Single Pipe Venting; Vent Requirements; Combustion Air Supply - Viessmann Vitodens 200-W WB2B Series Installation Instructions Manual

Vitodens Rigid and Flex Venting Systems Installation

Vent Requirements

Combustion air supply

This boiler requires fresh air for safe operation and must
be installed in a mechanical room where there are provisions
for adequate combustion and ventilation air.
There are no provisions available on the Vitodens boiler to
interlock it with an external combustion air blower.
The Vitodens boiler is suitable for sidewall, as well as
vertical venting using field supplied venting material. The
Vitodens 100-W, 222-F and 200-W boilers are approved
for direct exhaust (non-sealed combustion) operation in
both, horizontal and vertical arrangements.
Provisions for combustion and ventilation air must be made
in accordance with CAN/CSA-B149.1 or .2 Natural
Gas Installation Codes (for installations in Canada) or in
accordance with sections for Combustion and Ventilation
Air, of the National Fuel Gas Code, ANSI Z223.1 or
applicable provisions of local codes (for installations in the
U.S.A.) Always use latest edition of applicable standard.
Follow local codes to properly isolate the vent pipe when
passing through floors, ceilings and roof.
Whenever possible, install boiler near an outside wall so
that it is easy to duct fresh air directly to the boiler area.
Refer to national codes for duct sizing. Round ducts may
be used.
The boiler must be vented and supplied with combustion
air and exhaust vents as described in this section. Ensure
the vent and combustion air supply comply with these
instructions.
WARNING
Failure to provide an adequate supply of fresh
combustion air can cause poisonous flue gases to
enter living space, which can cause severe personal
injury or loss of life.
Single Pipe Venting (Room Air Dependent)
The boiler location should never be under negative pressure.
Exhaust fans, attic fans, or dryer fans may cause air to be
exhausted at a rate higher than the air can enter the structure
for safe combustion. Corrective action must be taken to
ensure enough air is available. Never cover the boiler or
store debris or other materials near the boiler, or in any way
block the flow of adequate fresh combustion air to the boiler.
If boiler is installed in a confined space (a space with a
volume of less than 50 cubic feet per 1000 Btu/h of gas
input for all fuel burning equipment) or building layout
is unusually tight, adequate air for combustion must be
provided by two openings: one located about 6 in. below
the ceiling, the other about 6 in. above the floor.
When communicating directly with the outside, each
opening must have a minimum free area of one square
inch per 2000 Btu/h of gas input. When all combustion air
is provided by openings in doors, etc. to adjoining spaces
having adequate infiltration, each opening must have a
minimum free area of one square inch per 1000 Btu/h of
gas input, but not less than 100 in
You must know the free area of louvers used to cover
up the combustion and ventilation openings in closet
installations. If you do not know the free area, assume
20% for wood louvers and 60-75% free area for metal
louvers. When using louvers, the openings have to be made
larger. For example, a free 14 in. x 6 in. opening becomes
a 14 in. x 10 in. opening for a grill containing metal louvers.
CAUTION
Do not store chemicals containing chlorine or other
corrosive materials near the boiler, such as bleach,
cleaning solvents, detergents, acids, hair spray,
spray cans, paint thinners, paint, water softener salt,
perchloroethylene, or carbon tetra chloride.
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