Installing a wood insert into Heatilator Mark 123

[legohat]

I currently have a Heatilator mark 123 installed in my home (1970's) that I would like to upgrade to a wood insert and use it as a primary heat source for my house, at least the upstairs (~1200 sq ft) living area. I am having a hard time determining if the existing zero-clearance stove can have an insert installed inside of it. The dimensions of the brick opening are 33" wide by 30" tall. The dimensions of the metal box are 31" wide, tapering back to 22" wide, 16.5" deep and 24" tall.

I was hoping something like this would work the (broken link removed to http://blazeking.com/EN/wood-princess-insert.html) would work

 

[begreen]

Welcome. I believe the Mark 123 is a masonry form. If this is the wood burning version, it should be ok for an insert. Based on the stove dimensions it looks very close. The Princess insert is 25.5” (w) x 23.5” (h) x 13”(d)

 

[BKVP]

Verify a UL127 listing for the fireplace if it is a ZC. If it's masonry, it will not matter.

Fun project!

 

[willoweep]

The Heatilator Mark 123 is a factory built zero clearance fireplace that was popular in the 1970s. They have a 9" solid pack insulated chimney that is quite heavy. I have installed hearth stoves in front of them with insulated 6" liners. All the usual warnings about installing inserts into zero clearance fireplaces need to be followed, of course.

 

[begreen]

Thanks willoweep. Heatilator's website mentions this line as a masonry form, but the Vega manual from the 70's shows it is a ducted ZC fireplace. I stand corrected. So far I have not found a UL127 rating in the manual.
http://www.heatilator.com/Owner-Resources/Install-and-Owners-Manuals.aspx

 

[legohat]

Thank you all for your responses. So far I am under the impression that it should work but will need some professional advice.

I had one fireplace installer tell me that it was absolutely not possible to install an insert in this ZC fireplace. He said that the fireplace was never designed to take the heat produced by modern inserts. From what I understand the Heatilator takes cold air in from the room through a vent at the bottom and circulates it behind the metal firebox to keep it cool and prevent combustion of the surrounding combustible framing (wood 2x4). Will the insert need to maintain this airflow to keep the framing cool enough or will the insert simply not get that hot for it to be an issue? A freestanding option (Jotul F 3 CB) installed in front of the ZC was suggested. What are the pros/cons of going this route? I have had my heart set on the Blaze King because of some very satisfied friends that have been burning wood for a long time and never experienced burn times and efficiencies compared to the catalytic burning in the Blaze King.

I am of coarse waiting on a second opinion from another certified installer, but I would like to have as much information as possible before he comes.

Does anyone know where you find this UL127 rating and what exactly this rating signifies? I have also scanned through the manual that begreen shared a link to but did not find anything.

 

[begreen]

I couldn't find any UL127 certification. I would call Heatilator's and Blaze King's tech support and ask if installing an insert in this unit is possible. FWIW, I disagree with the first installer's opinion. The outside shell of an insert is going to be much cooler than a direct fire in the fireplace.

An F3CB would be much less a heater than the Princess Insert. It has a small firebox and will only provide a 3-4 hr period of significant heat on average. For a freestanding stove you will need one that has a rear exit flue that clears the lowest point. If the curtain frame can be removed to increase height, that would help. For a rear exit catalytic stove take a look at the Woodstock soapstone stoves.

 

[Grisu]

Is not UL 127 simply the standard that covers fireplaces? Since the Mark 123 says UL listed on the back it should have been tested to that standard. The question is if that standard is still the same more than 30 years later. Asking Heatilator about installing an insert in the fireplace would be the right think to do. I would also inquire if it would be ok to cover up the bottom air vent. I doubt it (and probably would not do it even when they say it can be done for additional peace of mind). Make also sure your fireplace can hold the additional 400 lb of weight of the Princess plus the wood you want to put in.

A freestanding stove would certainly be the safer route although looking at the design of your fireplace I can understand why you want to go for an insert. Still, does not hurt to take a look at the Woodstock stoves. The Fireview could be sufficient for 1200 sqft if the house is not too badly insulated. Btw. Warm air always rises. Either stove or insert will only heat the level it is on and maybe additional levels above. You won't be able to heat the "downstairs" with a stove/insert unless you install one there.

 

[thechimneysweep]

I normally try to avoid me-too postings, but something about this discussion compels me to toss in a couple pennies:

Willoweep is correct, the Heatilator Mark 123 is a zero-clearance fireplace.
And Grisu is correct, UL 127 is the testing standard for zero-cans.
And BeGreen is correct, with an insert installed, the Mark 123 will never again be subjected to the temperatures created by the open fires it was designed (and listed) to withstand.

The two cents worth:
There has never been a Heatilator zero clearance fireplace that wasn't listed to the UL 127 standard.
You won't likely get official approval from either company about the proposed Heatilator/Blaze King marriage, mainly because the products haven't been tested together (there isn't even a testing protocol for inserts in zero clearance fireplaces). This doesn't mean an individual who is willing to follow the instructions in the installation manual and get the finished project inspected and approved by the local code authority can't carry on without official approval from the manufacturers: we've been installing inserts in Heatilator Mark 123's for decades, without a single mishap.

 

[Bartlett]

I have a Mark 123 Heatilator Fireplace with the Mark 700 chimney and had been interested in adding a wood stove insert the last three years. I have all of the original paperwork for the fireplace/chimney and parts. I have been getting the run around trying to see if this can be done. At first I was told by multiple heating installation personnel that my chimney could not be used with an insert contrary to what I researched. This year I am being told that I can (including by my town building inspector). This year I have also been getting mixed information regarding whether an insert can be added. The dimensions of the internal space of the fireplace appear to be 22(H) x 17.5(d) x 48(w) in the front and it tapers to 22(h) x 17.5(D) x 28.5(w). I say appears to be, because I haven't been able to get the last screws out of front bottom attachment that helps keep logs from rolling out of the fireplace. I have a very contemporary house, so the insert I was looking at was the pacific energy neo 1.6. I would like a contemporary looking insert that will give the best heat output. The Ellite 33 by fireplace xtradonaire would work if I was able to determine that the depth was 17.75". It seems like I should confirm with my local building inspector to ensure they will approve an insert. Any comments or recommendations including any insert recommendations? I get an error trying to upload a picture of my fireplace.

 

[thechimneysweep]

First, you need to verify that the size and clearance requirements for the Neo 1.6 will be met. Print the page at (broken link removed to http://www.chimneysweeponline.com/cpacneo16ins.htm) and take it to the fireplace with a tape measure.

Next, pop the rain cap off the chimney and determine whether your chimney is solid pack (two nested pipes, sealed over at the top with little V's stamped into the sealer cap), or air-cooled (three nested pipes with air between the layers, open at the top). You're going to need a stainless liner extending from the Neo to the top of the chimney in any case, but if you have Heatilator's air-cooled triple wall, you'll also need to insulate.

 

[Bartlett]

Thanks. The Neo 1.6 (30 w x 16.25 d x 20 h) is the only contemporary looking insert I could find that fits the dimensions of the fireplace. The Mark 700 Metalbestos model ss chimney I believe is air cooled, but I don't currently see it mentioned in the instructions/manual. It has a 14 " outer id with a 9 " inner id. I will try to go up and check it today as long as the rain holds off. I did find a reducer/increaser on line that goes from 9" to 6". I am assuming one would be needed, but since I don't do this for a living I could be incorrect. I also saw on line that the chimney liners have insulation surrounding them, so are you recommending another layer of insulation outside of the one that surrounds the liner (if I confirm that mine is air cooled)?

 

[thechimneysweep]

You won't need a reducer/increaser, because you're going to install a 6" liner up the inside of the existing chimney. The transition/seal is made by the top plate. The liner we sell (Forever Flex) is uninsulated, but they offer an insulation blanket for use where required (as is the case with manufactured air-cooled chimney).

 

[bholler]

I ma not going to start an argument again but i am with installer number one due to reasons that can be found by looking at other insert in zc fireplace threads. We will not install any inserts in zc units.