Denison Hydraulics P11S Series

Questions and Answers

J
John SandersAug 22, 2025
What to do if there are pressure shocks in my Denison Hydraulics P11S?
- T
  Tyler SolomonAug 22, 2025
  Pressure shocks in your Denison Hydraulics Water Pump can arise from several factors. These include a cogging load, which requires mechanical considerations, a worn relief valve or compensator, both needing repairs. Other causes are slow response in check valves (replace or relocate), servo pressure being too low to maintain firm control (increase pressure and check pressure drop through servo filter), excessive de-compression energy rates (improve decompression control), excessive line capacitance (reduce line size or lengths eliminate hose), or barrel blow-off (re-check pump hold-down, rotating group, drain pressure).
J
Jennifer HarrisSep 1, 2025
Why is there high wear in my Denison Hydraulics P11S Water Pump and motor?
- K
  Kevin BowmanSep 1, 2025
  High wear in your Denison Hydraulics Water Pump and motor can be caused by several factors: excessive loads (reduce pressure settings, reduce speeds), contaminant particles in the fluid (caused by improper filter maintenance, filters that are too coarse, introduction of dirt to the system, improper reservoir openings or breather, or improper line replacement), improper fluid (fluid too thin or thick for operating temperature, breakdown of fluid with time/temperature/shearing effects, incorrect additives in new fluid, or destruction of additive effectiveness with chemical aging), or unwanted water in the fluid (condensation, faulty breather/strainer, heat exchanger leakage, faulty clean-up practice, or water in makeup fluid).
E
ericabradleyNov 11, 2025
Why is my Denison Hydraulics Water Pump so noisy?
- M
  Michael LambNov 11, 2025
  A noisy Denison Hydraulics Water Pump can stem from several issues. It might be due to air in the fluid, caused by a leak in the suction line, low fluid level, turbulent fluid return lines above the fluid level, gas leak from the accumulator, excessive pressure drop in the inlet line from a pressurized reservoir or the suction line strainer acting as an air trap. Another cause might be cavitation in the rotating group because the fluid is too cold, too viscous, or too heavy; the shaft speed is too high; the suction line is too small or dirty; the operating altitude is too high; the boost or replenishment pressure is too low or the replenishment flow is too small for dynamic conditions. Misaligned shaft, faulty installation, distortion in mounting, axial interference, faulty coupling or exc...