SECTION 6
®SULLAIR®
38
3700 Operator’s Manual and Parts List
6.10 TROUBLESHOOTING GUIDE
SYMPTOM PROBABLE CAUSE REMEDY
COMPRESSOR WILL NOT START Main Disconnect Switch Open Close switch.
Line Fuse Blown Replace fuse.
Motor Starter Overload Tripped Reset. Should trouble persist, check 
whether motor starter contacts are 
functioning properly.
Low Incoming Line Voltage Check voltage. Should voltage check low, 
consult power company.
COMPRESSOR SHUTS DOWN WITH 
AIR DEMAND PRESENT
Loss of Control Voltage Reset. If trouble persists, check that line 
pressure does not exceed maximum 
operating pressure of the compressor 
(specified on nameplate).
Low Incoming Voltage Consult power company.
Excessive Operating Pressure Separator requires maintenance; check 
maintenance indicator under full load 
conditions.
High pressure setting in microprocessor 
set wrong; reset.
Defective valve; regulator valve should 
cause inlet valve to close when the 
pressure switch contacts open. Repair if 
defective.
Defective blowdown valve; blowdown 
valve should exhaust sump pressure to 
25 psig (1.7 bar) when maximum 
operating pressure is reached. Repair if 
defective.
Discharge Temperature Switch Open Cooling water temperature too high; 
increase water flow (water-cooled only).
Cooling water flow insufficient; check 
water lines and 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.
Thermal valve not functioning properly; 
replace element.
Water flow regulating valve not functioning 
properly; change (water-cooled only).
(Continued)