Sullair ShopTek ST400 User Manual page 70

USER MANUAL
S T
™
HOP EK
Table 6-3: Troubleshooting Guide
SYMPTOM
Compressor cannot produce
full discharge pressure
Line pressure rises above
unload pressure set-point
High compressor fluid
consumption
Pressure relief valve opens
frequently
68
PROBABLE CAUSE
Air demand too high
Dirty air filter
Inlet valve bleed orifice
obstructed/plugged
Defective unload solenoid valve
Minimum pressure valve
malfunction
Pressure sensor malfunction
Belts slipping due to lack of
tension
Control system leak causing loss
of pressure signals
Inlet valve stuck open
Defective unload solenoid valve
Plugged/obstructed control line
strainer
Pressure sensor malfunction
Clogged return line or orifice
Separator element damaged or
malfunctioning
Lubrication system leak
Excess fluid foaming
Fluid level too high
Pressure relief valve defective
Plugged/obstructed separator
Pressure sensor malfunction
02250180-090 R00
REMEDY
Check service lines for leaks or open
valves.
Replace filter.
Check the control line bleed orifice inside
the inlet valve for blockage or obstructions.
Check the valve - if it does not operate
when energized, replace the valve coil or
the entire valve if defective.
Repair or replace minimum pressure valve
Check connection and sensor – replace if
sensor is defective.
Ckeck belts. Re-tension or replace as
necessary.
Check for leaks.
Remove the intake hose and check the inlet
valve for proper operation.
Check the valve for proper operation - open
when energized - replace if necessary
Clean or replace strainer
Check connection and sensor – replace if
sensor is defective.
Clean or replace the strainer.
Change separator.
Check all pipes, connections, and
components.
Drain fluid and change.
Drain and change - check that the
compressor temperature has not dropped
below 170ºF (76.7ºC).
Replace.
Check separator differential.
Check connection and sensor - replace if
sensor is defective.
SECTION 6