wc_tx000178gb.fm
29
PG 2A / 3A
Maintenance
5.4
Adjusting the Impeller Clearance
If it is necessary to replace impeller or volute, be sure clearance between impeller
and volute is adjusted correctly. The impeller
(a)
should be as close to the volute
(b)
as possible without rubbing against it. Clearance is adjusted by adding or
removing shims
(c)
from behind impeller. To adjust the clearance do the following:
1. Remove pump housing but do not remove impeller.
2. Measure the distance
(d)
of volute.
3. Measure the distance
(e)
of impeller.
4. Subtract the distance
(e)
from
(d)
.
5.
(d) - (e) = (f)
clearance.
6. The clearance between the volute and the impeller should be 0.3 mm (0.012 in.)
to 0.7 mm (0.028 in.). Adjust the distance by removing the impeller and adding
shims as needed.
Each shim measures 0.3 mm (0.012 in.).
As the impeller wears down, additional shims may be required to maintain the
clearance between the impeller and the volute. Check the clearance whenever the
mechanical seal
(g)
, impeller, volute, or rear flange plate are replaced.
b
d
e
g
c
a
f
wc_gr000838
