Model 30000-S DHPU Manual
Rev. 0
JRK
17SEP12
Page 24
Table 2: Troubleshooting the Power Unit Hydraulic Circuit
Problem
Solution
Power unit performance is
poor
1) If the flow rate seems low, then verify the operation
mode handle is in the correct position. When in tubing
mode, the flow is limited to a smaller volume.
2) If the flow rate seems low, then make sure the Hydro-
Throttle is shifting as required
3) Check the motor oil level to ensure it is not too high.
4) Inspect the engine air filter for debris. Clean or
replace if clogged.
5) Make sure the fuel filter is not clogged. Replace the
filter if blocked by debris, and vent the fuel system.
6) Inspect the fuel lines and fittings for leaks or entry
points for air to enter the system. Vent the fuel system
after addressing the problem.
7) Verify the engine inlet-outlet valve clearance is per the
engine manual's recommendation. Adjust if required.
8) Inspect and replace the fuel injector if it is defective.
9) Inspect the hydraulic system for an excessive pressure
drop, which could be caused by any of the following.
a) Verify the quick disconnects are completely
tightened and engaged.
b) Inspect the return filter pressure gauge. Replace
the filter elements if required.
c) Ensure the hoses are adequate for the power unit
flow (1" for pressure, 1-1/4" for return).
10) Verify the correct viscosity of fluid is utilized for the
operating temperature. Change fluids if necessary.
11) Check the hydraulic fluid temperature. If too hot,
then allow the unit to cool. Inspect the heat exchanger
fins, and clean if clogged with debris. Verify the fan
motor is spinning.
Power unit comes out of idle
position slowly
1) Inspect the Hydro-Throttle and replace or rebuild as
necessary.
2) If the ambient temperature is low, then warm up the
power unit to raise the hydraulic fluid temperature and
lower the viscosity.
3) Verify the correct viscosity of hydraulic fluid is used
for the operating temperature. Change fluids if necessary.
Hydraulic pump operation is
excessively noisy
1) Verify the correct viscosity of hydraulic fluid is being
utilized for the operating temperature. Change fluids if
necessary.
2) Ensure that air is not entering the suction lines of the
pump. Check for leaks in the line.
3) Inspect the fluid level of the hydraulic reservoir. If the
level is below the sight glass, then add hydraulic fluid.
4) Excessive noise, vibration and heat would be
