Weir SPM QWS 2500 XL, Operation Instruction And Service Manual, Page: 30 / 44

30 of 44
Document P/N: 2P137414
Release Date: 05/29/2017
Revision: IR
Power End Lube System Operating Specifications
Power end lube system readings will vary considerably due to the viscosity changes in the gear oil as it warms
and thins from a cold startup until it reaches full operating temperature. The system pressure and vacuum
variations are caused by the viscosity changes in the oil. The typical ISO gear oil even at room temperature is
very viscous, creates much resistance to flow in the system, and creates high system pressures even at very
low lube flow rates. Likewise, the typical ISO gear oil at 150F to 175F becomes much less viscous, flows more
freely, and creates much less resistance in the system showing up as lower system pressures.
Due to the extreme viscosity changes in the gear oil and due to the many different possible system designs, it is
difficult to establish a firm set of system readings which will be highly accurate for every system. Each system
will vary somewhat especially in the area of stabilized temperature and pressure readings during full
horsepower or full torque plunger pump operation. The system specifications herein should be observed in
addition to each unit’s “normal” system characteristics after having been put into service. Deviations from
“normal” in any unit’s system is an important factor in spotting potential problems and avoiding power end
damage due to insufficient lubrication.

Maximum Acceptable Vacuum Reading at Lube Pump Suction Inlet:
10inHg (Any Time While Operating the SPM
®
Plunger Pump)

Maximum Oil Pressure at Cold Startup and Full Engine RPM:
175 PSI

Maximum Oil Temperature:
175F (With General Service ISO 220 Gear Oils)
130F (With Cold Weather ISO 150 Gear Oils)
195F (With Hot Weather ISO 220 Gear Oils)

Approximate Normal Oil Pressure:
70-100psi (At Stabilized Operating Temperature and Full Engine RPM)

Minimum Oil Pressure:
50 PSI (At Any Time While Operating the SPM
®
Plunger Pump at Full Engine RPM and at Stabilized
Operating Temperature)
NOTE : ANY SUDDEN VACUUM, PRESSURE, OR TEMPERATURE DEVIATIONS FROM NORMAL
(ESPECIALLY IF ACCOMPANIED BY ANY UNUSUAL NOISE, VIBRATION, OR SMOKE) INDICATE THE
NEED TO CEASE PUMPING OPERATIONS, AND INVESTIGATE THE PROBLEMS BEFORE POWER END
DAMAGE OCCURS. (SEE TROUBLE SHOOTING SECTION OF THIS MANUAL).