Two factors must be used to determine the maximum length of hydraulic hose you can run from the hydraulic power unit to the submersible pump.
On the pressure side friction losses in the hose and couplings will reduce the amount of pressure available to the hydraulic motor. This will cause a reduction in power from the motor and may have an effect on the submersible pump output.
On the return side friction losses not only will effect performance but also create excess backpressure that can damage the hydraulic motor and possibly cause seal failure in the motor.
As a rule of thumb we recommend going to a larger return hose on running distances greater than 150ft (45m). Use a larger hose on the pressure side on distance over 150 ft (45m).
Case drain lines (third lines) are used to relieve any excess pressure build-up in the hydraulic motor casing on the submersible pump. The larger the hydraulic flow capacity of the system, the greater the need for case drain lines. All of Hydra-Tech’s power units 25HP (15GPM) and above have provisions for case drain lines to be fitted. All of Hydra-Tech’s pumps that operate with input flows over 35 GPM (132LPM) have case drain lines fitted as standard. Pumps that operate with flows from 15 to 35 GPM only require case drain lines when you are using 150 ft. (45m) or more hydraulic hose from the power unit to the pump. Units under 15 GPM (57LPM) normally do not require case drain lines and in applications over 150 ft from the power unit to the pump, a larger size return line can be used to reduce back pressure.