Schreiber Chillers MC75AC - Manual (Page 12)

American Stainless Pumps
Stainless Steel Pumps for the Commercial Marketplace
www.aspumps.com 14032 S. Avalon Blvd. Los Angeles, CA 90061
Phone: (310) 630-8089 Fax: (310) 630-8095
Page 3
Operation Continued:
Check pump and motor for vibration. Vibration may be a sign of pipe strain, insufficient mounting or operation
beyond the pumps capacity.
The pump models SSP & SSPC are not designed for handling large amounts of solids. For the model SSP,
Spherical solids size should not exceed the vane height of the impeller, less 0.060”. For the model SSPC, solid
sizes must be smaller than the impeller vane family expressed in thousandths of an inch, less 0.140”.
Maintenance:
There is no scheduled maintenance required. Close-coupled pumps have no bearings. Bearings in the motors are
permanently grease lubricated and cannot be re-greased. Mechanical seals will need to be replaced when leaking.
O-Rings may harden with age and may need to be replaced when they leak.
Motor Bearings and Pump Thrust: Model SSP Only
Open impellers generate significantly more thrust than do enclosed impellers. The Model SSP with a 4.38” diameter
impeller operating at 20 psig generates about 150 pounds of thrust. This thrust load is carried by the motor bearing.
The standard jet pump motor and the standard SSP motor uses as a front and rear bearing a size 203 grease lubricated
bearing. This bearing has a B10 rated life of approximately 6,000 hours when operated with a thrust load of 150 pounds
at 3500 RPM. This rating means that 10% of all bearings operated in this condition will fail within 6,000 hours of opera-
tion. The average bearing life will be 3 to 4 times this 6,000 hours.
Pumps and motors which operate intermittently, or only operate 40 hours per week, will usually have acceptable bearing
lives with the standard jet pump motor bearing. Pumps that operate continuously, 24 hours per day, will have about 10%
of their thrust bearings fail in the first year of operation.
For service applications that are critical, for installations that are difficult to access, or for pumps operating at
differential pressures above 25 psig, American Stainless Pumps recommends that motors with a larger thrust
bearings and higher load ratings be used. Consult factory for pricing and details.
Disassembly:
Disconnect and lockout the electrical power before attempting any disassembly. Casing
may contain hazardous fluids. Drain and flush and take necessary precautions.
It is not necessary to remove piping from the case to disassemble. Pump is a back pullout design and unless casing
needs to be repaired or replaced, it can stay in place during servicing.
See page 7 for model SSP, and page 8 for model SSPC cross sectional drawings.
1. Close all valves and drain pump and pipes and flush if necessary.
2. Remove any motor hold down bolts.
3. Remove the eight (8) case bolts (Item 7CS) with a 3/16” allen wrench.
4. Pull the motor and pump internals back out of the case. The baseplate (Item 800) will slip off when the bottom
two case bolts are removed and can be left with the pump case. Remove the case o-ring (item 500) and
inspect for damage or hardness.
5. If the motor is a three phase motor, a locking mechanism (item 7SC) is used to prevent the impeller (item
200) from unthreading if started in the wrong direction. If motor horsepower is less than 1 HP, the starting
torque is relatively weak. ASP uses a locking compound to prevent the impeller from unthreading at start-
up. If the motor horsepower is equal to or greater than 1.0 HP, ASP will provide a left hand threaded, button
head locking screw with an impeller washer to prevent unthreading. The locking screw (item 7SC) is
installed with removable Loctite to prevent it from coming out when operating in the correct rotation. Remove
this locking screw by turning it clockwise while holding the impeller against rotation.
6. Remove the impeller (item 200) by turning the impeller counterclockwise (when looking at the impeller from
the pump end) while holding the motor shaft. It will be necessary to remove the motor shaft cover plate in the
center of the rear of the motor to get access to the shaft. Using a screwdriver, wrench or vise grips as
needed, hold the shaft tightly against rotation while turning the impeller. Do apply any heat to the
components. If you are unable to hold the shaft in this manner, remove the rear motor housing and grip the
motor shaft with vise grips or other similar device (do not hold shaft where bearings will mount).
7. Model SSP Only: There should be several spacing washers behind the impeller. These spacers locate the
open impeller vanes close to the case for efficient operation. Measure the thickness of this stack of spacers
for future reference. Remove them from the shaft but do not lose these washers. You will need them for
reassembly.