Pentair Hydromatic SPD50H Manuel D'utilisation page 7

MAINTENANCE & REPAIR
SEAL HOUSING
The pump is equipped with two mechanical seals mounted in
tandem. The lower seal (#14) and the upper seal (#5) consist of a
ceramic stationary seat and a carbon rotating ring.
As noted, if water is detected in the motor housing, inspect the
power cord connection, pipe plug connections, O-rings, the
motor housing itself, and the two mechanical seals.
There are two quarts of oil in the motor housing. This is a
paraffinic SE-40 process oil. The same oil is used in the seal
housing (#20) between the two mechanical seals. To check the
seals, remove the lower housing pipe plug (#8) and pour the oil
out into a clean, preferably glass, container. Look for the milky
color as noted previously.
If the oil is clear, the lower seal is still good. If this seal is
damaged, water will seep in and continue to stain the oil,
changing it from clear, to slightly discolored, to cloudy, and
finally to a milky white.
Except for very rare instances, the motor will continue to be
protected by the upper mechanical seal.
LOWER SEAL
If water is found in the seal chamber, the lower seal must be
replaced. Separate the volute by removing the three cap screws
(#9) holding the base (#12) to the upper volute.
Insert a large screwdriver in the slotted pump shaft and strike
the impeller sharply with a plastic or rubber headed hammer.
The impeller should spin free. The impeller holds the rotation
carbo ring of the lower mechanical seal against the stationary
ceramic seat by compressing a stainless steel spring.
When the impeller is removed, the spring will relax, allowing the
carbon ring to be removed. There is a rubber sleeve (bellows)
inside the spring which grips the pump shaft. This often
restricts the spring and must be pried or pulled loose.
With the carbon ring, spring, and rubber sleeve removed, wedge
the ceramic seat out of the housing. Be sure not to scratch or
mar the pump shaft.
UPPER SEAL
1. To remove and replace the upper mechanical seal (#5), the
base (#12), impeller (#11), lower mechanical seal (#14), and
volute (#7) must be removed first. Drain the seal oil from
the housing by removing pipe plug (#8).
2. The rotating carbon ring and stainless steel spring are
held in place by a snap ring (#27) and washer (#10). Remove
these.
W-03-193 (10-15-22)
3. Remove the four hex head stator bolts and lift the stator
(#3). A screwdriver can be inserted under the stator shell in
order to remove the stator.
4. Bump the end of the shaft with a plastic hammer. This will
push the rotating half of the mechanical seal from the shaft
and also push the lower bearing from the seal plate. Now
remove the shaft, rotor, and bearing assembly from the
seal plate.
5. If water was found in the oil, the rotating and stationary
halves of the mechanical seal must be replaced. Remove
the stationary seal half by inserting a screwdriver into seal
plate from the top and tapping lightly with a hammer.
6. Turning the bearing by hand: if it feels rough when turned
or looks rusted, it should be replaced. Obtain a bearing
puller to remove the bearing. If a puller cannot be replaced
over the bearing, remove the outer face by cracking in a
vise. Now the outer face and balls can be removed, allowing
the inner face to be pulled.
REASSEMBLY
1. Thoroughly clean the seal plate (#20), particularly the seal
and bearing pockets. All sand and dirt must be removed.
2. If the stationary seal half was removed, use a plastic
pusher to press it into the housing. Make sure the rubber
ring goes in first. Do not use any sharp objects that may
damage the seal.
3. When installing a replacement bearing, press only on the
inner face and make sure the bearing is flush against the
snap ring. If a press is not available, the bearing can be
tapped onto the shaft using a sleeve that bears only on the
inner face. Pressing on the outer face will ruin the bearing.
4. Push the shaft, rotor and ball bearing assembly into the
seal plate, being careful not to chip the ceramic of the
stationary seal half.
5. Replace the stator if it is visibly burned or if the ground
resistance test or the winding resistance test has failed.
Note that the replacement stator must be of the same
manufacture as the existing rotor, or vice versa. Replace
the four stator bolts.
6. Remove the old O-ring (#19), regardless of condition, and
replace. Place the new O-ring over the seal plate shoulder.
Do not roll it. If twisted, water may enter chamber and
cause failure.
7. Clean the motor housing thoroughly, then position it onto
the seal plate.
8. Press the rotating seal half onto the shaft with the rubber
ring facing the impeller.
7