Combustion & Ventilation Air - Williams 3501522A Owner's Manual

FIGURE 4 - ENCLOSED MODEL
FRONT VIEW ENCLOSED MODEL SHOWN
FIGURE 5 - GAS PIPE SIZES
NATURAL GAS PIPE CAPACITY - BTU/hr.
(INCLUDES FITTINGS PIPE SIZE)
LENGTH
OF PIPE
FEET 1/2"
20
92,000
40
63,000
50,000
60
PROPANE GAS PIPE CAPACITY - BTU/hr.
(INCLUDES FITTINGS PIPE SIZE)
LENGTH
OF PIPE
FEET 1/2"
20
189,000
40
129,000
103,000
60
Combustion & Ventilation Air
WARNING: Danger of property damage, bodily
injury or loss of life. The furnace and any other fuel-
burning appliances must be provided with enough fresh
air for proper combustion and ventilation of flue gases.
Most homes will require that outside air be supplied into
the heated area.
The high cost of energy for home heating has brought about
new materials and methods used to construct or remodel
most current homes. The improved construction and
additional insulation has reduced the heat loss and made
these homes much tighter around windows and doors
so that infiltrated air is minimal. This creates a problem to
supply combustion and ventilation air for gas-fired or other
PIPE SIZE
3/4" 1"
190,000 350,000
130,000 245,000
105,000 195,000
PIPE SIZE
3/4" 1"
393,000 732,000
267,000 504,000
217,000 409,000
fuel burning appliances. Any use of appliances that
pull air out of the house (clothes dryers, exhaust fans,
fireplaces, etc.) increases this problem and appliances
could be starving for air.
In addition, these energy measures mean that your home
will retain more water vapor or a higher relative humidity.
High humidity, especially during cold weather, may be
damaging to buildings because condensation forms on
windows and inside walls.
The combination of a tight energy efficient home with
the use of exhaust fans, fireplaces, clothes dryers, and gas
appliances result in more and more air being drawn from
the house until fresh air may be sucked back into the
house down a furnace flue or fireplace chimney. Carbon
monoxide can be the result. Carbon monoxide (CO) is a
colorless, odorless gas produced when fuel is not burned
completely or when the flame does not receive sufficient
oxygen. Automobiles, charcoal, wood fires and improperly
vented or air-starved coal, oil and gas furnaces or other
appliances can produce carbon monoxide.
BE AWARE OF THESE AIR-STARVATION SIGNALS:
1. Headaches, nausea, dizziness.
2. Excessive humidity shown by heavily frosted windows
or a moist "clammy" sensation.
3. Fireplace smoke fills the room or will not draw.
4. Furnace flue backs up.
AIR REQUIREMENTS
The requirements for providing air for combustion and
ventilation are listed in the National Fuel Gas Code NFPA
54/ANSI Z223.1 (in Canada: CAN/CGA B149). Most homes
will require that outside air be supplied to the heated area
by means of ventilation grilles or ducts connecting directly
to the outside or spaces open to the outdoors such as attic
or crawl space. The only exception is when the furnace
area meets the requirements and definitions for an
unconfined space with adequate air infiltration.
WARNING: Danger of property damage, bodily
injury or loss of life. The furnace and any other fuel-
burning appliances must be provided with enough
fresh air for proper combustion and ventilation of flue
gases. Most homes will require that outside air be
supplied into the heated area.
All air openings and connecting ducts must comply with
the following:
If the furnace is installed in an area with another gas
appliance(s), the total input rating of all appliances
must be considered when determining the free area
requirements for combustion and ventilation air openings.
Ducts must have the same cross-sectional area as the
free area of the openings to which they connect. The
minimum dimension of rectangular air ducts must not be
less than 3-inches in length or height.
9
VENTED ROOM HEATERS