Miele PDR 910 EL Plan D'installation page 7

This will help to stop a reduced dryer performance and excessive time and energy re-
quirements.
Use:
- for the vent ducting: exhaust air hose* or a plastic waste water pipe (e.g., HT piping sys-
tems) with a minimum diameter of 4" (100 mm). Observe local codes.
- for the extraction ducting outside: wall pipe* or window connection*. Observe local
codes.
*optional accessories
Calculating the total ducting length
The friction of the vent ducting with its bends and various components provides resistance
to the flow of exhaust 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 compared to 1 meter 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).
Procedure
1. Measure the length needed for the straight sections of vent 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 to calculate the total
ducting length.
4. Refer to Table II for the pipe diameter needed for the total ducting length.
Table I
Components
Exhaust air hose (flexible aluminum)* / pipe (temperature resistance
min. 175°F (80°C))
– 3' 3" (1 m) laid straight or 3' 3" (1 m) straight pipe
– 45° bend (radius of bend = 10"(0.25 m))
– 90° bend (radius of bend = 10" (0.25 m))
The use of a wall pipe or window connection is regarded as an exception to the design principles of the
exhaust air management system. This must be carried out in accordance with the applicable local
building regulations. Seek approval from the relevant building inspector where necessary.
Wall pipe* or window connection*
– with inserted grate
– with non-return flap (swinging flap)
Non-return flap*
* optional accessories
en - Installation notes
Relative pipe length
3' 3" (1.0 m)
2' (0.6 m)
2' 7 1/2" (0.8 m)
12' 5 5/8" (3.8 m)
4' 11" (1.5 m)
46' 11" (14.3 m)
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