Open shroud
Turn the screw (1)
N
counterclockwise until the shroud
can be swung upward
Pull the grip (2) in the direction of
N
the arrow to open the shroud
RE 521, RE 551 PLUS, RE 581, RE 581 PLUS
Add scale inhibitor
RE 551 and RE 581 only
Under normal operating conditions it is
not necessary to descale the machine if
STIHL scale inhibitor is used
consistently STIHL scale inhibitor is
specially designed for
STIHL detergents.
Mixing STIHL scale inhibitor with water
Measure the water hardness or
N
contact your water supply company
to establish the water hardness
range
Depending on water hardness – see
table:
Mix scale inhibitor at a ratio of A : B
N
with clean water – maximum
capacity of the storage tank = 1 l
A = scale inhibitor
–
B = water
–
RE 551
Unit water
Hardness
hardness
range
°dH
< = 12
> 12
°e
°f
ppm CaCO
mval/l
mmol/l
RE 581
Unit water
hardness
°dH
°e
°f
ppm CaCO
mval/l
mmol/l
Mixing ratio
(A : B)
1 : 2
undiluted
English
< = 15
1 : 2
> 15
undiluted
< = 21.4
1 : 2
> 21.4
undiluted
< = 214
1 : 2
3
> 214
undiluted
< = 4.28
1 : 2
> 4.28
undiluted
< = 2.14
1 : 2
> 2.14
undiluted
Hardness
Mixing ratio
range
< = 12
1 : 1
> 12
undiluted
< = 15
1 : 1
> 15
undiluted
< = 21.4
1 : 1
> 21.4
undiluted
< = 214
1 : 1
3
> 214
undiluted
< = 4.28
1 : 1
> 4.28
undiluted
< = 2.14
1 : 1
> 2.14
undiluted
43