16
PROBLEM
Elevated dew point
Optional Blue Moisture
Indicator (BMI)
indicates high
moisture level.
Excessive pressure
drop in dryer
Failure to shift
PROBABLE CAUSE
Insufficient purge rate.
Inlet air pressure below
design condition.
Flow rate higher than design
condition.
Inlet temperature above
design condition.(120°F)
Entrained water entering
desiccant bed.
Desiccant contaminated by oil
Elevated dew point
BMI wet
Excessive flowrate.
Inlet pressure below design
condition.
No input power.
Defective solenoid valve.
Solenoid valve seal failure
CORRECTIVE ACTION
Check purge flow settings.
Check purge piping for obstruction.
Clean purge piping and muffler.
Check pressure source and system
for leakage.
Check flowrate and cause for
increased demand. Correct flowrate
condition.
Check air compressor aftercooler,
clean and service as necessary.
Check air/moisture separator, prefilter
and drains. Replace dryer desiccant if
necessary.
Install suitable prefilter. Replace dryer
desiccant.
Refer to “Elevated Dew Point” correc-
tive actions above.
Depending on degree of saturation of
the desiccant, the BMI may take a
week or more of continuous use to
switch back to its blue (dry) state.
Check flow rate and cause for
increased air demand.
Check pressure source.
Check power input.
Check solenoid valve.
Inspect and replace seals as required.
9. TROUBLESHOOTING
Refer to maintenance descriptions in Section 8 as required for trouble shooting
procedures.
