Troubleshooting Guide- Electro-Mechanical - Sullair LS-25 Operator's Manual And Parts List

7.7 TROUBLESHOOTING GUIDE- ELECTRO-MECHANICAL

SYMPTOM
COMPRESSOR WILL NOT START
COMPRESSOR SHUTS DOWN
WITH AIR DEMAND PRESENT
PROBABLE CAUSE
Main Disconnect Switch Open
Line Fuse Blown
Control Transformer Fuse Blown
Motor Starter Overload Tripped
Low Incoming Line Voltage
Loss of Control Voltage
Low Incoming Voltage
Excessive Operating Pressure
Discharge Temperature Switch Open
MAINTENANCE
REMEDY
Close switch.
Replace fuse.
Replace fuse.
Reset. Should trouble persist, check whether
motor starter contacts are functioning properly.
Check voltage. Should voltage check low, consult
power company.
Reset; if trouble persists, check that line pressure
does not exceed maximum operating pressure of
the compressor (specified on nameplate).
Consult power company.
Defect in pressure switch; check pressure at which
contact points open.
Separator requires maintenance; check mainte-
nance indicator under full load conditions.
Defective pilot valve; pilot valve should cause con-
trol lever to move to unload stop when the pres-
sure switch contacts open. Repair if defective.
Defective blowdown valve; blowdown valve should
exhaust sump pressure to 25 to 35 psig (1.7 to 2.4
bar) when maximum operating pressure is
reached. Repair if defective.
Cooling water temperature too high;
increase water flow (water-cooled only).
Cooling water flow insufficient; check water lines
valves (water-cooled only).
Cooler plugged; clean tubes. If plugging persists,
install water conditioner (water-cooled only).
Cooling air flow restricted; clean cooler and check
for proper ventilation.
Ambient temperature is too high; provide sufficient
ventilation.
Low fluid level; add fluid.
Clogged filter; change the fluid filter element and
change the bearing filter element if maintenance
indicator shows red.
Thermal valve not functioning properly; replace
element (air-cooled only).
Water flow regulating valve not functioning proper-
ly; change (water-cooled only).
Defective discharge temperature switch; check for
a short or open circuit to probe and correct wiring.
Low fluid pressure.
Low water pressure.
Section 7
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