SHD-138 Manual
17
Troubleshooting
If symptoms of poor performance develop, the following chart can be used as a guide to investigate
and correct the problem. When diagnosing faults in operations of the air compressor, always check
that the hydraulic power source is supplying the correct hydraulic flow and pressure that is listed in
the compressor specification section of this manual.
Problem
Compressor will not start:
Compressor runs slow or
slows down during
operation:
Compressor will lock up
after operating for a short
period:
Compressor runs hot:
Possible Cause
PTO not engaged.
Emergency brake off.
Blown fuse.
Loose or broken power/ground wire.
Compressor manifold solenoid will not
engage.
Loose air lines or hoses.
Hydraulic flow too low.
Hydraulic motor worn.
Hydraulic relief set too low.
Faulty compressor valves.
Pilot valve leaking air.
Centrifugal unloader valve leaking.
Hydraulic oil temp high.
Hydraulic motor drive coupler loose.
Faulty hydraulic relief valve.
Faulty check valve.
Dirty after cooler or intercooler tubing.
Faulty compressor values.
Dirty intake muffler.
Low crankcase oil level.
Solution
Engage PTO.
Fully engage parking brake.
Replace fuse.
Repair connection.
Repair wiring to coil.
Replace valve.
Tighten air lines and hose connections.
Check and reset flow.
Replace with new motor.
Readjust relief valve.
Clean or replace.
Replace pilot valve.
Remove the governor release valve cap, giving
access to the unloader pressure release valve
spring and ball - Clean thoroughly and
reassembly.
Hydraulic fluid low.
Hydraulic reservoir size incorrect.
Reposition and tighten coupler.
Remove relief valve, inspect o-rings and backup
seals or replace relief valve.
Clean or replace check valve.
Remove and clean.
Clean or replace valves.
Clean or replace.
Add compressor oil as needed.