Can inserts be installed ZC fireboxes?

[elkimmeg]

Withoul all the codes and Ul listings infront of me I going to take a stab at this issue basically using my memory

I may latter look up the official requirements

This is a complicated question that the pursheser has to do his homework on
Some manufactures like Travis Industries have actually tested certaint stoves in common ZC fireplace installations and list the ones tested
where their insert can be installed Many manufactures only list their inserts to be installed in NFPA 211 compliant masonry fire boxes
meaning no amount of retrofitting shy of building a masonry fireplace will comply. There may be ZC inserts that can be boxed around that as long as the clearance distances are met they could go in a ZC opening Finally some ZC can be installed only in a zc that has a specific UL listing ( I have to look up that listing)

On top of that the ZC has to be in good shape not rusted out. One can not remove refractory facings unless to repair them.
Cracked facings are a sign of fatigue and dissqualify that fireplace from installations One can not modify the fire place in any way except to remove the damper
Cutting into the damper frame for a liner also poses issues It can be done only if that frame is not part of the structual support. All hope is not lost as I believe
there are approved ZC replacement enclosures Welding plates over rusted out cracked areas is not acceptable besauce these are signs of system wide
deterioration IE the metal the plate is welded to, has already been compromised

As noted in prior post there also may be a weight support issue. Naturally if I see deterioration in the metal fire box, that usually indicates other areas probably are not up to snuff

A lot of times the chimney leaked causing the ZC to rest out. usually if there is wood support under that stove there is a chnce it is damaged as well from water leak..

After everything is sorted out with the fire box. then there is issues with moldings and floor protection and mantel issues many times that slate tils infront of the ZC is only that one layer on a wood under layer of flooring no thermal protection what so ever

then there is the Venting issues ZC have two standards to meet UL 103 or UL103HT Ul103 is the 1700 degree rating UL 103 ht or HT 2100 are the
same and can be used for wood stove usage
providing the cross-sectional codes are met

The real problem is dealing with Ulo 103 1700 drgree vent ,usually the cheaper air cooled dead air space insulation In this case there are two options rip it out and install class A ht 2100 /UL103ht Some how the 2100 degree rating has to be met. The other option is to install a liner the liner alone does not carry the 2100degree requirement till it is insulated with 1/2 ceramic blanket insulation there is another UL listing for that UL 1777 But more works needs to be done onc cannot just run the right liner up that chimney and place a capup there
that air circulation space cannot be blocked with the new termination cap and flange I do know Homesaver makes an approved tested liner system with a termination cap that is designed to protect the otiginal air space from weather and allow air circulation (I know Sp too lazy to clean it up) A complete linner system tested and approved that addrewss all venting issues of UL 103 1700 degree air cooled pipe.

Like I said this post is to start the discussion rolling. In many cases it is easier and safer to tear out that old system and stare with a new approved enclosure and class A pipe
and install a n insert approved for ZC installations In noway can an insert approved for masonry installations can be installed.

Be real carefull purchasing used inserts for ZC installations Too much involved to guess it think it might work only to find out it can't even be installed there

 

[jtp10181]

I have people suggest to use the original cap from the ZC system and run the liner up to it and suspend it at the top of the ZC chimney system. This would keep the cooling system in tact and protect everything from the weather. I have also talked with someone who has been to many fire scenes that were believed to be caused by this cooling air being blocked.

Elk, do you have any more info on this HomeSaver system? They don't really have any product info on their site that I could find. Sometimes we might need to replace an insert in a ZC unit where the original cap is long gone and not available anymore. I am interested in how to construct something to keep the cooling air in tact and still keep rain out.

 

[BrotherBart]

Elk, do you have any more info on this HomeSaver system? They don't really have any product info on their site that I could find. Sometimes we might need to replace an insert in a ZC unit where the original cap is long gone and not available anymore. I am interested in how to construct something to keep the cooling air in tact and still keep rain out.

Here are the installation instructions.

http://www.hartshearth.com/Download/FactoryBuiltLinerAdaptorSu.pdf

 

[rdrcr56]

In this liner set up what is the difference if the liner is insulated and runs up the old 13 in. metal chase, is suspended by the old cap and some how the old cap is enclosed, vs. running up brick and mortar chimney with an enclosed cap at the top ( no air flow).

 

[jtp10181]

Most prefab chimney systems are designed to have an outer chamber that allows cooling air to flow through it, keeping the outer shell cooler. This is how it is tested and listed. If you block off that cooling air and create a stagnant air chamber it will heat up and could overheat the outer shell. Over time this could dry out nearby combustibles and start them on fire.

The masonry chimney is designed to be safe without an outer cooling air chamber.

 

[elkimmeg]

In this liner set up what is the difference if the liner is insulated and runs up the old 13 in. metal chase, is suspended by the old cap and some how the old cap is enclosed, vs. running up brick and mortar chimney with an enclosed cap at the top ( no air flow).

The difference is dealing with the temperature ratings a NFPA compliant Masonry chimney and flue system, has the needed masonry mass/ thickness to isolate the heat from the combustiables Therfore does not have to be brought up to HT 2100 standards again that is a good condition cNFPA compliant chimney not a masonry one with cracked clay linere cracked bricks and missing motar joints that type of chimney requires Ul 1777 i/2 " insulated liner to be brought up to the heat standard and clearance to combustiables standards

Air flow is not a designe element of a masonry chimney although the clay liner is suposed to have 1' air space around it

Now if you have a 13 " 1700 degree metal cooled system it is only designed for that appliance period and not for any adapation to any other appliance /stove To adapt it one has to upgrade it to both HT 2100/or UL103 HT and still not block the air passagess or the air cooling space. Some ZC were installed with Class A HT standards in this case the liner is more to do satisfing cross-sectional area codes, than upgraging the existing chimney classification.. Really I do not know if air cooled chimneys were rated HT standards most were only 1700 degree standards,

This is also assuming what is there is in good condition. I start requiring condition reports on chimneys over 15 years old.. There are times when during the permitting process, We are told something, that In the field looks entirely different. We have the right to require even resind a permit if we discover unsafe condition, called field corrections. Naturally the evidence is quite glaring to resind a permit.

 

[webbie]

I think we already have a little wiki article about it, and we have discussed this one many times before.

We also found that a lot of installers, shops and even building officials were not paying any attention to the codes and standards on this one. For instance, MSG said installing "non zc approved" stoves in their area of Co. was normal and approved by the local inspector!

https://www.hearth.com/econtent/index.php/wiki/Convert_Prefab_Fireplace/

Short and sweet - only approved inserts or (very rare) hearth stoves can be installed into metal pre-fab fireplaces, and then only with a full liner in the vast majority of cases. There are some exceptions to the lining, but only newer ZC fireplaces with 2100 degree tested chimney and 8" flues. Most ZC's being converted are older and cheaper units.

Even in these cases, the "fit" is often difficult.

I think this entire issue can be put into one or two paragraphs and that all the long threads and posts confuse the issue - sounds like we are in Yeshiva (Jewish school) or Bible Study.....

 

[elkimmeg]

I have people suggest to use the original cap from the ZC system and run the liner up to it and suspend it at the top of the ZC chimney system. This would keep the cooling system in tact and protect everything from the weather. I have also talked with someone who has been to many fire scenes that were believed to be caused by this cooling air being blocked.

Elk, do you have any more info on this HomeSaver system? They don't really have any product info on their site that I could find. Sometimes we might need to replace an insert in a ZC unit where the original cap is long gone and not available anymore. I am interested in how to construct something to keep the cooling air in tact and still keep rain out.

The problem here is you are mix matching components of different systems and loose the complete system approvals I agree that your system of allowing the air flow to work does
meets most of the requirements

Again another discussion occured about using caps did that viod the entire liner listing I say no because draft enhancement caps are substituted all the time But to truelly meet all the test standards of the listing all listing components must be used. In the case of Homesavers tested and listed system, there cap is part of the system approval I know I posted the entire detils of the system testing and cap details before less tha 2 months ago maybe some could dig up that post..

Fortunately I do not deal often with ZC conversions to inserts most chimneys here are masonry It really is a confusing issue which we are trying to straight out here once done wiki it so the discussion has been done with all viewpoints logged in No I do not have all the answers but enought to get the ball rolling here It seems to be a major issue with inserts everyweek anouth insert is going in ZC fireplaces I know for a fact some of out best dealers that post here have installed an insert in a ZC that was only listed for masonry fireplace applications.
I had an off forum discussion with him about that..

that leads me to another discussion who should pull the permit? Code and law states a permit is required prior to comessencing of any work. Naturally if the installer is unlicenced the the Home owner can still pull the permit under homeowner exemptioms. They agree to take full responsibility of the installation and can hire unlicenced un insured installers. or licenced ones

Should a question come up during and inspection that is discussed with the name on the permit . If aninstaller name happens to be on the permit that discussion is between him and I first before the homeowner gets involved. Liken it to a lockerroom discussion where the instller and I reach an agreement to solve that question Done this way reputations are not tarnished and makes for much better inspector relationships in the future He knows I was not our to undress him or his workers infront of the customer Also the final signoff is issued to the permit holder if he is owed any money he is holding the permit his bargining chip to be paid

The home owner holding the permit just found out they hired clowns and that installer' questionable work has been exposed in in the greatest light does nothing for his reputation Now the homeowner has to beg to get that guy back to correct the issues the same guy responsible for the issue and did less than compliant work Even worst for the homeowner he already paid him in full.

Reality is the person purchases a stove and schedules an installation the installers are real busy this time of year and do not have time to pull permits but go ahead and do the installation an installation that is not permitted, then the homeowner reads Hearth,com and figures out he better get a permit. Most inspectors will issue the permit But they have code backup and grounds to require that stove's removal it should never been installed prior to a permit everbody does this hoping all goes well The installers here are just as guilty They should have never done an unpermitted installation in the first place They know they did it wrong but cover themselves withcheck in habnd leaving and saying better get a permit Boy do these situation get sticky when I discover a insert only approved for masonery fireplace installations sitting in a ZC. I love when The dealer and installer start pointing a finger at me as I'm the one wrong the bad guy because he has made this very instulation hundered of times without an incident. I'm the bad guy for being the only one to read the manufacture's manual? Ok laugh but this happens all too often

 

[kd460]

Just to toss a little info in: For those with Heatilator systems, this cap provides the proper air flow for that 1" space as well. Can't seem to find the UL rating of it or the sl300/sl1100 pipe that it works with, but is another choice. This post is NOT to be confused with any statement in reference to "not using a liner". Don't want the info to be misinterpreted! KD

Sorry, forgot to include link:

http://www.heatilator.com/products/accessories/termcaps.asp

 

[karl]

Elk to answer your question from another post.


The summit manual says, "Your insert is designed to be installed into a masonary or factory built zero-clearance firelplace." A few lines down it says," The factory built zero- clearance fireplace and its chimney must be listed per UL 127 or ULC S610 standards." Can you tell me what these standards require?


I am here asking questions and listening in particular to your advice because I have no faith what so ever in the building inspectors in my town. I plan on pulling a permit and having it inspected but I honestly don't care what they have to say as long as they give me the stamp of approval which I'm sure they will. I want my installation to be Elk approved. When I asked what the problem was with a metal fireplace, it was genuine question.

I am fortunate in that I have a fireplace in my unfinished basement as well. It was installed at the same time as the fireplace in my living room and appears to be identical to it as well. It is completely exposed. I can stick my head in between the metal box and the block walls of the basement and look all around in there. Here's what I see.

First it says Benefire 43 on the label and says to use 13"x13" tile. It also says something about more heat less smoke on the label. I don't know how thick the metal is but I can assure you they don't make 'em like this anymore. The house was built in 1964 and the fireplaces were installed then. It is a double wall metal box. It appears as though there are several knock outs on the side of the metal box. They have not been knocked out. The box is built in to concrete block. And to say it's built in, is really a stretch. Set in is more like. I will get some measurements for you tomorrow, but I it appears to have about a 2 foot gap between the concrete block and the metal box. That is on the sides. The back, I'm not sure about. I'll measure it tomorrow. It appears to be about a foot. The metal box has no bottom in it and is setting on fire brick. I don't know how thick this brick is but there is an ash box in there that is maybe a foot deep and the bottom of it is brick as well. The top of the box tapers to a square and the tile is set on it. This is the flue tile that goes all the way to the top of the chimney. What surpised me is that I see subflooring going right up to the tile. This is the basement chimney. I am putting the insert in my living room, One floor up. I will check and make sure I don't have anything like that going on in it. I don't think I do. It's a one story house, so there's no sub floor above it. I do know the concrete block goes from the basement to the top of the chimney. I can see it in the attic and see it going through the roof. It must go all the way to the top of the chimney. They would have had to have had something to attach the granite exterior block to.

My question, and it is a sincere one, made by a person who really wants to learn something is: Why would you have to remove the metal box from a fireplace to install an insert? As far as clearances go. Here is What PE requires

Minimum Clearances to Combustibles

Adjacent sidewall 8.5"
Mantel 21.0"
Top Facing 21.0"
Side facing (1.5in. extension) 8.5"


Here is what I have. PLEASE NOTE This to the metal box not the block

Adjacent sidewall not applicable
Mantel 19" to the paneling of which I'm going to remove 3 or 4 inches of and replace with marble.
Top facing Same as above PLEASE NOTE the paneling comes down in front of the metal box. And has concrete "transom" of some sort, supporting the rest of the block up through the roof. The box itself is 45" inches high This gives me 2 inches more than the insert requires to the top of the box.

Side facing. I have 6" on each side at the front of the insert and 10" at the back.

So according to PE's requirements. I have more than enough room from the top of the insert. I am 2" short on the sides at the front of the insert and 2" over their requirement towards the back sides. The back of the insert they don't list a requirement for but I have 7 inches there. Remember this is to the inside of the metal box only and it is double walled with about 4 more inches of air gap between to the two pieces of metal. I then have one to two feet between the box and the concrete block. Then the thickness of the block to any combustibles. I will be running a 6" insulated stainless liner in a 13" tile. That will give 3.5" of air gap between the liner and the tile. The tile is enclosed in concrete block as well.


Elk, does it sound like I can put this insert in the fireplace? Do I have to take the metal box out? The flue tile is stacked on top of it and I'm sure supporting it.

I want it safe, but the bottom line is I have $450,000 replacement cost insurance on a house with a market value of a little over $200,000. So if it's inspected and I get out alive. I'm not going to cry about losing the house anyway.

 

[jtp10181]

Just to toss a little info in: For those with Heatilator systems, this cap provides the proper air flow for that 1" space as well. Can't seem to find the UL rating of it or the sl300/sl1100 pipe that it works with, but is another choice. This post is NOT to be confused with any statement in reference to "not using a liner". Don't want the info to be misinterpreted! KD

Sorry, forgot to include link:

http://www.heatilator.com/products/accessories/termcaps.asp

Thats just ZC prefab chimney caps... has nothing to do with liners. Anyone with SL1100 or SL300 chimney is going to have one of those cpas already. The only time someone would need another is if the chimney was relined at the cap was removed and trashed, and the air flow was restricted.

 

[kd460]

Liners is what I am talking about also. My install (factory heatilator zc with the sl300 pipe) DID NOT have the tr344 cap when I purchased the house new. When I installed my ZC APPROVED insert with the 316ti liner, I could have just as easily installed the cap that came with the liner kit, creating the problem being discussed here. It seems the st375 cap that came with the house had a tendency to let creosote build up due to the sudden cooloing of the chimney smoke when it reaches the open "cage" of the cap. It builds up on the underside or the cap and the creosote flakes off and then falls back in between the air space of the sl300 pipe. Not a good thing, especially over long term. So the natural thing to do would be to use the cap that comes with the liner kit to prevent this and eliminate the st375 cap all together.

However, finding info on here, prevented me from making that mistake. I learned enough here (on similiar discussions to this one) that I needed to vent and not trap that 1" space which certianly would have happened if I used the cap that came in the liner kit. I could not rely on the inspector as he spent all of 2 minutes in the house, never looking at chimney cap. I have learned alot since then, and the tr344 cap eliminates this problem all together for my paticuliar install.

So my point is, heatilator prefab fireplaces are pretty popular in new construction, and if someone like myself does a similiar upgrade to an insert, (for those with the heatilator sl300 pipe), who put a liner in it for a zc approved insert in there heatilator prefab fireplace need to be aware and at least have the above option. KD

 

[webbie]

Elk to answer your question from another post.


The summit manual says, "Your insert is designed to be installed into a masonary or factory built zero-clearance firelplace." A few lines down it says," The factory built zero- clearance fireplace and its chimney must be listed per UL 127 or ULC S610 standards." Can you tell me what these standards require?

First it says Benefire 43 on the label and says to use 13"x13" tile.

Karl, I think you arre confusing yourself by talking and thinking about ZC fireplaces.

Your fireplaces sounds like a Bona-fide masonry fireplace with a "heat-form" inner liner instead of firebricks. This internal heavy box was designed to have a wood burning fire built right inside it, so it is certainly able to take the tiny amount of heat coming off the PE insert!

See: https://www.hearth.com/econtent/index.php/wiki/Heatform/

If this is correct, and you have a masonry structure with an orange flue tile...with metal firebox set into place, then simply install the insert using the MASONRY fireplace instructions. Off the cuff, that means install it with a 6" stainless liner to the top and a block-off plate.

 

[Gooserider]

Elk - right now this discussion seems to be focussing on the idea that there are just two types of fireplaces - Masonry units and ZC's. I have no issues with the idea that there are lots of restrictions on what can be put into a ZC unit, and limits on how it can be modified.

However, it seems like there is a third option that doesn't seem to have been addressed, but which sounds from their descriptions like what some of our users have - Karl in particular comes to mind. This is the metal "heatform" type fireplace - which I know exists because I grew up with one in my parent's summer cottage. This is a unit that consists of a metal box inside a masonry fireplace, it is NOT a ZC unit, the fireplace still meets all the clearance issues of a masonry unit, but has this metal box inside it that is intended as a heat recovery system of sorts - the box is double walled, and connects to vents at the top and bottom, with the idea that heat from the fire would heat the metal walls and get a convection current going to send heat out into the room that would otherwise go up the chimney.

What I thought I'd seen before is that these heatform units were basically considered to be the equivalent of masonry units, and you could do anything in one of them that you could do in a masonry fireplace - I believe this is even in the Wiki as well.

Now I see you and Englander Mike saying that you can't put any insert into a metal heatform - and I'm feeling confused, and I think some of the other folks here are also being confused by this.

Can you clarify?

Thanks,

Gooserider

 

[karl]

Craig, I think you misread what I typed, or perhaps I wasn't clear about it. The PE manual says it's approved for zero-clearance fireplaces and the metal box in my fireplace says it's a Benefire. The PE manual doesn't say anything about Benefire. I thought all along that I had a Bona-fide masonary fireplace. The reason I posted the question in the other thread about removing the metal was because I found it to be unnecessary and Elk was saying it had to be done. PE lists minimum clearances to combustibles and the metal is not combustible, so why do I need to remove it?

This is from the other thread

ME:
Why would the metal fireplace have to come out? I’m puting a Summit insert in my fireplace. My house is 43 years old and has concrete block for the fireplace and chimney. The chimney is lined with tile and the fireplace has a metal shell in it. I figured that I could just install a block off plate, a liner, and then slide the insert in. Is this not the case? The bottom of my fireplace is masonery, but the sides and top are not. The damper is part of this whole metal structure.

Elk:
Karl is you summit listed for ZC installations?
I’m starting a new post to get the ball rolling on this issue it is occuring on the forum quite frequently


I looked at the link you provided and it is very similar to what I have. I definately have the retangular damper and terracota flue tile. So are you saying I'm good to put this insert in and that the only clearances I have to worry about are the clearances from the insert to anything that is combustible?