JUCA F-9A PLANNING
JUCA makes the F-9A series units in quite a variety of sizes. For commercial applications, we have supplied units with as large as 78" wide fireboxes. For some large houses (mansions???), we have made 60" wide by 40" tall units. However, our standard size unit is the most popular size fireplace in the USA, the so-called 36 by 28. Our standard firebox is physically 32" wide and 27" tall by 24" deep (all specifications subject to adjustment for specific applications). Since the firebox is surrounded by our high-efficiency heat exchanger chambers, the outside dimensions of the main body of a standard sized JUCA F-9A are approximately 43" wide by 47" tall by 26" deep.
There are three approved ways of enclosing the JUCA F-9A models.
In each case, all the dimensions specifically mentioned are appropriate for the standard-sized JUCA F-9A unit.
The first method, an entirely masonry enclosure, uses 4"
cinder blocks or other masonry right against or near the JUCA, surrounding
it and extending 8" above the body top. This makes the smallest
enclosure. Provisions must be made to leave passageways for the
blower connection on one side and the ducting connections on the
There are some applications that would normally be compatible with method 2 or 3 below, where there are nearby 2x4 studs present, but where the total space available is less than the width or depth necessary for those methods. In these situations, it may be possible to install a 56" tall barrier of 4" thick cinder blocks, on the sides and / or back of the JUCA F-9A, which reduces the necessary space to that of this method. In other words, such a cinder block barrier wall could be against the JUCA body and also against the wood studs, thereby reducing the required space to 4" total.
The INSIDE dimensions of either version of such a chase are 44" wide by 27" deep (from the finished room wall), with the surrounding cinder block barrier walls at least 56" tall.
The second method is to use wood 2x4 framing shielded by cement board and a 2" air space. This installation has been approved for a 7" total clearance (5" from the JUCA F-9A to the cement board, then two more behind the cement board to the 2x4s). The cement board is to extend to at least 8" above the body top of the JUCA.
The INSIDE dimensions of such a chase is 57" wide by 34" deep
(from the finished wall). This installation and the following one
generally provides enough space to allow the blower and ducting to be
inside the chase rather than exterior to it as suggested in the masonry
The third method is where wood 2x4 framing is exposed directly to the body of the JUCA. Even though the JUCA body NORMALLY is at a safe and comfortable 110-130°F temperature, it MUST be installed for a worst case scenario, one where the biggest fire possible is in the unit and the power goes off where the JUCA can no longer distribute the heat throughout the house. If all that heat stayed in the JUCA, the outer walls might eventually get pretty hot, hence these precautions. This installation choice involves a 15" clearance between the JUCA body and ALL wood structural members. If you have plenty of room available, the up-side of this choice is that you have PLENTY or room for the blower and ducting inside the chase.
The INSIDE dimensions of such a chase is 73" wide by 41" deep.
These drawings show the top, front and side view of a JUCA F-9A. The dotted lines on the top view drawing represent the chase dimension area for Method 2 or 3 Installations. The specific dimensions for each situation are described in the text above.
The Facing of the JUCA fireplace can be handled in countless ways. The actual structure in front of the JUCA body and surrounding the "snouts" by 7" must be all fireproof materials. Use metal studs or angle irons here (to support the facing backing board near the "snout" of the JUCA F-9A) instead of 2x4s. Use cement board instead of paneling or drywall in this area.
Since the JUCA has the 4" snout which joins the door assembly with the main body of the unit, there is room for a 4" thick masonry material here. It would be possible to use actual, full thickness standard facebrick as the fireplace facing. Thus, you could match the house's exterior or use a contrasting masonry design. Again, an alternate backing material arrangement would be to use 4" thick cinder block over the area in front of the fireplace. Then, this surface could be used as for the cement board backing board, so a veneer material could be used.
Such veneer material could be:
Once that fireproof structure is installed, the fireplace may use any style mantle or facing material, EXCEPT for a border of 7" around the opening itself. That ring around the fireplace opening MUST be brick or stone or marble or tile, etc. No wood right in that 7" border around the opening. Beyond the 7" distance, anything is allowed for an appearance material. The JUCA F-9A normally comes with a 4" snout around the door opening to allow space for using full-sized facebrick for this border. Veneer brick (Z-Brick, Brickettes, etc.), may also be used but an appropriate backing (of cement board) needs to space it out to be flush with the edge of the snout.
The blower (house air) intake mentioned above must draw house air. One option is to have it draw air from the cold air return system of the conventional furnace. If that is not practical, then it could draw through a decorative (cast-iron or brass) or functional (painted) grille. Location is rather optional but there are some advantages of having it near the ceiling, especially in a room with a vaulted ceiling. Hot air accumulates up there, anyway, so the JUCA would bring it down, heat it up, and push it out down where the people are, thereby evening out the warmth and improving occupant comfort level. If aesthetics do not permit this, the blower could draw from a grille in a different room or in a different area of the fireplace's room.. Make sure that the blower is accessible for future maintenance.
The warm air outlets locations are optional, too. Whether or not you send heat into a central ducting system, you should usually provide a couple of outlets (registers) in the room of the JUCA. Continuing the logic above, there is advantage in having these outlets at or near floor level for maximum comfort level and to avoid any cold drafts at floor level. With raised-hearth fireplaces, a convenient place is in the 'kick-panel' area just under the hearth. A couple of 4x12 supply registers or cast-iron or brass grilles usually look nice in the brickwork or stonework there. Optionally, by closing up the back of that chamber under the hearth, you could use it as a warm distribution box and just leave out some half bricks in that kick-panel area.
The resultant holes would act as warm air outlets without distracting from the brickwork motif. Screen should be installed at the back edge to keep kittens and such from getting inside.
The unit has heat shields under the firebox so that it can be installed on a plywood sub-floor if a 30" by 54" piece of sheet steel on a piece of cement board is installed over the plywood sub-floor.
(A 'combustible wall' in this context includes walls containing wood which is not exposed. For example, drywall over wood framing is considered a combustible wall. Thus these clearances are applicable to virtually all kinds of construction except masonry. Artificial thin brick (z brick, brickette, etc.) has little protecting ability unless there is an airspace behind it.