FLOOR FURNACE LOCATION
Choose a central location such as a hallway but where occupant traffic is minimal and where there is at least 18 inches of room from two adjoining sides of the grill to the nearest wall so that occupants may pass without stepping on the grill. See Figure Number 1.
Bedroom Bath Kitchen
Vent Pipe
Thermostat
Bedroom18” Minimum
Living Room
FIGURE 1
WALL
8”Minimum
FIGURE 2
Give consideration to available air for combustion, location in relation to chimney or vent system, thermostat location, clearance under floor, clearance to combustibles, and heat circulation. Any open foundation is unacceptable as wind can cause pilot outage and reduced efficiency. Keep furniture, drapes, doors, and other combustible materials at least 12 inches from the edge of the grill. Never locate the floor furnace closer than 8 inches to a wall and never in a corner. See Figure 2.
Two adjoining sides of the floor furnace must have a minimum clearance of 18”. See Figure 1.
FLOOR |
| FLOOR |
JOIST |
| JOIST |
| FLOOR | 6” Minimum |
| FURNACE | |
|
| |
|
| Draft |
|
| Hood |
Ground | 6” Minimum |
|
Level |
| |
|
|
FIGURE 3
After selecting a location in the home, go beneath the floor and check the position of the floor furnace in relation to joists, supporting columns, electric wires, water pipes and walls. There must be a minimum of 6 inches clearance between the top of the draft hood and floor joists. There must also be at least 6 inches clearance between the bottom of the floor furnace and the ground. See Figure 3.
In order to find the location beneath the floor it may be necessary to drill a 1/16 inch hole through the floor approximately in the center of the selected floor furnace location to use as a reference point when measuring under the floor.
FRESH AIR FOR COMBUSTION AND VENTING
Adequate air for combustion and venting must be provided. Any reduction in the necessary amount of fresh air can result in an oxygen starved flame that emits Carbon Monoxide (C.O.) an odorless, colorless gas that can cause serious injury or death. A ventilated crawl space will usually provide enough fresh air. However, you must check to see that there is 1 square inch of free area of ventilation opening for each 1,000 BTU’s input of your floor furnace. EXAMPLE: 50,000 BTU floor furnace 1,000 = 50 square inches. If another gas burning appliance such as a water heater is installed within the same crawl space or basement, add the B.T.U.’s of the other appliance to those of the floor furnace before calculating the total ventilation needed. EXAMPLE: 50,000 B.T.U. floor furnace plus 40,000 B.T.U. water heater equals 90,000 B.T.U. 1,000 = 90 square inches. To compensate for the loss of square inches of ventilation due to the use of louvers, grills, or screens add approximately 50% to the square inches calculated. Screen all openings with mesh not less than ¼ inch to prevent animals or insects from entering the crawl space.
All type “B” vents shall extend in a generally vertical direction with offsets not exceeding 45 degrees, except that a vent system having not more than one 60 degree offset may be allowed.
Any angle greater than 45 degrees from the vertical is considered horizontal. The total horizontal run of a vent plus the horizontal vent connector shall be not greater than 75 percent of the vertical height of the vent.
Any offsets used should be as far above the drafthood as possible to allow a venting action to begin before any restriction is encountered.
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