Homebuilt Fireplace Insert

[wireedm]

Just finished building my first fireplace insert. Kinda like the JUCA design.

1/16"-1/8" clearance all around w/1.5" spacing between 1/4" firebox and 3/16" outer shell. My fireplace is 34" wide and 27" tall and in looking at the standard model inserts I was losing too much burning/viewing area. The JUCA design had a straight firebox which lost a lot of burning/viewing area as well. I kept the original screen and glass doors that were on the fireplace and lost zero viewing area.

There is a 336 cfm fan on the right side from Grainger that has a switch/variable speed control on the wall next to where I sit during my favorite football game.

Took about a month to design and build in my spare time using mainly a plasma cutter, and Miller 350P mig welder. Having a machine shop doesn't hurt.

I have changed the top vents that look like "ears" with small 1" opening, 1/4" thick heavy vents. Looks much better and pushes the air out into the room.

By the way, the vents all ready in the brick around the fireplace were useless in case you wondered what they were.

It will run you outa there.

Let me know what you think.

 

[Ken05]

Its beautiful. Real nice fab work - I can see why you wanna show it off.

 

[havenodog]

Beautiful job. That is one nice insert. Kudos on the fabrication.

 

[sawinredneck]

IMPRESSIVE:jawdrop:

 

[PA Plumber]

Nice job. Good pics.

 

[RDT]

Very nice work .

 

[ericjeeper]

I like everything except

The wall registers on the top.. Find some brass grills and I will love it..
How do you hook it up to flex? or to a liner? Or is it meant to just sit in the opening and no liner?

 

[PA Plumber]

The wall registers on the top.. Find some brass grills and I will love it..
How do you hook it up to flex? or to a liner? Or is it meant to just sit in the opening and no liner?

I think the floor/wall corner registers were changed out for 1" openings.

Can't help with the rest.

 

[chowdozer]

Good looking workmanship and very nice!

 

[wireedm]

The wall registers on the top.. Find some brass grills and I will love it..
How do you hook it up to flex? or to a liner? Or is it meant to just sit in the opening and no liner?

Thanks for the generous comments everyone. There was definitely some sweat that went into this. It weighs about 400lbs.

Yes, as mentioned above I replaced those flimsy "ear" looking vents with pieces I made out of 1/4" plate. The opening is only 1" wide and about 12" long on each one. This 1" opening really throws the air out into the room.

I'll try and get some new pics up soon.

 

[user 19670]

That is some fine piece of work there.

:blob4:

 

[RAYINTOMBALL]

Sweeeeeeeet

 

[046]

SWEET!!!

very impressive job... JUCA's are super complex to duplicate. it's one big hollow heat exchanger made out of 1/4in plate.

 

[gtstang462002]

Would like to see some pictures of it operating....

 

[wireedm]

The wall registers on the top.. Find some brass grills and I will love it..
How do you hook it up to flex? or to a liner? Or is it meant to just sit in the opening and no liner?

Oops, I didn't finish answering your question earlier Eric.

I made this unit to just sit in the opening, so it really doesn't change the original fireplace function. Technically, I guess you could call this a fireplace heat exchanger, rather than a fireplace insert which usually has a compact, airtight firebox. Although the firebox was double-welded on the inside and out, it uses the original base of the fireplace that has an ash dump and is not completely airtight. There is also some air that gets through the small cracks in the glass and screen door opening. When I installed the unit I put 2" fiberglass insulation in between the brick wall and the unit before I squeezed it up against the wall. There is also the standard insulation behind the brass frame around the doors as well as at the bottom under the front frame to keep the air leaks at bay. The small slide damper at the bottom of the front frame works very well to control air getting to the flame but the small amount of air that does leak through keeps creosote buildup to a very minimum.

By the way, I have approximately half of the air baffled to go through the three 1.5" tubes at the top. The tubes don't create the hottest heat, but they are the quickest to heat up. Since squirrel-cage fans create a lot of volume but hardly any pressure, I do have the baffles about an 1/8" narrower than the space between the inner and outer shell so that there is less static pressure, keeping the volume as high as possible. This also helps keep the turbulence high which helps in the heat exchange process.

Hope this helps.

This has been a truly enjoyable project. I'll put some pictures of it in operation when I light a fire tonight. Maybe I can find something to make streamers out of to show the airflow in the top vents as well.

 

[allthegross]

FNA man great job

 

[wireedm]

Updated Pics

Okay everyone, here are some updated pics of the unit. As mentioned I changed the vents out for some 1/4" thick plate pieces I made. I believe they look AND function MUCH better.

I put some masking tape on top of the vents so you could see the amount of air coming out. Masking tape is fairly heavy to use for streamers, but that's all I had around.

Pictures are of the glass doors both open and closed.

 

[046]

looks like your internal wall angles are different from my JUCA insert.

when I close my door, flame noticeably increases as venturi effect kicks in.

your description of insert being a fireplace heat exchanger is a good one! where is your blower located? I've got electrostatic filter material wrapped around blower squirrel cage.

 

[wireedm]

looks like your internal wall angles are different from my JUCA insert.

when I close my door, flame noticeably increases as venturi effect kicks in.

your description of insert being a fireplace heat exchanger is a good one! where is your blower located? I've got electrostatic filter material wrapped around blower squirrel cage.

Yes, my internal wall angles are fit to the internal wall angles of my fireplace. The outer shell has about an 1/16" - 1/8" clearance to the original fireplace and the firebox is 1 1/2" offset in from that.

I was looking into getting the JUCA model, but I didn't want to lose any viewing area.

You're right, when I close my door the flame starts roaring if I have the damper at the bottom open, but I can get it to burn fairly slow if I have it open just a hair.

My blower is on the right hand side where the vent covers are. It is the same 336cfm unit that JUCA uses on their pancake version from Grainger. (I believe). The filter material is an excellent idea, I could put some just under the vent covers too!

 

[046]

air accelerating upon closing of door is what you want.

to prevent inside air/heat from going up chimney. ash dump has been converted to main fresh air intake.

after insert gets up to temps, note how much smoke comes out of chimney. if insert is burning very clean... you should see almost no smoke coming out during full operation. my chimney has little to no creosote buildup after two seasons of use for 100% heating of a 2500 sf single level home.

next up is adding a secondary burn system. newer epa stoves are more efficient by using a secondary burn system.

was getting ready to fab my own JUCA copy... out of frustration of not being able to get one for 3+ years. When JUCA finally agreed to make me one.

evidently several folks have successfully built JUCA copies. mostly due to non availability of JUCA units. basic constructions plans/information are posted on JUCA's site.