Reznor LDAP Unit Installation Manual - Manual (Page 4)

Form I-LDAP, P/N 207733R6, Page 4
Confined Space:
A space whose volume is
less than 50 cubic feet per
1000 BTUH of the installed
appliance input rating
Combustion Air
Requirements for a
Heater Located in a
Confined Space
FIGURE 1 - Definition
of Confined Space
and Required
Openings for
Combustion Air
(3)
(3)
(1)
(1)
(2)
(2)
Confined
Space
2.2 Combustion Air This heater must be supplied with the air that enters into the combustion pro-
cess and is then vented to the outdoors. Sufficient air must enter the equip-
ment location to replace that exhausted through the heater vent system. In the
past, the infiltration of outside air assumed in heat loss calculations (one air
change per hour) was assumed to be sufficient. However, current construc-
tion methods using more insulation, vapor barriers, tighter fitting and gasketed
doors and windows, weather-stripping, and/or mechanical exhaust fans may
now require the introduction of outside air through wall openings or ducts.
The requirements for combustion and ventilation air depend upon whether the
heater is located in a confined or unconfined space. An “unconfined space”
is defined as a space whose volume is not less than 50 cubic feet per 1000
BTUH of the installed appliance. Under ALL conditions, enough air must be
provided to ensure there will not be a negative pressure condition within the
equipment room or space.
Do not install a heater in a confined space without providing wall openings
leading to and from the space. Provide openings near the floor and ceiling for
ventilation and air for combustion as shown in FIGURE 1, depending on the
combustion air source as noted in Items 1, 2, and 3 below.
Add total BTUH of all appliances in the confined space and divide by figures
below for square inch free area size of each (top and bottom) opening.
1. Air from inside the building - openings 1 square inch free area per 1000
BTUH. Never less than 100 square inches free area for each opening. See (1)
in FIGURE 1.
2. Air from outside through duct - openings 1 square inch free area per 2000
BTUH. See (2) in FIGURE 1.
3. Air direct from outside - openings 1 square inch free area per 4000 BTUH.
See (3) in FIGURE 1.
NOTE: Venting
requirements may
affect location.
Consult requirements
in Paragraph 6.3
before making final
determination.
For best results, the heater should be placed with certain rules in mind. In gen-
eral, a heater should be located from 15-40 feet (4.6-12.2 M) above the floor.
If two or more heaters are installed in the same room, a general scheme of air
circulation should be maintained for best results.
Suspended heaters are most effective when located as close to the working
zone as possible, and this fact should be kept in mind when determining the
mounting heights to be used. However, care should be exercised to avoid
directing the discharged air directly on the room occupants.
Partitions, columns, counters, or other obstructions should be taken into con-
sideration when locating the heater so that a minimum quantity of airflow will
be deflected by such obstacles.
CAUTION: Do not locate the heater where it may be exposed
to water spray, rain, or dripping water.
WARNING: A Model LDAP power-vented heater is designed to take combustion air
from the space in which the heater is installed and is not designed for connection to
outside combustion air intake ducts. Connecting outside air ducts voids the warranty
and could cause hazardous operation. See Hazard Levels, page 2.
2.0 Heater
Location
(cont’d)