General Requirements - Viessmann Vitodens 200-W WB2B Series Installation Instructions Manual

Direct Venting (Two-pipe System)
Exhaust Vent/Air Intake Requirements

General requirements

The Vitodens 100-W, 222-F and 200-W boilers must be
located in such a way that the vent length is as short as
possible and that the vent can be routed as directly (and
with as few bends) as possible.
The minimum equivalent vent length is 3.3 ft. (1 m).
See tables starting on page 43 for maximum and minimum
vent lengths.
All products of combustion must be safely vented to the
outdoors. All Vitodens boilers vent under positive pressure
and are Category IV boilers.
WARNING
Failure to ensure that all flue gases have been safely
vented to the outdoors can cause property damage,
severe personal injury, or loss of life. Flue gases may
contain deadly carbon monoxide.
Viessmann recommends that the entire vent system be
checked by a licensed professional heating contractor at
least once each year following initial installation.
The stainless steel special venting system is completely
sealed when fully assembled. Locking bands or other
method of joining are used to reinforce the joints between
pipe and fittings.
The remaining space surrounding a chimney liner, gas
vent, or special gas vent or plastic piping installed within
a masonry, metal or factory-built flue shall not be used
to supply combustion air to the boiler. A separate
combustion air intake pipe routed back to the boiler can
be used in the remaining space if required, the boiler
venting system is approved for zero clearance, and can
be run directly beside the combustion air intake pipe.
32
Vitodens Rigid and Flex Venting Systems Installation
(continued)
WARNING
Different manufacturers offer a number of different
joint systems and adhesives. Do not mix pipes, fittings
and/or joining methods from different manufacturers.
Failure to comply could result in leakage, potentially
causing personal injury or death.
Do not install vent pipe in a way that flue gases flow
downwards. The direction of flue gas flow must be
vertically upwards or horizontal with an upward slope.
Ensure there is no flue gas leakage into the area in which
the boiler is installed.
Check joints for leaks with the gas supply turned off and
the fan running. Use a soapy solution to check for vent leaks.
Condensate must drain from the flue pipe to the boiler.
Ensure a suitable gradient of at least 3º [approx. 2 in. per
3.3 ft. (50 mm per 1 m)].
No condensate trap is required in the vent pipe system.
If exhaust vent pipe system passes through an unheated
space, such as an attic, it must be insulated. The
insulation must have an R value sufficient to prevent
freezing of the condensate. Armaflex insulation with b in.
thickness and higher can be used.