S 4Xx; Suction Power; Figure 4-2: S 4Xx Dustbag Change Indicator; Figure 4-3: Suction Power Curve - Miele S 247i Technical Manual

Technical Information
4.2.3

S 4xx

Figure 4-2: S 4xx Dustbag Change Indicator

Depending on the dust quantity and type, and the hose attachment in use, the
indicator shows when the dustbag should be changed.
If flour or fine mineral dust is vacuumed, the indicator may show that the
dustbag should be changed even if it is not full.
As the bag is filled, its permeability is reduced and the negative pressure level
in the bag is reduced. At the same time the negative pressure in the dust
compartment rises.
This increased negative pressure evacuates the dustbag change indicator
through its opening (Figure 4-2, Item 3) and removes air from the concertina
hose (Figure 4-2, Item 2). This then collapses and the visible indicator (Figure
4-2, Item 1) advances along its scale.
4.3

Suction Power

Figure 4-3: Suction Power Curve

The suction power is the product of the negative pressure developed and the
air throughput achieved divided by 10. The fan motor extracts air from the
S 2xx, S 3xx & S 4xx Canister Vacuums
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