TROUBLESHOOTING THE MAGNETIC STARTER
Check and replace fuse in main panel.
Fuse blown in main panel if
3-phase system
Motor wired for wrong voltage.*
Low voltage to motor
Check head unloader valve system.
Compressor starting under
pressure
Check wiring and reconnect as needed.
Power leads to motor
disconnected
Replace motor.
Motor burned out
See note.*
Voltage to coil too low to pull it in
Press “reset” on magnetic starter.
Overload tripped out
Reconnect or replace fuse.
Main power disconnected or
fuse blown
Check and free up or replace pressure switch.
Pressure switch contacts stuck
open
Replace starter assembly.
Defective starter
Inspect compressor valves and tank valves for carbon build-up.
Compressor overloading
causing motor overload
SOLUTION
POSSIBLE CAUSE
Motor hums but won’t
turn
Motor doesn’t hum
Magnetic starter coil
clicks
Coil chatters on & off
Coil does not click
Stops shortly after
starting or after running
a while
See note.*
Low voltage causing motor
overload
Stops shortly after running
Ventilate compressor room area or remove starter from
compressor and mount on wall.
Compressor or starter
overheating
Stops after running a while
PROBLEM
COMPRESSOR WON’T RUN
COMPRESSOR RUNS AND THEN STOPS
*NOTE: LOW VOLTAGE -
Low voltage can cause a multitude of problems. The most common cause of low voltage is when the wire size (gauge)
supplying power to the compressor is too small. The longer the run of wire the larger the diameter must be to overcome the inherent voltage loss
caused by the wire resistance. The supply voltage at the main panel could also be low as supplied by your local power company, or you may have
too many other pieces of equipment running off the same line. Your local electrician should be contacted to evaluate and correct the problem
according to the National Electrical Code.
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