find an insert that fits. I'm leaning strongly toward a non-catalytic type insert as it seems to me from reading, the catalytic burnout zone is the most finicky/high maintenance part of the fireplace. The last thing I want is my fuel savings to go right back into recharging some catalyst or maintaining a new fireplace insert. So my size limitations are two fold, one, my hearth only stick out 17.5" from the outer face of the stone, and two, the firebox is only about 20" deep (measured from outer face of stone) and at the 20" depth spot the height is only 17.5". (17" back height is 21.5" and 15" back height is 23.5") The height limitation is due to the back wall of the metal firebox which slopes up and forward toward the front of the fireplace. So, specifically, where is the 16" hearth extension measured from? The front face of the stone? The closing/inner surface of the door? The outer surface of the door? I'm so close it makes a big difference in my case. Anything easy I can do to meet the hearth extension requirement if the hearth as is is a few inches short? Some inserts have mantle clearance requirements (clearances seem to vary much from insert to insert, another detail I find weird), anything easy I can do to meet this requirement to open up my insert possibilities?

I think that summarizes my questions for now. I apologize up front for the long and maybe wordy explanation/questions. Any feedback is much appreciated.

Happy burning.
 
Now, If I want to put an insert into this "heatform" firebox, do I need to find in writing something from Superior or Heailator (or whatever brand/model my firebox is) that states it is OK to put an insert in the firebox? That seems tough as high efficiency fireplace inserts weren't around in the "heatform" days so I doubt they would mention it in any manual. Or is it a given since I have a masonry chimney around the metal firebox an insert is by default OK, just like putting an insert into an all masonry firebox? As a side note, am I the only one who finds it odd that it's ok to light an actual fire, roaring good if I so desire, in a fireplace (masonry, metal firebox, ZC, whatever) but then it may not be OK to put an insert in? It seems lighting an actual fire in the firebox would have to be more dangerous than putting an new insert in and lighting a fire in it. Maybe I'm missing something.
Well to start yes you can put an insert in there but you may need to cut some to get the liner in correctly that depends on the insert and the box. Also the fact that you have rectangular i am assuming 7x11 flue tiles means you will either need to go with an oval liner or remove the old tiles in order to get insulation in. As far as the safety thing first off your chimney is most likely not up to code as is so it could be unsafe to burn now. But burning in an open fireplace is very different than in a stove. Stoves are burnt for much longer periods of time and at much higher temps than an open fire in a fireplace.
 
bholler,
Thanks for the reply. The fireplace I'm looking at putting the insert in has a square flue that is straight up from the firebox to top of chimney. It's pretty large, I think when I measured it the inside dimensions were close to 11" x 11". As far as the code thing goes, I assume that if a fireplace is installed per code at the time of installation it gets "grandfathered" in for use as long as it remains in good condition? I know for electrical stuff many old homes electrical wiring is NOT up to modern codes, but people are still allowed to run current through the wires due to "grandfathering" clauses. Are chimneys and fireplaces different? If you are not allowed to use a wood burning appliance unless it meets the most recent code it becomes a big gamble to spend much money on any stove or fireplace as code could change and it would become "illegal" to use. I do agree that a person has to use some common sense and decide if it is safe to use an older fireplace/stove depending on what code has changed and how safe the old code was or was not.
 
I stuck an Osburn Matrix insert into my heat-o-lator heatform fireplace it worked great. I did have to cut the throat section a bit so the liner would fit... used a sawzall, diablo blade and some earplugs.
 
The 16" hearth requirement is measured from the front of the stove door to the front edge of the hearth. If the hearth needs to be extended it may not be a big deal. A picture of the current setup will help us visualize what you are starting with.

Some inserts are adjustable for depth. What are the fireplace opening dimensions?
 
Thanks for the reply. The fireplace I'm looking at putting the insert in has a square flue that is straight up from the firebox to top of chimney. It's pretty large, I think when I measured it the inside dimensions were close to 11" x 11". As far as the code thing goes, I assume that if a fireplace is installed per code at the time of installation it gets "grandfathered" in for use as long as it remains in good condition? I know for electrical stuff many old homes electrical wiring is NOT up to modern codes, but people are still allowed to run current through the wires due to "grandfathering" clauses. Are chimneys and fireplaces different? If you are not allowed to use a wood burning appliance unless it meets the most recent code it becomes a big gamble to spend much money on any stove or fireplace as code could change and it would become "illegal" to use. I do agree that a person has to use some common sense and decide if it is safe to use an older fireplace/stove depending on what code has changed and how safe the old code was or was not.
ok so a square 11 x 11 will work just fine with an insulated liner. As far as code goes yes you can use a non compliant fireplace your insurance company would be the only one who could do anything about that. As far as being grandfathered there really is no such thing when it comes to fire code you either meet code or not. You are not required to bring things up to code until you work on them like when you put an insert in then it must meet all modern codes. And by the way in 79 it is very possible there was no local code or inspectors so who knows how it was built
 
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