Ductwork Preparation; Ducting Recommendations - Thermador PROFESSIONAL VCIN JP Serie Manual De Instalación

Ductwork Preparation

Ducting Recommendations

Proper performance is dependent upon proper ducting.
Local building codes may require the use of make-up air
systems when using ducted ventilation systems greater
than speci ed cubic feet per minute (CFM) of air
movement. The speci ed CFM varies from locale to locale.
It is the responsibility of the owner and the installer to
determine if additional requirements and/or standards
apply to specific installations.
DO NOT USE FLEXIBLE DUCT; it creates back pressure/
air turbulence and reduces performance. Always use metal
ductwork with a minimum diameter of 6" (150 mm).
Always install a metal vent cover where the ductwork exits
the house.
COLD WEATHER installations should have an additional
backdraft damper installed to minimize backward cold air
flow and a nonmetallic thermal break to minimize
conduction of outside temperatures as part of the ductwork.
The damper should be on the cold air side of the thermal
break. The break should be as close as possible to where
the ducting enters the heated portion of the house.
MAKE-UP AIR: Local building codes may require the use
of make-up air systems when using ducted ventilation
systems greater than specified CFM of air movement. The
specified CFM varies from locale to locale. It is the
responsibility of the owner and the installer to determine if
additional requirements and/or standards apply to specific
installations.
For safety reasons, ducting should vent directly outdoors
(not into an attic, underneath the house, into the garage or
into any enclosed space). The unit cannot be used in
conjunction with a recirculation unit.
If using a 10" (254 mm) duct, THERMADOR
not exceeding 150 ft (46 m) of duct.
Keep duct runs as short and straight as possible. Elbows
and transitions fittings reduce air flow efficiency. Back to
back elbows and "S" turns give very poor delivery and are
not recommended.
A short straight length of duct at the inlet of a remote
blower gives the best delivery.
Hoods are supplied with a 10" (254 mm) round transition. A
locally supplied transition is required for other sizes.
Transitions, elbows and wall or roof caps are all factors that
will add more static pressure, therefore increasing your
equivalent duct run. For example, assume you have 30 ft
(9.2 m) of straight 10" (254 mm) duct with two 90° elbows
and an outside wall cap. To calculate the equivalent
straight duct run pressure, you would add 12 ft (12.7 m) for
each elbow, and 5 ft (1.5 m) for the outside wall cap,
increasing your equivalent total run from 30 to 59 ft (9.1 to
17.9 m).
Use Table 4 on page 8 to compute permissible lengths for
duct runs to outdoors.
NOTE:
Do not exceed maximum permissible equivalent lengths.
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