Jack SUPER SJ125, Owner'S Manual

Page: 20 / 56

FURNACE LOCATED IN CONFINED SPACE
When the furnace is in utility room, install two open grilles.
Place them in a wall or door opening to the rest of the
house. One grille will supply combustion air.
Locate it near the floor. The other grille is for ventilation.
Locate it close to the ceiling. Each grille must have a free
area. It should be not less than one square inch for each
1000 BTU/hr. of the total input rating of appliances in
confined space.
FOR EXAMPLE: Your furnace is rated at 150,000 BTU
per hour. The water heater is rated 30,000 BTU per hour.
The total is 180,000 BTU per hour. You need two grilles,
each with 180 square inches of free opening. Metal grilles
have about 60% free (open) area. Therefore, you need
two metal grilles with 300 square inches each of louvered
area. The height should be about half the width.
SIZE
1/4” MESH
SCREEN
BTU
WOOD
LOUVERS
BTU
METAL
LOUVERS
BTU
3-1/4 X 12 INCH
8 INCH ROUND
8 X 12 INCH
8 X 16 INCH
144,000
200,000
382,000
512,000
36,000
50,000
96,000
128,000
108,000
150,000
288,000
384,000
BTU Per Hour Input*
* Based on opening covered by 1/4 inch mesh screen, wood or metal louvers.
FRESH AIR DUCT CAPACITIES
Fresh air duct capacities for duct supplying fresh air
Plan Your Installation
20
CAUTION:
Be sure the installation of furnace
meets the required clearances to
combustible materials.
(See page 17)