SN55, SN55S, SN55V, SN75, SN75S, SN75V User Manual
6: Maintenance
02250247-571 R04
Subject to EAR, ECCN EAR99 and related export control restrictions.
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Line pressure rises
above unload pressure
set-point
Leak in control system caus-
ing loss of pressure signals
Check for leaks.
Inlet valve stuck open
Remove the intake hose and check for inlet
valve operation.
Defective unload solenoid
valve
Check that the valve is open when de-ener-
gized. Replace if necessary.
Plugged control line strainer
Clean strainer (screen and O-ring replacement
kit available).
Defective blowdown valve
Check that separator/sump tank pressure is
exhausted to the atmosphere when the sole-
noid valve opens. Repair or replace if neces-
sary (kit available).
Excessive compres-
sor fluid consumption
Clogged return line or orifice
Clean strainer (screen and O-ring replacement
kit available).
Clean orifice.
Separator element damaged or
not functioning properly
Change separator.
Leak in the lubrication system
Check all pipes, connections and components.
Excess fluid foaming
Drain and change.
Fluid level too high
Drain and change. Check that the compressor
temperature has not dropped below 170°F
(76.7°C).
Pressure relief valve
opens repeatedly
Defective pressure relief valve
Replace.
Plugged separator
Check separator differential.
Liquid water in com-
pressed air lines
Plugged strainer in moisture
drain line
Clean and service strainer located in the line off
the bottom of the water separator.
Water vapor condensation
from cooling and compression
occurs naturally
Remove the water vapor from compressed air
prior to distribution through the air system.
Check operation of aftercooler and moisture
separator. Install a compressed air dryer sized
for the flow and dryness level required. (Note:
Filters may also be required to remove particu-
lates, liquid oil aerosols or for oil vapor removal.
Change cartridges as recommended by the fil-
ter manufacturer). Check all drain traps rou-
tinely to insure their proper operation. Maintain
them regularly.
Defective drain solenoid valve
Ensure valve opens and closes as signaled by
the STS Controller™.
Inadequate drain timer settings
Check STS Controller control drain interval and
drain time, and adjust accordingly. High humid-
ity conditions require longer drain times or more
frequent openings.
Symptom
Probable cause
Remedy
