•
Remove and clean the backwater preventer <25>. To do do, unscrew screws <1> and <2>
and push out the backwater preventer <25> from the side
27
23
30
•
fit the backwater preventer <25> again. Make sure that the
ventilation device <25A> is in a vertical position as shown
•
Close the cover of the service opening <30>
•
Carry out a functional check (see 3.7.2)
Maintenance
2
1
29
Ill. [21]
54 / 180
25
Ill. [22]
25
25A
2017/11