21
Troubleshooting
This section provides a list of the more frequently encountered compressor malfunctions, their causes and
corrective actions. Some corrective actions can be performed by the operator or maintenance personnel,
and others may require assistance of a Service Center. Contact NorthStar at 1-800-270-0810 for service locations.
PROBLEM
POSSIBLE CAUSE
Engine does not start.
A,B,C,D,E
Air delivery drops off.
H, I, J, L, M, N, P
Compressor does not come up to speed.
F, G, J, K
Compressor is slow to come up to speed.
F, G, J, K, L
Compressor will not unload cycle.
H, L, N, P
Compressor will not unload when stopped.
H, L, N, P
Excessive starting or stopping.
N, Q, S
Moisture in crankcase, “milky” substance in oil.
R
Oil in discharge air.
T
Safety/relief valve “pops”.
L, M, N
Low interstage pressure.
W
High interstage pressure.
V
POSSIBLE CAUSE
POSSIBLE SOLUTION
A.) Low Oil Shutdown
Fill engine with the adequate amount of oil.
B.) Cold Engine
Choke engine to start.
C.) No Fuel
Add gas to engine. Make sure fuel shutoff valve is open.
D.) Engine not turned ON
Place ON/OFF switch in the ON position.
E.) Spark plug wire not attached
Attach spark plug wire to spark plug.
F.) Compressor viscosity too high for ambient
temperature
Drain existing lubricant and refill with proper lubricant.
G.) Belt tension too tight or sheaves not aligned
Check tension/ alignment.
H.) Air leaks in discharge piping
Check tubing connections, Tighten joints or replace as
required.
I.) Compressor components leaky, broken, loose
Inspect components. Clean or replace as required.
J.) Loose flywheel or engine pulley, excessive end play in
engine shaft or loose drive belts
Check flywheel, engine pulley, crankshaft drive belt
tension/alignment. Replace or repair as required.
K.) Leaking check valve or check valve seat blown out
Replace check valve.
L.) Clogged or dirty inlet and/or discharge line
Clean or replace.
M.) Defective safety/relief valve
Replace.
N.) Unloader leaks or does not work
Realign stem or replace.
O.) Inadequate ventilation around flywheel
Relocate compressor for better air flow.
P.) Leaking, broken or worn inlet unloader parts at check
valve
Inspect parts and replace as required.
Q.) Excessive condensation in receiver tank
Drain receiver tank.
R.) Detergent lubricant in crankcase.
Replace with proper lubricant.
S.) Light duty cycle
Increase duty cycle.
T.) Lubricant level too high
Drain excess lubricant.
U.) Worn cylinder finish
Deglaze cylinder with 180 grit flex-hone.
V.) Low pressure inlet valve leaking
Inspect, clean or repair as required.
W.) High pressure inlet valve leaking
Inspect, clean or repair as required.
