
SHD-138 Manual
18
Problem
Compressor will not shut
down:
Compressor continues to
build air during idle mode:
Compressor will not speed
up when compressor is
activated:
Engine RPM will not
increase when compressor
is activated:
Compressor cycles or runs
often:
Chassis engine RPM
continue to operate at high
speed when air receiver
reaches maximum capacity:
Possible Cause
Air line or air hose leaks.
Misadjustment of pilot valve.
Pilot valve leaking air
Centrifugal unloader valve is leaking.
Moisture or rust contamination.
Faulty low pressure intake valve.
Leaking or misadjustment of the pilot
valve.
Air reservoir full.
Faulty pressure switch.
No 12 volt power to coil solenoid
valve located on hydraulic manifold.
Loose wiring.
Faulty pressure switch.
Faulty speed control.
Faulty pressure switch.
Excessive water in air reservoir.
Pip lines leaking air.
Misadjustment of pilot valve.
Air leaking from pilot valve.
Check valve leaking.
Faulty pressure switch.
Pressure switch wiring.
Solution
Tighten air lines or hose connections.
Adjust valve per manual specifications.
Clean or replace pilot valve.
See “Compressor runs slowly” section.
Remove filter bowl. Fill with WD40 lubricant.
Open air tank valve. Run compressor for 10
minutes. Partially close air tank valve and cycle
compressor. Repeat as needed.
Clean or replace low pressure intake valves.
Tighten or adjust valve per manual specs.
Drain air from reservoir.
Test for 12 volt power on both the “C” and “NC”
side of the terminals. If no power on “NC” side
of pressure switch, replace switch.
Check fuse. Check ground wires. Check
chassis emergency brake switch.
Check wiring to : Solenoid valve, pressure
switch, ground wiring.
Replace pressure switch.
Check speed control wiring for loose or broken
connections. Check relay (For ECM operated
speed settings.)
Replace pressure switch.
Drain air reservoir.
Tighten or replace lines.
Adjust valve per manual specifications.
Clean, adjust, or replace.
Clean or replace.
Replace pressure switch.
Wires place on pressure switch incorrectly or
loose ground wire.
Содержание SHD-138
Страница 14: ...SHD 138 Manual 13 R40 Breakdown Assembly...