Miele PDW 909 Instrucciones De Instalación página 34

en - Installation notes
The following
should be avoided:
Use:
Calculating the
total ducting
length
Procedure
34
The air required for drying is taken from the room where the dryer is
installed. You must therefore ensure that the room is sufficiently vent-
ilated. Otherwise, there is a risk of suffocation due to exhaust gases
being sucked back from other technical systems or fuel-burning in-
stallations, and the drying time will be much longer.
- Long vent ducting
- Too many tight bends or elbows
This will help to stop a reduced dryer performance and excessive
time and energy requirements.
- For the vent ducting: exhaust hose* or a plastic waste water pipe
(e.g. HT piping systems) with a minimum diameter of 100 mm.
- *optional accessories
The friction of the vent ducting with its bends and various compon-
ents provides resistance to the flow of air. This friction resistance is
expressed as a relative pipe length. The relative pipe length indicates
how much greater the resistance of a bend is, for example, when com-
pared to 1 metre of a straight plastic waste water pipe (table I).
Adding together the relative pipe lengths for all of the components
gives the total ducting length. The total ducting length expresses the
resistance of the entire exhaust air system.
As a larger duct diameter has a lower flow resistance, a longer duct
requires a greater duct diameter (table II).
1. Measure the length needed for the straight sections of ducting.
Multiply this value by the corresponding relative pipe length from
table I.
2. Calculate the number of bends and components needed. Use
Table I to help you add together their relative pipe lengths.
3. Add together all of the relative pipe lengths calculated above in
order to calculate the total ducting length.
4. Refer to Table II for the pipe diameter needed for the total duct-
ing length.
Table I
Components
Exhaust air hose (flexible aluminium)* / pipe
(temperature resistance min. 80 °C)
– 1 m laid straight or 1 m straight pipe
– 45° bend (radius of bend = 0.25 m)
– 90° bend (radius of bend = 0.25 m)
Non-return flap*
* optional accessories
Relative pipe length
1.0 m
0.6 m
0.8 m
14.3 m