Guidance and direction around current fireplace upgrade (built in heatilator)

[cabinwarmer]

Good Day, I am hoping to get some thoughts and guidance around upgrading this "old style zero clearance" fire place. I believe this is some type of older heatilater installation.

Fireplace opening is 50"w x 34"H. The unit is 39" deep from the back to the front of the hearth. The ceiling is 70" from the top of the hearth. The outside chimney structure is @ 15' tall from the floor to the top of the stone chimney.

Inside the chimney seems to have some firebrick tiles and then a steel lining? The flue opening is rather small at 4-5" only.
My hope is to install a hearth warmer stove, if possible. An insert would be a second choice. The heating area is an old stone farm house, two story with steps and floor vents. @325 sq' for floor = 650sq' total with low ceilings. Insulation value is average.

Thanks in advance for your help,

Dave

 

[vbu]

Trying to replace old metal lined fireplace

I assume it's either a heatilator or heatform but I don't know the difference. Is it safe to remove the metal walls inside, it isn't structural I assume. What will be behind the metal? Best ways to remove metal inside? What would it take afterwards to put a stove inside, just tile it? Thanks

www.hearth.com

This is a similar thread. I've posted some pictures in there of what I did to mine. I cut the double wall and back out so I'd have space to run a liner and have enough space for the insert. My insert is going in this Saturday. Let me know if you have any more questions! I'd have a professional check out if you can do the same thing to yours like I did to mine

 

[begreen]

The damper area will need to be cut to make an opening slot for the liner. A decent ~2 cu ft insert will make a very nice improvement for heating.

 

[cabinwarmer]

Thanks guys......vbu, I will go through your previous post, thanks. Both of you are looking at an insert, no way a smaller stove wood fit? Ceiling too low for a stove?

 

[EbS-P]

Your opening is bigger than mine. A stove could fit in there nicely. You just are more limited in your choices. An insert might be a more efficient heater. You have options. Just gonna throw out jotul 602 as it’s sized for the sq footage. I Don’t like the small glass on it in that big of an opening though. I’d say get an F400 like mine but they aren’t available and it’s probably a bit oversized but but if you want larger glass the stove generally will be bigger. I would set a budget and start shopping for a couple styles of stove you like.

Evan

 

[vbu]

Thanks guys......vbu, I will go through your previous post, thanks. Both of you are looking at an insert, no way a smaller stove wood fit? Ceiling too low for a stove?

A stove may fit, no idea honestly. Never looked into it because we liked the look of an insert better

 

[Pennsyltucky]

I am currently doing the same in this thread: https://www.hearth.com/talk/threads...-install-ongoing-project.183673/#post-2464596

I was able to raise & widen my opening quite a bit, with your hearth being monolithic you don't have that ability without some serious demo work that could create structure issues.

If you go freestanding look for an ember protection only stove that will sit on the hearth with rear-exit & front loading. I'd want to sit the stove in front of the opening as much as possible, then use ember protection on the floor if it's needed.

I am putting a second stove in next year in this room below, its a similar setup and I'm going with the Jotul F 500 Oslo or equivalent as it fits in the opening and is rear exit. I have the same type of metal double-wall heatilator.

 

[cabinwarmer]

I would have to take a closer look at the exit point. I do not like the rear exit so much as then an angel fitting is required to get up the chimney. I agree with the front loading, for sure. Maybe a top exit free standing that would only require a partial "sit back" into the existing stone. The tape measure is next. I may have a local chimney sweep take a look at removal of the steel liner.

 

[Pennsyltucky]

My opinion, leave the liner in. The heatilator will function with the freestanding stove and help spread the heat. I removed mine and it was a colossal pain for minimal size gain.

Typically the flue is at the very rear of the fire box, this means a top-exit stove is going to have to sit all the way back in the firebox to vent. I thought the same and ended up with rear-vent for this reason, I wanted to stove in front of the opening and not inside it.

 

[cabinwarmer]

I would like to leave the steel liner, why not, as you suggest. Could clean it up and paint. I think just the flue closure needs to be cut out to allow for the flex pipe. The opening is still tight, seems to be 5 inches. So, even some of the steel supporting the closure may need to be "notched" for the pipe. Agree, looking to have the stove out as much as possible. I have just installed my GM 60, and was trying to see if the very same stove would fit. Having identical stoves would be a plus, but not a requirement. Does the flex connect directly to the stove or is there a connector piece? Reason I ask, I would try to stay away from the 90 degree elbow. Just always fills up with unwanted soot. Unless there is a clean out type elbow from the stove to the flex pipe.

 

[Pennsyltucky]

Use a reciprocating saw (saw-zall) to cut out the damper and open the top of the metal insert into the flue. A bi-metal blade will rip through the liner without issue.

Nothing wrong with a rear-exit Tee with cleanout. I'd Check out Rockford Chimney supply, I'm in PA and they ship out of Scranton, I got most items in 2-3 days.

 

[cabinwarmer]

Is it not common to put some kind of a baffle in to seal up the chimney around the new flex pipe?

 

[bholler]

Use a reciprocating saw (saw-zall) to cut out the damper and open the top of the metal insert into the flue. A bi-metal blade will rip through the liner without issue.

Nothing wrong with a rear-exit Tee with cleanout. I'd Check out Rockford Chimney supply, I'm in PA and they ship out of Scranton, I got most items in 2-3 days.

They only ship from scranton if you buy olympia chimney products. Rockford is just a retailer.

Sawzalls work on some. Others a grinder works better it depends upon how thick it is how hardened it has gotten etc.

 

[bholler]

Is it not common to put some kind of a baffle in to seal up the chimney around the new flex pipe?

Yes a block off plate should be installed

 

[Pennsyltucky]

Is it not common to put some kind of a baffle in to seal up the chimney around the new flex pipe?

Yes, you should absolutely seal this area. I used a piece of HVAC Duct Panning in a rectangle with overlapping half circle cutouts around the flex pipe, then stuffed unfaced insulation up there and put the panning in with tapcon screws.

Unfaced Fiberglass insulation is safe up to ~1000F, it's a noncombustable.

 

[bholler]

Yes, you should absolutely seal this area. I used a piece of HVAC Duct Panning in a rectangle with overlapping half circle cutouts around the flex pipe, then stuffed unfaced insulation up there and put the panning in with tapcon screws.

Unfaced Fiberglass insulation is safe up to ~1000F, it's a noncombustable.

It is not rated as non-combustible and 1000 is not high enough temp rating for this application. Mineral wool or ceramic wool is needed.

 

[Pennsyltucky]

It is not rated as non-combustible and 1000 is not high enough temp rating for this application. Mineral wool or ceramic wool is needed.

Per MFG site their unfaced fiberglass insulation is noncombustible: https://pdf.lowes.com/dimensionsguides/047563706420_meas.pdf
"Classified non-combustible when tested in accordance with ASTM E 136"

I used this product around a double-wall insulated flex liner at the base to seal base of chimney. Is that PDF wrong, I have no problem pulling it and using rockwool, what do you think?

 

[bholler]

Per MFG site their unfaced fiberglass insulation is noncombustible: https://pdf.lowes.com/dimensionsguides/047563706420_meas.pdf
"Classified non-combustible when tested in accordance with ASTM E 136"

I used this product around a double-wall insulated flex liner at the base to seal base of chimney. Is that PDF wrong, I have no problem pulling it and using rockwool, what do you think?

It is only non-combustible to the rated temp which is 1000 degrees I know fiberglass will not actually burn. But it will melt and smoke. Which is why you should use insulation with a high enough temp rating.

 

[begreen]

Unfaced Fiberglass insulation is safe up to ~1000F, it's a noncombustable.

A flue liner can see temps over 1000º. That's why mineral or ceramic wool is used instead.

 

[AlwaysStacking]

Per MFG site their unfaced fiberglass insulation is noncombustible: https://pdf.lowes.com/dimensionsguides/047563706420_meas.pdf
"Classified non-combustible when tested in accordance with ASTM E 136"

FYI ASTM E136-19A applies 750C to the test specimen for 30 minutes. You can do your research on what temperatures the insulation will see but given that there are other industry standards it would be more appropriate to follow those.

The title of ASTM E136 was changed by the committee because they didn't like the word "Noncombustible".

 

[cabinwarmer]

Thanks guys....all good info I will utilize. Question: Will ~15 ft be enough length for my 6 inch flex pipe flue? I am thinking it should be. I am leaning towards a new 2020 hearth stove.

 

[cabinwarmer]

Getting a quote from one of the local shops on doing this installation to verify if I want to do it myself our not. The quote had 2 ply flex pipe, as recommended in this forum, I have asked for. better flex liner product for the requite. Also, no blocking plate was included, as the dealership was thinking insert instead of free standing. I believe, the Hearthstone GM40 would fit into this area nicely. Opening is 34H x 50W. Back to from of hearth is 41". Back of firebox across is 39". Damper opening 5' which will be cut for flex pipe. Floor to ceiling is 70", rather low ceiling. Approx 15' chimney currently with slate cap that would be removed.

 

[cabinwarmer]

update, :
Finally had a pro sweep to take a look at my conventional fireplace. He has determined that the fire box has rusted out down behind the shelf area, and there is grout damage in the flue between the tiles. He has told me that the fireplace is not safe to burn at this point. So that has rulled out getting it repaired. Trying now to understand if wood or LP gas is a better solution. I did get a quote on adding 6 inch flex pipe, if I wanted to proceed with a smaller wood hearth stove or insert. I am researching LP gas but do not like the idea of the non-vent models. I want to exhaust out of the house when lit.

 

[begreen]

The quote had 2 ply flex pipe, as recommended in this forum,

The consensus has been to avoid 2 ply liners. They have a high failure rate, often starting right at installation. A 15' liner will work for most inserts, but there can be confounding factors that will affect draft outside of just the liner length.