CENTRIFUGAL PUMP (BACKWASH PUMP) REPAIR - continued.
Seal assembly can be replaced with pump installed on frame.
Mark position of long screws on adapter to facilitate installation.
Remove four long and four short screws (1).
Tap pump case (2) with a soft rubber mallet to break it loose from adapter (17) and remove case.
Remove pump case gasket (3).
Because of tight fit of wear ring in housing,
wear ring must be removed in pieces. Be
sure to centerpunch drill point to ensure that
drill does not bite into casing.
If wear ring is to be replaced (see
inspection criteria), center punch wear ring
(4) exactly at midpoint between inner and
Position pump case (2) on drill press and
drill two 3/16-inch (4.76 mm) holes in wear
ring (4) to a depth of 3/4 in (19.05mm).
Pry wear ring (4) out of case (2) in pieces.
Lay pump impeller (7) on a block of wood
as illustrated and, applying downward
pressure to keep impeller from moving,
unscrew retaining screw (5). Remove
retaining screw, seal washer (6) impeller
(7) and key (8).
Pry off washer (9) and remove spring (10),
sleeve (11) and carbon disk (12).
To remove cover (13), it may be necessary
to pry it loose from adapter (17) using
recesses of bolts (16) as prying points.
With pump in horizontal position, tap cover
(13) lightly with a rubber mallet and
remove it; if necessary pry it loose with a
prying tool (i.e. flat tip screwdriver).