Miele PWT 6089 Vario, Инструкции по эксплуатации и монтажу, Страница: 88 / 96

To calculate the total duct
length
Friction against the inner walls of the
vent ducting will slow down the
expelled air as it passes through the
ducting. An elbow, bend, non-return
flap or wall vent creates more friction
than a straight duct. The friction
created by each of these is expressed
as an
additional duct length factor .
The additional duct length factors are
calculated by comparing the friction
created by, for example, an elbow to
that created by 3' 3" (1 m) of straight
plastic piping (see Table 1).
The additional duct length factor for
each item needs to be added together
to ascertain the
total length which will
be needed for the venting system. The
total duct length is a means of
calculating the friction created by the
venting system as a whole.
A larger internal duct diameter also
helps reduce friction. If the total duct
length is
more than 65' (20 m) , the
duct diameter should be increased
(see Table II).
Procedure
1. First measure the distance requiring
straight ducting. Multiply this amount
by the corresponding additional
length factor in
Table I .
2. Establish the number of angles,
bends etc., and add their additional
length factors together with the help
of
Table I .
3. Add all the additional length factors
to give the total duct length.
4. Refer to Table II for the appropriate
duct diameter required.
Table I
Component Additional duct
length factor
Flexible ducting*
–
3' 3" (1 m) straight
–
45° angle
Bend radius =
9 3/4" (0.25 m)
–
90° angle
Bend radius =
9 3/4" (0.25 m)
6' (1.8 m)
5' (1.5 m)
8' (2.5 m)
Flexible aluminium
ducting*/plastic piping
–
3' 3" (1 m) straight, or
3' 3" (1 m) straight pipe
–
45° angle
Bend radius =
9 3/4" (0.25 m)
–
90° angle
(Bend radius =
9 3/4" (0.25 m)
3' (1 m)
2' (0.6 m)
3' (0.8 m)
Wall vent kit* or window
vent kit*
–
with louvred grill
–
with non-return flap
(hinged flap)
3.8 m)
5' (1.5 m)
Non-return flap*
(see "Venting more than one
dryer via the same venting
system")
47' (14.3 m)
* optional accessory
Table II
Maximum total
duct length allowable
Internal duct
diameter required
66' (20 m)
132' (40 m)
262' (80 m)
4" (100 mm)
5" (125 mm)
6" (150 mm)
Installation - extraction ducting
88