NPK GH1 - Troubleshooting; Troubleshooting Chart; Determining the Cause of the Problem

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TROUBLESHOOTING
UNDERSTAND THE BASICS:
1. The NPK HYDRAULIC HAMMER hydraulic operating pressure is determined by the
nitrogen gas pre-charge pressure in the hammer, not the relief valve setting of the
carrier. NPK Hydraulic Hammers are self-regulating for hydraulic pressure.
2. The NPK HYDRAULIC HAMMER energy per blow is determined by the nitrogen gas
pre-charge pressure, not the pump volume. Impact energy is proportional to gas
pressure.
3. The NPK HYDRAULIC HAMMER frequency (blows per minute) is determined by oil
flow to the hammer. Frequency is proportional to oil volume (gallons per minute or
liters per minute). The hammer circuit must be set to provide the correct flow to the
hammer.
TROUBLESHOOTING CHART
PROBLEM CAUSE CHECK REMEDY
Loss of impact power. Low gas pressure. Gas pressure Recharge gas.
Loss of frequency.
(hammer slows down)
Gas pressure too high. Gas pressure Reduce gas pressure.
Shut-off valve partially closed. Valve position Open valve.
Relief valve set too low (must be
400 to 500 psi over hammer
pressure).
HYD Pressure Adjust or replace.
Hyd. temperature too high (over
180°F).
Oil Temperature Reduce throttle, clean or add
oil cooler.
Hydraulic pump volume too low. Oil Flow Increase circuit flow.
Oil level of carrier too low. Oil Level Add hydraulic oil.
Erratic running or
stops running.
Defective pump or control valve. HYD Pressure Repair or replace.
Shut-off valve closed. HYD Pressure Open valve.
Hoses reversed. HYD Pressure Pressure is on left. Return is on
right.
Return line blocked. HYD Pressure Eliminate obstruction.
Oil level of carrier too low. Oil Level Add hydraulic oil.
Gas pressure too high. Gas Pressure Reduce gas pressure.
Zero gas pressure. Gas Pressure Check for leak and repair.
Hammer main valve malfunctioning. HYD Pressure Disassemble and inspect valve
components.
Piston not cycling. HYD Pressure Disassemble hammer and
inspect piston.
DETERMINE THE CAUSE OF THE PROBLEM
Technical problems are caused by either (1) the hydraulic hammer or (2) the hydraulic
system (carrier hydraulics or installation kit). Checking the hydraulic pressure and flow,
and the hammer gas pressure, will determine if the problem is in the hammer or the
carrier. If the pressures and flow available to the hammer are correct, the problem is in
the hammer.