Sullair ShopTek ST7 - 6.12 Troubleshooting Guide

ShopTek™ ST4, ST5, ST7, ST11, ST15 Three-phase 60 Hz User Manual 6: Maintenance
88292018-236 R00
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6.12 Troubleshooting
The information in the Troubleshooting Guide describes
symptoms and usual causes for the listed discrepancies.
However, do not assume that these are the only mal-
functions or fault conditions that may occur.
NOTE
For additional troubleshooting guidelines, con-
sult the controller’s User Manual.
Table 6-3: 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 - if fault persists, check motor
contacts for proper function.
Low incoming line voltage
Check voltage - in the case of low volt-
age, check power source, or contact
local power company.
Compressor shuts down
under service load condi-
tions
Loss of control voltage Check 110V AC power supply.
Low incoming line voltage
Check voltage - in the case of low volt-
age, check power source, or contact
local power company.
High operating pressure
Reset - if fault persists, check line pres-
sure and ensure that it does not exceed
the compressor’s maximum operating
pressure.
Compressor shuts down
under service load condi-
tions - High Pressure Fault
Compressor pressure setting incor-
rect
Change setting in Controller.
Control line strainer clogged Clean or replace strainer.
Minimum pressure valve malfunc-
tion
Repair or replace minimum pressure
valve.
Control line air leak Repair leak
Defective unload solenoid valve
Check valve – if it does not operate
when energized, replace the valve coil
or the entire valve if defective.
Compressor shuts down
under service load condi-
tions - High Temperature
Fault
Cooling air flow restricted
Clean cooler and check for proper ven-
tilation.
Ambient temperature too high
Check ventilation and increase if too
low.
Low fluid level Add fluid.
Clogged fluid filter Change the fluid filter element.
Thermal valve malfunction Replace thermal valve element.
Temperature sensor RTD malfunc-
tion
Check connection and sensor –
replace if sensor is defective.
Cooling fan rotational direction is
reversed.
Reconnect fan motor cables for proper
rotational direction.