ZEKS Eclipse
TM
90-5,000ZPB Desiccant Dryers
www.zeks.com
25
10.0 TROUBLESHOOTING
PROBLEM
Elevated Dew-point
Blue Moisture Indicator (BMI)
Turns Gray
Excessive Pressure in Tower
Designated For Regeneration
(Above 3 PSI)
Inability to Maintain Line
Pressure On Drying Tower
PROBABLE CAUSE
Insu
ffi
cient purge
fl
ow
Improper valve operation
Inlet air pressure below design condition.
Flow rate is higher than design condition
Inlet temperature to the dryer exceeds the
rated capacity of the dryer.
Desiccant bed is
fl
ooded with moisture. The
BMI will turn gray when this occurs.
Indicator is saturated as a result of an
elevated dew point.
Purge Mu
ffl
er is clogged.
Air leak across Purge Mu
ffl
er.
Leaking Check Valve.
CORRECTIVE ACTION
• Check purge
fl
ow settings. Verify that purge
gauge is reading proper value.
• Inspect purge valve & control air solenoid valves
for proper operation.
• Inspect mu
ffl
ers for clogging.
• Verify operation of main
fl
ow and purge valves.
• Inspect control air solenoid valves for proper
operation.
• Verify check valves are maintaining desired
pressures by using jog and valve test functions.
Refer to valve test section.
• Check pressure source and inspect piping
system for leakages.
• Verify that the dryer was sized appropriately for
the operating conditions.
• Verify that compressor sizing is properly
matched to dryer capacity.
• For specialty systems where the outlet of the
dryer is piped to a booster compressor, verify
that the
fl
ow of the booster compressor is below
the rated capacity of the dryer. Excessive
fl
ow
will
fl
uidize desiccant bed and result in dusting
that will signi
fi
cantly reduce performance.
• Inspect the air compressor after-cooler and
drain to ensure proper operation. After-cooler
may require cleaning in to operate properly.
• Verify the inlet temperature does not exceed
120
o
F under normal operating conditions.
For applications that approach 120
o
F on
a continuous basis, dryer sizing should be
reviewed prior to operation of the dryer. The
standard design is rated based on an inlet
condition of 100
o
F @ 100 PSI and will not
deliver proper performance if it is undersized.
• Verify that the air compressor after-cooler drain
and the pre-
fi
lter drain are functioning properly.
• The desiccant will become saturated if
compressed air is permitted to
fl
ow through the
dryer before it is operating.
• If this occurs, the performance of the dryer will
not easily recover and this will void the warranty
on the desiccant material.
Refer to elevated dew-point corrective actions
listed above.
Inspect purge mu
ffl
ers for clogging and replace
as required. Follow proper safety precautions
during this process.
Determine if Inlet Valves and Outlet Check Valves
are functioning properly. Refer to valve test
section.
Utilize valve test function to determine if inlet and
outlet valves are functioning properly (NEMA 4
models only).
For Troubleshooting Procedures, refer to maintenance descriptions in SECTION 9 as required.