1. Welcome Hearth.com Guests and Visitors - Please enjoy our forums!
    Hearth.com GOLD Sponsors who help bring the site content to you:
    Hearthstone Soapstone and Cast-Iron stoves( Wood, Gas or Pellet Stoves and Inserts)
    Caluwe - Passion for Fire and Water ( Pellet and Wood Hydronic and Space Heating)

Help with ID on a Fireplace

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by will1349, Mar 28, 2013.

  1. will1349

    will1349 New Member

    Joined:
    Mar 28, 2013
    Messages:
    7
    Loc:
    Shoreview, MN
    Hi,

    I just moved into a 1976 split entry home in Minnesota 6 months ago. I want to install an insert into the old origional prefab fireplace, but I can't identify what kind of fireplace it is. The writing is so faded, but I can barely make outsomething like Model: 8F-36... I can see that it is a "zero clearance fireplace." I can also see that it has the UL logo in the upper left hand corner. The only other thing that I can make out is Minnesota which is writen in small letters in the very bottom righthand corner of the metal plate. I really appreciate any help you can give me with this. I'm also trying to figure out who built the house from the city.

    On another note, I have already purchased a Century CW2500 insert. I'm hoping to be able to install this insert because it seems like a great value. I also don't want to burn my house down, so if it comes to it I can return this insert for something else. I talked with the manufacturer and he basically said that this unit is only tested for masonry fireplaces, but that figureing out if my old prefab unit is able to have an insert installed into it would be the most important next step. I should have done more research first, but the insert was on sale so I went for it. I do plan on installing a 6 inch s.s. liner to get the proper draft, and to help with making the chimney safer.

    The old prefab seems to be in decent shape. It has a 8" inner, 10" outer chimney that seems to have insulation between the two. I don't know for sure, but it doesn't sound hollow when you tap on it. The chimney only has around .5 inches of clearance to the exterior sheathing of the house right at the top of the fireplace. Another note is that the fireplace doesn't have much clearance to the exterior sheathing of the home. In some places it may even be touching on the sides. Pink fiberglass was shoved all around the unit between the wood and the exterior of the metal box (I'm assuming the heating contractor that the builder hired did this, or maybe the insulator thought it was a good plan to help stop drafts from the outdoors.) If the prefab unit was taken out and the new Century sits where it is in my picture there would be over 20 inches of clearance to combustibles on the top, 8-10 from the back corner going diagonally back and to the sides, and over 20 if you go straight back. I've talked with my local building official, and he didn't seem to know that much about the details... I'm very glad that I found this website as there seem to be very knowlegable people on here. Thanks for any input.

    Attached Files:

    Helpful Sponsor Ads!





  2. dougand3

    dougand3 Minister of Fire

    Joined:
    Oct 16, 2008
    Messages:
    776
    Loc:
    North Alabama
    Welcome, Will. Those prefab builder's boxes weren't designed for high temps - just an ambiance fire. The 8"/10" chimney - probably air cooled (doubt there is insulation in between pipes) isn't rated for wood stove/insert heat. You need Class A chimney rated for 2100*F for short periods. And the CW 2500 needs a 6" chimney - yours probably wouldn't draft well, even if safe. And inserts are really for total masonry FPs.
    If this was me...I'd pull prefab and chimney out and examine closely what you have, adapt hearth and alcove (as needed for CTC), install proper Class A chimney and exchange insert for freestanding stove. That's a ton of work but being safe with a 1500* fire is really needed.
  3. Mr A

    Mr A Minister of Fire

    Joined:
    Nov 18, 2011
    Messages:
    597
    Loc:
    N. California
    @dougand3, that is good advice. You have the opportunity to do whatever you want with the space. Pull out the zero clearance, you will find a closet like space behind it. Tile it, bricks, etc. Run proper flues. You could put in a big or small free standing stove.
  4. mellow

    mellow Resident Stove Connoisseur

    Joined:
    Jan 19, 2008
    Messages:
    3,087
    Loc:
    Salisbury, MD
    The Century is out, it is not rated for ZC installs. I would take it back and use that money towards ripping out that prefab and making it an area for a free standing stove, you will be much happier with the end result.

    I would say that is an old Majestic 36" fireplace, but that is a shot in the dark.
  5. will1349

    will1349 New Member

    Joined:
    Mar 28, 2013
    Messages:
    7
    Loc:
    Shoreview, MN
    Thanks for the input! I will have to either return the stove or sell it online (I think they are going to get me for a restocking fee.) Is there a good forum out there for selling inserts? I'm not sure what my new plan is yet, but I will be sure to post my plan here first before I buy anything again!!

    Another question: Is is safe to use any prefab insert without reinstalling the glass doors? I would assume so as long as I get some kind of screen to block sparks. I might have a few small fires in the old prefab before tearing it out this summer.
  6. mellow

    mellow Resident Stove Connoisseur

    Joined:
    Jan 19, 2008
    Messages:
    3,087
    Loc:
    Salisbury, MD
    You could get one of those folding fireplace screens in front, that should be ok for a basic burn.

    List it on CL and see if you get any offers.
  7. FyreBug

    FyreBug Minister of Fire

    Joined:
    Oct 6, 2010
    Messages:
    771
    Loc:
    Kitchener, Ontario
    No where do we state any of our inserts are not rated for ZC installation. Here's our standard recommendation:

    It is possible to install a wood insert into an existing factory-built zero-clearance fireplace. However, there currently exists no UL or ULC standard specific to that type of conversion. The first thing that must be verified is that the factory-built zero clearance fireplace is listed (it must be certified by a competent certification body such as Omni or Warnock Hersey). It must be suitable for use with solid fuel and nothing in the owner’s manual must specifically prohibit the installation of a fireplace insert. When in doubt, check with the fireplace manufacturer. The installation of the zero-clearance fireplace MUST be thoroughly inspected by a professional in order to ensure that it still meets the manufacturer’s specs and code conformity. The chimney must be of at least 1" (25 mm) larger in diameter to accommodate a required continuous stainless steel liner running from the flue collar to the top of the chimney termination.

    Never remove parts that serve to insulate the zero-clearance fireplace from combustible material. Only readily detachable parts that are easily replaced, such as damper parts, screens, and doors, are to be removed from the fireplace. These parts must be stored nearby and available for retrofit if the insert is ever removed. Removal of any parts which render the fireplace unfit for use with solid fuel requires the fireplace to be permanently labelled by the installer as being no longer suitable for solid fuel until the removed parts are replaced and the fireplace is restored to its original certified condition. Furthermore, any air vents, grilles, or louvers that serve to create an air circulation pattern around and outside the zero-clearance fireplace shall never be removed.
    tfdchief likes this.
  8. will1349

    will1349 New Member

    Joined:
    Mar 28, 2013
    Messages:
    7
    Loc:
    Shoreview, MN
    Hi Fyrebug,

    I have read that statement about 100 times in the owners manual, and I still can't say that I understand it completely. Can someone help me understand what this means "The installation of the zero-clearance fireplace MUST be thoroughly inspected by a professional in order to ensure that it still meets the manufacturer’s specs and code conformity." How do you define a professional? I have talked to many professional contractors, and the building official and I don't feel like they know enough about the details to this discussion to tell me for sure my house won't burn down. When you say manufacturer's specs and code conformity are you refering to the specs of the existing prefab, or of the Century unit. I havn't seen any specs from Century for this type of install.

    For those that say it for sure won't work, how do you know for sure that an insulated liner in the chimney wont be sufficient? I have a hard time believing that my normal fire is going to get the chimney up above 1700*. I also don't understand how it won't be fine if my ctc above the stove will be over 18 inches when the acceptable clearance to a shelf above the unit in a typical masonry fireplace install is 17". And along with the 18inches I have the prefab as a barrior. I understand that these are two completely different senarios, but it still seems like plenty of room for the air to cool down.
  9. STOVEGUY11

    STOVEGUY11 Feeling the Heat

    Joined:
    Feb 12, 2008
    Messages:
    424
    Loc:
    SOUTHERN CT
    Hi Will,
    I saw in one of your pictures that the steel plate is still in the Pre-fab fire box. Can you get a manufacture and model number off of it. Try cleaning it off. As FyreBug said, you need to make sure that the pre-fab box is certified to except a solid fuel burner into it. There have been so many manufactures of these pre-fabs over the years. Some still in business, as well as many that are not. With out determining what the fireplace is, I am sorry to say, but your dead in the water. Those pre-fabs use air cooled chimney systems, only rated at 1,700 degrees. Solid fuel, such as your new insert needs a chimney tested at 2100 degrees.
  10. begreen

    begreen Mooderator Staff Member

    Joined:
    Nov 18, 2005
    Messages:
    46,743
    Loc:
    South Puget Sound, WA
    If the insert is installed with an insulated liner, isn't the air cooled chimney somewhat of a moot point?
    tfdchief likes this.
  11. STOVEGUY11

    STOVEGUY11 Feeling the Heat

    Joined:
    Feb 12, 2008
    Messages:
    424
    Loc:
    SOUTHERN CT
    I would agree with that personally to a certain extent. What I have found locally around here, is that some town inspectors will approve it, and others will not. Have not done an insert to a pre-fab in about a year and a half for this reason. But the pre-fab box must still be identified as tested for the application of the insert. Too many gray areas when it comes to inserting a stove to a pre-fab. Not a big fan :confused:.
  12. begreen

    begreen Mooderator Staff Member

    Joined:
    Nov 18, 2005
    Messages:
    46,743
    Loc:
    South Puget Sound, WA
    will, is there any possibility of extending the hearth a bit so that you could have a freestanding, rear-exit stove on the hearth?
  13. Dave A.

    Dave A. Minister of Fire

    Joined:
    Mar 17, 2013
    Messages:
    617
    Loc:
    SE PA
    Not an expert, but I think the concern is making sure that the original protections of the ZC fireplace haven't been compromised by any modifications needed to install the insert. And whoever is making that determination knows what they are doing and can be relied on -- that's my take on it anyway.

    That seems to be meaning the ZC fireplace specs.
  14. will1349

    will1349 New Member

    Joined:
    Mar 28, 2013
    Messages:
    7
    Loc:
    Shoreview, MN
    Thanks everyone for helping sort this out.

    I tried cleaning the metal plate and then using a flashlight from multiple angles I was barely able to see model:8F-36. I can't determine the manufacturer though. I should be able to figure out who built my home from the city hall, and then I can hopefully determine what fireplace was installed (if the builder is still around.) Otherwise, I may have to go knock on some neighbors doors and see if they have the same kind of fireplace.

    That's what I would have thought too.

    I'm starting to see this. Will there be less grey area when I determine what my prefab is?

    Certainly... is an option. I'm sure it would be hard to find the brick that would match, but I could slap down a different looking hearth.. Are you thinking that I would run a liner up the prefab chimney for this though, or are you thinking tear out the prefab and run new class A? I would rather not come too far into the room with the hearth as it isn't the largest area. What would be the difference between a free standing wood stove and the Century unit sitting on the current hearth in front of the prefab? The hearth would allow the insert to have 3/4 of the unit sitting in front of the brick front, while leaving 2-3 inches recessed into the brick opeing and 4 inches between the stove and the prefab. I don't know if this would work though, as the manual says I can only bring the Century out 8 inches in front of the brick front.
  15. begreen

    begreen Mooderator Staff Member

    Joined:
    Nov 18, 2005
    Messages:
    46,743
    Loc:
    South Puget Sound, WA
    The hearth could also be extended at floor level, maybe even flush with the existing floor deepending on your skill level. With a side-loading stove like the Woodstock Fireview you only need about 8" hearth in front of the glass.
  16. mellow

    mellow Resident Stove Connoisseur

    Joined:
    Jan 19, 2008
    Messages:
    3,087
    Loc:
    Salisbury, MD
    For something that is ZC rated I sure do see the word Masonry a lot in the user manual.
  17. FyreBug

    FyreBug Minister of Fire

    Joined:
    Oct 6, 2010
    Messages:
    771
    Loc:
    Kitchener, Ontario
    When referring to a 'Professional' we mean someone who has trade certification as per NFI, WETT or CSIA. They have insurance and when determining viability of installation they refer to the original MFG (builder box) manual & specs as well as inspecting the original ZC for any modifications that would render it unsuitable for this type of installation. Once this is done they may be able to issue a 'certificate' or written statement that in their opinion the unit is fit (or unfit as the case may be) for this type of installation.
  18. Dave A.

    Dave A. Minister of Fire

    Joined:
    Mar 17, 2013
    Messages:
    617
    Loc:
    SE PA
    Not putting down Century/SBI. But if you look at some other mfrs e.g. Travis (which I am not necessarily recommending) they make using a ZC fireplace with an insert a lot easier. Travis lists ZC fireplace mfrs they have cleared for use with certain of their wood inserts.

    You haven't given very much info about your heating requirements here, square footage and how much you plan to rely on this for heat, but having just replaced my Century with a much larger insert, you should realize that as reasonably priced as it is, unless your requirements are very low, the CW2500 may very well end up being too small for you.
  19. Dave A.

    Dave A. Minister of Fire

    Joined:
    Mar 17, 2013
    Messages:
    617
    Loc:
    SE PA
    Another thought. If you were to go into a hearth store looking at some other inserts explaining your situation, they often want to come out to examine your prefab just to see what they can put in it. In the process he might know just by looking which one you have.
  20. will1349

    will1349 New Member

    Joined:
    Mar 28, 2013
    Messages:
    7
    Loc:
    Shoreview, MN
    I'm wondering what the difference would be between the Century and other brands that are certified for certain prefab fireplaces when it comes to the chimney requirements? If I could use a different brand insert then isn't the whole chimney argument out the window? I guess I don't know for a fact that all solid fuel inserts need a 2100 degree rated chimney, but I would assume they are similar..

    As far as my heating requirements... I plan on using the insert mainly for heating my basement family room, and anything other than that would be bonus to save a little natural gas. The house is a 2000 Sq Ft split entry, and the family room downstairs is about 15 x 25. I don't intend to have a fire every night all night throughout the winter to heat the house. It would also act as a back up heat source to the furnace. I'm pretty sure that it would come close to heating the entire house especially after my air sealing and insulating job in the attic last fall. I tightened the home by 40% just by sealing up the attic! Makes it kind of hard to get my old prefab drafting without opening a window.

    I did find out who built the home, and who installed the mechanicals in the home. I will try to contact the hvac contractor tomorrow, but unfortunately the builder seems to be out of business.

    Thanks for the clarification on what you mean by "professional." If I reconsider installing this insert I would have a professional out to look the situation over for me.
  21. FyreBug

    FyreBug Minister of Fire

    Joined:
    Oct 6, 2010
    Messages:
    771
    Loc:
    Kitchener, Ontario
    This ZC "certification" for inserts theme keeps coming up... I dont know how else to say this folks... There is no such thing! CSA, ASTM, UL etc... certification bodies have not issued a standard, testing, protocol, papers etc... for this. Therefore no certifications. Nothing to certify to!

    If a particular MFG chooses to 'certify' their insert to certain ZC's, they are in fact stating "we will allow the installation of our units only in the following ZC's". They may or may not have conducted their own test under their own criteria to do so. Sometimes they do this for marketing reasons and sometimes for liability reasons.
  22. Will,
    I would recommend that you not speculate on the applicability of your fireplace for a woodstove insert retro-fit. Unless or until you can identify the manufacturer and get in writing confirmation that they approve and will assume liability for the proposed installation AND a certified service person inspects your installation and signs off that it was installed according to the manufacturer's instructions, don't install the unit. You'll spend a fair amount of time and money getting that far and I suspect the process will not allay your fears at the outset.
    Its not just the chimney that is exposed to more heat: There is a wood header and framing above the firebox that will likely pyrolize with the additional heat generated by a constantly fired insert.
    The question here shouldn't be, "what inserts are not rated for zc installs". The burden of proof should be on the zc manufacturers. How many of them do you think undertook the cost of safety testing, firing with an appliance manufactured by someone else, in addition to their own firebox?
    And inserts, like any wood stove are only tested for proximity to combustible walls to determine safe clearances to combustibles in a typical installation, (which in, a zc fireplace, is not). Beyond that is speculation.
  23. will1349

    will1349 New Member

    Joined:
    Mar 28, 2013
    Messages:
    7
    Loc:
    Shoreview, MN
    I don't really understand were your going with all of the speculation talk. I don't see what's wrong with a little speculation. All I'm trying to do is seek out a little information to help me decide which way to go. I honestly don't care as much about who takes the liability as I do about the potential that my house could burn down and take lives with it. Since it doesn't seem like I will be able to come to a concensus that the install will be safe I'm just going to take back or sell the insert and deal with a cold drafty pre fab for awhile. It seems like all of this would have been left up to a certified service pro, and since many of them that I have called don't install inserts into prefabs anylonger I just have to move on and come back with a new plan for next winter.

    Thanks for everyone's help. I wish my code official would have told me more up front before I bought the insert, but I guess he just told me what he knew so I can't blame him for that.
  24. dougand3

    dougand3 Minister of Fire

    Joined:
    Oct 16, 2008
    Messages:
    776
    Loc:
    North Alabama
    Will, don't feel bad about making a buying decision before needed facts are collected. I bought a Vogelzang Boxwood for my living room and THEN came on here to read about wood stoves. Yawzer!
  25. tfdchief

    tfdchief Minister of Fire

    Joined:
    Nov 24, 2009
    Messages:
    3,331
    Loc:
    Tuscola, IL
    Will,

    Applicability of putting an insert in a prefab is complicated and varied. Some inserts are recommended for zero clearance fireplaces and others are not. Some zero clearance fire places allow inserts and others do not.

    From a purely practical experience standpoint, I have found that the ones that start fires are the the ones with wood framing around them. Albeit, allowed for the zero clearance fireplace, but a big problem when the insert was installed (maintained heat for much longer periods of time than the fireplace). I can't tell where it is located, but I see wood framing in one of your pictures.

    As an example, we had a house fire that was started by a wood burning insert in a zero clearance fire place. It was installed in wood framing pretty much per the manufactures instructions and specifications. Then, stone was glued on the face of the hearth (wood framing). Then, in what appeared to be a masonry surround around the zero clearance fireplace, the insert was installed. It was burned for 2 1/2 years before it finally caught the wood framing on fire.

    As a personal example, I have a Majestic zero clearance fireplace that I installed in 1974. At that time, there was no such thing as "certified for wood burning inserts" However, when I installed it, I installed it with and ALL masonry front, no wood framing, drywall cavity (completely accessibly for inspection), and excessive clearance to combustibles, all the way to the roof, that were at the least, double the 2 inches required. (that would have been allowed per the installation manual, hence "zero clearance"). So, in 1982 when none of this was heard of, and no guidelines, I installed a Buck 26000 insert. I knew exactly every inch of the zero clearance fireplace installation and was confident that the insert was safe. It is connected to a 6 in SS liner inside the triple wall zero clearance fireplace chimney. I have burned it safely for over 30 years. The chimney does not EVER get anywhere near the temperature of the Class A chimney (Selkirk Super Pro) on my new EPA Hampton wood stove in the kitchen. In fact, it seldom gets more than lukewarm. Even if it did, there is nothing for it to catch on fire. All combustibles are too far away. And, on top of that, I have been to the worst, hottest chimney fire of my career, that occurred in the exact same chimney, installed per the manufacturers specifications, 2 inches to combustibles, through 2 stories, and it held......NO extension to the structure.

    Now, all that being said, I am not recommending that you put this insert in this fireplace. There is no way I could do that, at least not without looking at it in person. All I am saying is that codes and standards have to be written to protect everyone and all situations. Every installation is different, and even all certified components can be installed in such a way that they could be unsafe and start a fire. As an inspector, I have always taken the part of every code that says "approved" very seriously. "Approved" in the code not only means UL etc. but by the AHJ, that being me in my town. So, when I am very very confident, I sometimes approve things that may not have a formal stamped approval. I have seen some cases where the whole thing could melt down into a big heap on the floor and not start a fire.....so what is not to approve?

    Good luck with your situation. If you can verify the safety of the installation, go for it. If you can't, with out any doubt, tear it out and start over with something that you know every inch of. Then you will be able to go to sleep at night.

    Steve
    STOVEGUY11 likes this.

Share This Page