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ECLIPSE™ DESICCANT DRYERS
ZPA HEATLESS MODELS
TABLE OF CONTENTS PAGE
1. INTRODUCTION 1
2. ABBREVIATED WARRANTY 1
3. HEATLESS DRYER NOMENCLATURE 2
4. RECEIVING AND INSPECTION 3
5. SAFETY AND OPERATION PRECAUTIONS 4
6. PRINCIPLES OF OPERATION 5
7. INSTALLATION / INITIAL START-UP 7
8. SCHEDULED MAINTENANCE 13
9. TROUBLESHOOTING 17
10. PURGE CHARTS 19
A
TTACHMENTS
A. GENERAL ARRANGEMENT DRAWING
B. WIRING DIAGRAM
C. FLOW DIAGRAM
D. SPARE PARTS LIST
E. ENGINEERING SPECIFICATIONS
ZEKS Compressed Air Solutions
1302 Goshen Parkway
West Chester, Pennsylvania 19380
610-692-9100 800-888-2323 FAX 610-692-9192
WWW.ZEKS.COM
COMPRESSED AIR SOLUTIONS
TM
ZPATM 90-5000 V0107
1
1. INTRODUCTION
ZEKS Eclipse™ Heatless Desiccant Dryers are designed to adsorb moisture from
compressed air. The dryers are constructed with two towers, each containing desiccant
beads, that alternate between online (drying) and offline (regenerating) modes, yielding a
continuous stream of dry air at the dryer’s outlet.
During normal operation, wet air passes through the on line tower and water vapor from
the air is adsorbed (collected) on the desiccant beads. While air is being adsorbed in the
online tower, the moisture on the desiccant in the offline tower is removed by a process
called desorption (regeneration). After an initial rapid depressurization, a portion of dried
air from the online tower passes over the desiccant bed and carries the moisture off the
bed and out the dryer’s exhaust.
The continuous, alternating process of adsorption and desorption is controlled using a
timer that switches the towers in a specific timed sequence. Very dry compressed air dew
points are achieved through the continuous switching and operation of this dryer. ZEKS
offers dryers to provide either -40°F, -80°F or -100°F pressure dew point outlet air.
2. ABBREVIA
TED WARRANTY
ZEKS Eclipse™ heatless desiccant dryer products are warranted to be free from defects
in material and workmanship for a period of 12 months from the original date of shipment
from the factory. To allow the warranty to be in effect for 12 months from the date of
equipment start-up, the Warranty Registration Card must be completed and returned to
ZEKS. Alternately, the Warranty Registration Card may be completed online at
www.zeks.com. The total warranty period cannot exceed 18 months from the original date
of shipment from the factory.
Equipment must be installed and operated in accordance with ZEKS’ recommendations.
ZEKS liability is limited to repair of, refund of purchase price paid for, or replacement in
kind at ZEKS’ sole option, during the warranty time period stated above. IN NO EVENT
SHALL ZEKS BE LIABLE OR RESPONSIBLE FOR INCIDENTAL OR CONSEQUENTIAL
DAMAGES, even if the possibility of such incidental or consequential damages has been
made known to ZEKS Compressed Air Solutions. In addition, the usual maintenance and
replacement type products are not covered by this warranty.
The warranties expressed above are in lieu of and exclusive of all other warranties. There
are no other warranties, expressed or implied, except as stated herein. There are no
implied warranties of merchantability or fitness for a particular purpose, which are specifically disclaimed.
Valves – After the Basic Warranty noted above expires the diaphragm valves on the ZPA
heatless dryers are warranted (parts only) for a total of 5 years from the date the dryer is
shipped from the ZEKS factory. The following applies to this warranty:
a. Check valves are excluded
b. Not applicable to dryers provided for -80 and -100 degree F dewpoint applications
c. Valves must be rebuilt every two years. Refer to Section 8. of this manual
d. Control line air filter element must be replaced once per year.
2
3. HEATLESS DRYER NOMENCLATURE
NOMINAL
FLOW
SCFM*
TYPE / DESIGN SERIES ELECTRICAL POWER OPTIONS
90 ZPA= Pressure Swing 1 = 115-1-60 (-40°F)
120
160
200
250
300
400 0= NEMA 1 0= STANDARD
500 H= NEMA 4 A= FAIL TO SHIFT
600 B= HIGH HUMIDITY
800 C= A + B
1000 M= MOISTURE LOAD
1200 CONTROL + A
1500 N= M + B
1800
2100
2700
3300
4000
5000
* Nominal Flows indicated are for 100°F inlet temperature, 100°F ambient temperature
and 100 psig compressed air pressure..
Nomenclature shown above represents standard price sheet options. Other options are
available, refer to nomenclature insert specific to your dryer for details.
NOTICE
3
4. RECEIVING AND INSPECTION
4.1 INSPECTION
Upon receiving your ZEKS air dryer, please inspect the unit closely. If rough
handling has been noticed, please note it on your delivery receipt, especially if the
dryer will not be immediately uncrated. Obtaining the delivery person’s signed
agreement to any noted damages will facilitate any insurance claims
4.2 UNPACKING AND HANDLING
Refer to labels on the dryer for the appropriate means for lifting or moving the
dryer. For those dryers that indicate lifting via the structural skid, forks should
extend all the way through the skid to reduce unnecessary forces to the dryer
during moving. When lifting the dryer, ensure that no stress is applied to the piping
or valving. Refer to Section 7.2 for locating and mounting of dryer.
NOTICE
Under no circumstances should any person attempt to lift heavy
objects without proper lifting equipment (i.e., crane, hoist, slings or fork
truck). Lifting any unit without proper lifting equipment, can cause
serious injury.
4
5. SAFETY AND OPERATION PRECAUTIONS
Because an air dryer is pressurized and contains mechanical parts, the same precautions
should be observed as with any piece of machinery of this type where carelessness in
operation or maintenance is hazardous to personnel. In addition to the many obvious
safety rules that should be followed with this type of machinery, the safety precautions as
listed below must be observed:
1. Only qualified personnel shall be permitted to adjust, perform
maintenance or repair this air dryer.
OSHA Heading
Description
2. Read all instructions completely before operating unit.
3. Pull main electrical disconnect switch and disconnect
any separate control lines, if used, before attempting to
work or perform maintenance on the unit.
4. Do not attempt to service any part while dryer is in an
operational mode.
5. Do not attempt to remove any parts without first relieving
the entire air system of pressure.
6. Do not operate the dryer at pressures in excess of its
rating.
7. Inspect unit daily to observe and correct any unsafe
operating conditions.
The user of any air dryer manufactured by ZEKS Compressed Air Solutions, is
hereby warned that failure to follow the above Safety and Operation Precautions
can result in personal injuries or equipment damage. However, ZEKS Compressed
Air Solutions does not state as fact, nor does it mean to imply, that the preceding
list of Safety and Operating Precautions is all inclusive, and further, that the
observance of this list will prevent all personal injuries or equipment damage.
NOTICE
“Warning” is used to indicate a
hazardous situation which has
some probability of death or
severe injury. Warning should
not be considered for property
damage accidents unless
personal injury risk is present.
NOTICE
“Notice” is used to indicate a
statement of company policy
as the message relates directly
or indirectly to the safety of
personnel or protection of
property. Notice should not be
associated directly with a
hazard or hazardous situation
and must not be used in place
of “Danger,” “Warning,” or
“Caution.”
CAUTION
“Caution” is used to indicate a
hazardous situation which may
result in minor or moderate
injury.
WARNING
5
6. PRINCIPLES OF OPERATION
6.1 INTRODUCTION
As described in Section 1, water vapor is removed from compressed air by diverting
air flow alternately between two towers filled with desiccant. While one tower
processes the compressed air stream, adsorbing water vapor, the opposite tower is
regenerated by desorbing the water vapor and venting it to atmosphere. Refer to the
Process and Instrumentation Diagram (P&ID) for a visual representation of the drying
and regenerating cycles.
6.2 DRYING CYCLE
Saturated compressed air enters the dryer and is diverted to the appropriate tower
by the Inlet Flow Valves. Referring to the Process and Instrumentation Diagram
(P&ID), the Left Inlet Flow Valve is actuated to a closed position to prevent air flow
from entering the regenerating tower. Simultaneously, the Right Inlet Flow Valve is
actuated to an open position, allowing air flow to the right hand tower. During this
time, the Right Tower Purge Valve is actuated to a closed position, preventing the
compressed air from venting to atmosphere. As the compressed air flows through
the desiccant material at pressure, removal of water vapor from the air stream begins
to occur through adsorption. In the adsorption process, the desiccant material draws
water vapor out of the compressed air and “holds” it until the right tower drying cycle
is complete. Compressed air flows out of the tower for delivery to the process use.
The Outlet Flow Check Valves provide air flow diversion to the outlet air connection
of the dryer. The Right Outlet Flow Check Valve allows air flow through to the outlet
connection of the dryer while The Left Outlet Flow Check Valve checks off to prevent
flow back to the regenerating tower.
6.3 REGENERATION CYCLE
Previously adsorbed moisture, removed from the process stream, gets stripped or
desorbed from the desiccant material in the regeneration process. The first stage of
regeneration is tower depressurization. After the Inlet Flow Valves are switched to
divert air flow away from the regenerating tower, the appropriate Purge Valve will be
opened and the tower will be depressurized. Through rapid depressurization, a
significant portion of the previously adsorbed water vapor is stripped off of the
desiccant material and exhausted to atmosphere.
The second stage of regeneration uses a portion of the dry, compressed air,
expanded to atmospheric pressure to complete the desorption process. As shown on
the P&ID, the compressed air exits the drying tower and a portion of the air flows
through the Purge Adjustment Valve and the Purge Orifice. Once the air has passed
through Purge Orifice, it expands to atmospheric pressure and continues the
regeneration process. Desorption occurs as the desiccant releases water vapor into
the regeneration air and is exhausted through the Purge Muffler.
Eclipse Heatless Dryers may be equipped with an optional Downstream Purge
feature. By adding additional check valves to the upper manifold, a dryer equipped
with the Downstream Purge option is able to use air from a downstream source to
purge the regenerating tower. This optional feature is useful for applications with
downstream (dry) storage tanks, as pulling air from a downstream source can
minimize cycling of the air compressor.
6
6.4 SETTING THE REGENERATION AIR FLOW
Proper setting of the purge is necessary to achieve proper dryer performance.
Setting the purge flow too high will waste compressed air and if set too low, the dryer
will not achieve proper dew point performance.
The purge adjustment manifold consists of the Purge Adjustment Valve, the Purge
Pressure Gauge and the Purge Orifice. When the right tower is the drying tower
(pressurized) and the left tower is depressurized (0 PSIG), manually adjust the
Purge Adjustment Valve until the gauge reading on the purge pressure gauge
matches the Purge Pressure Gauge setting listed on the laminated tag affixed to
the Orifice Plate Assembly.
6.5 TOWER REPRESSURIZATION
Upon completion of tower regeneration, and prior to the Inlet Flow Valves changing
position to switch towers, the regenerated tower must be repressurized.
Repressurization is accomplished by closing the appropriate Purge Valve. Closing
the Purge Valve allows the regeneration air to begin to pressurize the tower. In
addition to the regeneration air, the Repressurization Valve, (standard on -80°F and
-100°F dew point and high pressure dryers; optional on -40°F dew point dryers)
opens allowing some additional air from the outlet of the dryer to ensure adequate
pressurization. During normal tower regeneration, the Repressurization Valve is
held closed so that the only source of air for regeneration passes through the purge
adjustment assembly.
Failure to re-pressurize prior to tower switchover will result in shocking the
desiccant material and cause premature desiccant dusting.
NOTICE
The right tower must be the drying tower for proper purge adjustment setting.
When the left tower is the drying tower, the Purge Adjustment Gauge will read
close to line pressure.
NOTICE
On dryers equipped with the optional NEMA 4 / DPC™ Package or when using the
optional Moisture Load Control feature, the purge valve MUST be set to the factory
set point to insure proper operation of these features.
NOTICE
7
6.6 VALVES
Solenoid valves are used to actuate the Flow Valves, Purge Valves and the optional
Repressurization Valve on Eclipse Heatless Dryers. The Inlet Flow Valves and
optional Repressurization Valve are normally open valves, while the Purge Valves
are connected as nomrally closed valvaes. This arrangement permits air to flow
through the dryer during periods of loss of power.
Outlet Check Valves are single direction check valves that will allow flow in the
direction shown on the P&ID, but not allow flow in the opposite direction.
6.7 TIMING SEQUENCE
All timing functions on NEMA 1 dryers are performed by the Solid State Timer
(SST) and on NEMA 4 dryers by ZEKS DPC™ Controller. Regardless of controller,
the timing of ZEKS -40°F, -80°F and -100°F dryers is as follows:
6.7.1 TIMING CYCLE FOR -40°F DEW POINT DRYERS
The standard timing cycle for -40°F operation switches the Inlet Flow Valve
position every five minutes which alternates the drying tower. At the same
time as a tower Inlet Valve opens, the appropriate tower Purge Valve opens
to depressurize the regenerating tower. Tower regeneration occurs for 4
minutes and 15 seconds, at which time the Purge Valve closes to initiate
repressurization.
6.7.2 TIMING CYCLE FOR AND -80°F and -100°F DEW POINT DRYERS
The standard timing cycle switches for both -80°F and -100°F operation
switches the Inlet Flow Valve position every 2 minutes which alternates the
drying tower. At the same time as a tower Inlet Valve opens, the appropriate
tower Purge Valve opens to depressurize the regenerating tower. Tower
regeneration occurs for 1 minute and 50 seconds, at which time the Purge
Valve closes to initiate repressurization. The Repressurization Valve opens
to assist tower repressurization for the last 10 seconds prior to Inlet Flow
Valve switching.
7. ALARMS
AND INDICATORS
7.1 MOISTURE INDICATOR
The moisture indicator senses a sample of the control air supply which is taken
from the dryer outlet. The indicator provides an indication of dew point deterioration at the outlet of the dryer. Under normal operating conditions, the indicator is
blue. In the event of a dryer malfunction or prolonged dryer shut down, it will turn
gray in the presence of moisture.
7.2 FAILURE TO SHIFT ALARM (Optional)
The Failure to Shift Alarm provides an indication of switching failure in one of the
dryer switching valves. The Fail to Shift Alarm uses a pressure switch to monitor
the pressure in each tower.
8
At “0” PSIG the switches are normally closed which sends a signal to the controller.
When the towers pressurize, the switches open, thus removing the signal to the
controller. The controller anticipates the appropriate open and closed switch
position based on its timing sequence. If either switch is in an incorrect position,
the Failure to Shift Alarm light will illuminate on NEMA 1 dryers. Refer to the NEMA
4 / DPC™ Package Supplement for NEMA 4 dryers equipped with the DPC™
Controller.
7.3 HIGH HUMIDITY ALARM (Optional)
The purpose of the High Humidity Alarm is to provide the operator an indication if
the equipment fails to supply air at its designed dew point. This is accomplished by
passing a sample of dried air from the control line across a sensing element. If the
sensing element is exposed to air with dew point of -10°F or higher (for -40°F
dryers), the sensor sends a signal to the humidistat. On NEMA 1 dryers, power is
then supplied to the red alarm light on the enclosure. This light will remain on until
the problem is corrected and the sensing element has dried out. Refer to the
NEMA 4 / DPC™ Package Supplement for NEMA 4 dryers equipped with the
DPC™ Controller.
7.4 MOISTURE LOAD CONTROL (Optional)
The Moisture Load Control (MLC) feature is designed to minimize the loss of purge
air during low flow or low water loading conditions. On -40 °F units, a sensor
samples the moisture content from the online tower and provides a signal to a
humidistat. As long as the humidistat finds that the air in each tower is dry, it will
not allow the controller to open the Purge Valves. Once the moisture content in
either tower is found to reach the threshold point, the humidistat sends a signal to
the controller and initiates the regeneration cycle. For -80°F & -100°F dryers, a
digital dew point monitor is used in place of the humidistat. For dryers equipped
with the digital dew point monitor, refer to the Dew Point Monitor Addendum. For
NEMA 4 dryers equipped with ZEKS DPC™ Controller, refer to the NEMA 4 /
DPC™ Package Supplement.
9
7. INSTALLATION and START-UP
7.1 APPLICATION and CHECK ANALYSIS
To achieve the best dryer performance, you should carefully check that the design
and installation requirements outlined below are satisfied.
Operating pressure of ZEKS dryers can range from 75 -150 PSIG. Air available for
your usage will vary with operating pressure. The maximum design pressure of the
ZEKS Heatless Dryer is 150 PSIG. For units required for higher operating
pressures, consult your ZEKS representative.
The dryer must never be installed where air and/or ambient temperature exceeds
120°F or drops below +50°F. Locate dryer to avoid extremes of heat and cold from
ambient or other conditions. Avoid locating dryer outside or where it is exposed to
the elements.
7.2 LOCATING and MOUNTING
Lift the dryer only by the lifting points indicated by the lifting labels on the dryer.
Bolt the dryer to the foundation using the bolt holes provided in the base frame.
Anchor bolts should project a minimum of 3.5 inches above the foundation. Refer to
General Arrangement drawing for details.
7.3 PIPING
Pipe the compressed air lines to the inlet and outlet connections. Locate the
prefilters as close as possible to the dryer. Ensure the positioning allows for ease
of servicing. Refer to the General Arrangement drawing.
Note that the wet air inlet is at the dryer’s lower manifold, while the dry air outlet is
at the dryer’s upper manifold. In situations where air supply is required 24 hours a
day (it is undesirable to interrupt the airflow), a three valve by-pass system is
recommended to bypass the dryer. Use the fewest elbows necessary to keep
pressure drop at a minimum.
Once all piping has been connected, all joints including those on the dryer, should
be soap bubble tested at line pressure to ensure no joints have been damaged in
transit and site placement.
The standard dryer is not rated for any gas other than air.
NOTICE
ZEKS recommends that the mufflers be cleaned after initial start-up to remove
any desiccant dust generated during shipment. After running dryer for initial 30
minute period, de-energize / depressurize dryer and remove mufflers.
Disassemble and clean the removable insert inside the muffler core. Reinstall
mufflers prior to operating dryer.
NOTICE
10
7.4 FILTRATION
It is important that a prefilter and an afterfilter be provided in your dryer installation.
Coalescing prefilters, located before the dryer, protect desiccant beds from contamination by oil, entrained water, pipe scale, etc., thereby, extending dryer desiccant
life. Locate prefilters as close to dryer as possible.
It is recommended that a mechanical separator be installed immediately preceding
the prefilter to remove the bulk liquid and entrained water.
Particulate afterfilters, located after the dryer, help eliminate the possibility of
desiccant dusting and carryover into the air system.
7.5 ELECTRICAL CONNECTION
Make all electrical connections to the dryer as shown on the wiring diagram. Care
must be taken in connecting the proper voltages.
Size field connection knock-out for the conduit fitting required by the NEC.
7.6 DESICCANT LEVEL VERIFICATION
Remove desiccant fill port and the top of the desiccant vessel and check desiccant
level. The level should be consistent with the level depicted on the Desiccant Fill
Chart at the end of the manual
All dryers must have proper filtration. A .3 micron coalescing filter with
automatic drain & particulate after filter must be used as a minimum. Failure to
provide proper filtration for dryer will void warranty.
Dryer must be grounded with the full sized ground wire connected to an earth
ground.
Dryer must be fused according to NEC with the size fuse listed on the dryer
serial nameplate, or on specification sheet in technical manual.
NOTICE
NOTICE
NOTICE
11
7.7 START-UP
• Slowly pressurize the dryer. When the dryer reaches full operating pressure,
check the system for air leaks. Soap test all joints and fitting. To maintain desired
dew point, any leaks detected must be fixed, especially those on the outlet side of
the dryer.
• Make sure that the purge adjustment valve is open and air outlet shut off valve (if
equipped) is closed.
• For dryers equipped with a dew point monitor, remove the dew point monitor
sensor from the electrical enclosure and install in the sensing block, located
beside the enclosure and attach the sensor cable to the sensor.
• On dryers equipped with the Moisture Load Control option, verify that the Moisture
Load Control switch is in the OFF position to allow standard cycling at start-up.
• Turn on dryer disconnect switch (supplied by customer) to apply power to the
dryer.
• For the first 30 seconds that the dryer is energized, both purge valves will remain
closed. After 30 seconds, the left tower purge valve will be opened and depressurization of the left tower will occur.
• With a voltmeter, check the power connections for the correct voltage shown on
the dryer serial nameplate.
• Close and secure all electrical panel covers.
• When the dryer is energized, the Power-on Light and Right Tower Drying Light will
be illuminated. When electrical circuit has been energized, the Solid State Timer
will start automatically. See Section 6 for logic operating sequence.
• Following depressurization, adjust purge valve as described in Section 6.4
At initial start-up, check the dryer operation for one or two cycles, especially at
the time of the tower shift. Verify that all systems are operating in their proper
order and sequence. If the dryer is not functioning properly, contact distributor or
ZEKS Technical Service.
NOTICE
For dryers equipped with the optional NEMA 4 / DPC™ Package, refer to the
NEMA 4 / DPC™ Package Technical Manual Supplement prior to starting dryer.
NOTICE
12
• If the dryer has been in storage or off for an extended period of time, the Blue
Moisture Indicator may be gray, the High Humidity Alarm (if equipped) may be
activated and the dew point display (if equipped) may indicate a high dew point.
Depending upon the duration of idle time, it may take anywhere from one to
twelve hours for the alarm condition to go out, the BMI to return to its normal blue
state and the dew point to drop.
• Slowly open the outlet valve to gradually pressurize the down stream piping
• On dryers equipped with Moisture Load Control, the Moisture Load Control switch
may be turned “ON” to save purge air as described in Section 6.11.
When opening the outlet valve, insure drying tower gauge maintains line
pressure. Allowing pressure to drop in the dryer will result in an overflow
condition.
NOTICE
-80° F and -100° F dryers require flow through the dryer to lower the pressure
dew point to design levels. Failure to permit air flow through dryer (deadheading) will result in elevated outlet dew points. Once air is permitted to flow
through the dryer, the pressure dew point will gradually reduce to design levels.
NOTICE
13
8. MAINTENANCE AND SYSTEM CHECK
8.1 SCHEDULED MAINTENANCE
DAILY MAINTENANCE FUNCTIONS:
•Check and record inlet pressure, temperature and flow. Verify that it is
within specifications.
•Check tower pressure gauge readings within operating tolerance.
•Check operation for proper dryer cycling, depressurization and repressurization.
•Check that the prefilter drain is operating properly and that there is no condensate
discharged from purge mufflers.
•Verify that pressure in purging tower is 10 PSIG or less. If higher, muffler replacement is recommended. (Section 8.5)
•Verify that prefilter and afterfilter differential pressure is within operating limits.
Change as required. (Section 8.2)
•Check the Blue Moisture Indicator. Make sure air is bleeding through the indicator.
The indicator will be blue when air is dry.
SEMI-ANNUAL MAINTENANCE FUNCTIONS:
•Check outlet dew point.
•Check pilot air filter element and clean or replace as required.
•Replace prefilter and afterfilter elements and / or cartridges.
ANNUAL MAINTENANCE FUNCTIONS:
•Check desiccant and replace if necessary.
•Inspect and clean pilot air control solenoid valves, check valves and diaphragm
valves. Rebuild and / or replace as required.
•Test lights and switches, replace as necessary.
•Test electrical components, replace as necessary.
EVERY TWO YEARS:
•Replace diaphragm and seal kits on purge and switching diaphragm valves.
EVERY THREE - TO - FIVE YEARS:
•Replace desiccant.
•Rebuild purge and switching diaphragm valves (Preventative)
•Replace Check Valves (Preventative)
14
8.2 Prefilters and Afterfilters
• Prefilters - The cartridges of the prefilter must be changed as often as required to
prevent contamination of the regenerative dryer's desiccant bed.
The prefilter and automatic drain must be checked daily. To prolong filter cartridge
life, it is recommended that a mechanical air / moisture separator be placed
immediately before the prefilter.
• Afterfilters - The purpose of the afterfilter is to remove residual desiccant dust..
Depending upon equipment application and usage, frequency of filter element
change will vary. It is recommended to change filter element every six months as
a minimum.
8.3 Pilot Air Control Solenoid Valves
The length of time the pilot air valves can reliably operate without replacing is
dependent upon the type of dryer and the dryer’s operation. On ZEKS -40°F dew
point dryers, replacing the valves is recommended every 60 months. Given the
difference in cycle times for -80°F and -100°F units, these dryers should have their
pilot valves replaced every 30 months.
8.4 Muffler Changeout Procedure
• Depressurize the dryer turn control power off.
• Replace muffler.
• Follow Start-up procedure described in Section 7.6.
• Turn control power back on.
Should the drying system be overloaded and/or malfunctioning, causing high
pressure drop, afterfilters will prematurely plug. This problem can be avoided
by frequent inspection and proactive replacement of cartridges.
NOTICE
To avoid injury, depressurize dryer before performing any service.
WARNING
15
8.5 Purge and Switching Diaphragm Valves
These valves have two control ports; one on top and the other on the back side.
• Normally Open (N.O.) Valves: For N.O. inlet or repressurization valves, control air
is supplied to the top port. The back side port exhausts out the bottom side of the
diaphragm. If air leaks continuously when control air is supplied to the valve, the
internal seals are leaking and must be replaced.
• Normally Closed (N.C.) Valves: For N.C. purge valves, the top port is plugged.
Control air is supplied to the back port. If air vents out of the back port continuously when the solenoid is de-energized, it will exhaust through the top of the
solenoid. If this condition is observed, the internal seals are leaking and must be
replaced.
8.6 Outlet Check Valves
Outlet check valves sealing can be verified by depressurizing the dryer and slowly
applying pressure to the outlet. The valves should seal and prevent air from
pressurizing the towers. If a tower begins to pressurize, the check valve on that
side requires replacement.
8.7 Desiccant Changeout Procedure
When it becomes necessary to replace the desiccant in the towers, or on units that
are shipped without the desiccant installed, observe the following procedure:
• The standard units are furnished with fill and drain ports on each desiccant tower.
Remove the caps on both ports.
• To assist in getting the desiccant to flow from the tower, insert a small rod in to the
drain port as necessary. This may be required as the desiccant is packed into the
towers which may interfere with the desiccant flow from the towers.
To avoid injury, depressurize dryer before performing any service.
Be sure to wear respiratory protection during the draining and filling process to
minimize inhalation of desiccant, as desiccant will produce dust during this
procedure.
CAUTION
WARNING
16
• Retainer screens, located at the inlet and outlet piping connections of the tower,
are removable on all models. It is suggested that these screens be removed and
cleaned at the time of desiccant changeout. These screens can be accessed by
disconnecting the upper and lower manifolds from the dryer towers.
• After cleaning the retainer screens, replace screens and reattach the outlet port
plug.
• With the fill port plug removed, fill the dryer tower with the appropriate grade and
size desiccant. For those dryers that are shipped without desiccant installed,
using the fill kit provided with the dryer will facilitate filling the desiccant in the
tower. The level of the desiccant should be below the top retainer screen as
shown on the Desiccant Fill Chart below.
• Once the towers have been filled, replace the fill port plug on each tower.
• Any connections disturbed in the desiccant changeout process should be leak
tested prior to re-commissioning the dryer.
DESICCANT
FILL CHART
17
PROBLEM
Elevated dew point
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.
No pilot air.
Pilot-operated diaphragm
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 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” corrective 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.
Check pilot air-line. Check that
control airline filter is clean.
Inspect and replace seals as required.
9. TROUBLESHOOTING
Refer to maintenance descriptions in Section 8 as required for trouble shooting
procedures.
18
CORRECTIVE ACTION
Check that repressurization circuit is
sending control signal.
Check purge valve and its solenoid
valve.
Check purge valve and its solenoid
valve.
Check purge valve and its solenoid
valve. Repair and replace if
necessary.
Check that repressurization circuit is
sending control signal.
Purge muffler is dirty; replace.
Check inlet valve and outlet check
valves. Verify inlet valve is closed to
purging tower (0 psig tower).
Reset when right tower is on line.
PROBLEM
Dryer fails to
pressurize.
Dryer depressurizes
too rapidly.
Dryer fails to purge.
Excessive back
pressure in regenerating tower (above 5
psig)
Right tower
excessively high
pressure at the purge
gauge.
PROBABLE CAUSE
Faulty purge valve.
Purge valve does not close;
dryer repressurizing through
inlet valve.
Purge valve does not open.
Purge valve stuck in closed
position.
Purge muffler does not pass
air.
Purge muffler passes too
much air. Air is leaking
across valve.
Improper calibration.
19
10. PURGE CHARTS
Purge Orifice - 9/64 "
90ZPA Setting - 48 psig @ 14 SCFM
0
2
4
6
8
10
12
14
16
18
0 10203040506070
Purge Meter Setting - psig
Purge Air Flow - SCFM
Purge Orifice - 5/32"
120ZPA Setting - 53 psig @ 19 SCFM
0
2
4
6
8
10
12
14
16
18
20
22
0 10203040506070
Purge Me ter Se tting - psig
Purge Air Flow - SCFM
Purge Ori fic e - 3/16"
160ZPA Setting - 50 psig @ 26 SCFM
0
5
10
15
20
25
30
35
0 10203040506070
Purge Meter Setting - psig
Purge Air Flow - SCFM
Purge Orifice - 7/32"
200ZPA Setting - 42 psig @ 30 SCFM
0
5
10
15
20
25
30
35
40
45
0 10203040506070
Purge Meter Setting - psig
Purge Air Flow - SCFM
Purge Orifice - 1/ 4"
2
50ZPA Setting - 42 psig @ 40 SCFM
0
5
10
15
20
25
30
35
40
45
50
55
60
0 10203040506070
Purge Meter Setti ng - psig
Purge Air Flow - SCFM
Purge Orifice - 9/ 32"
300ZPA
Setting - 40 psig @ 48 SCFM
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
0 10203040506070
Purge Meter Setting - psig
Purge Air Flow - SCFM
20
Purge Orifice - 5/16"
400ZPA
Setting - 45 psi g @ 65 SCFM
0
10
20
30
40
50
60
70
80
90
0 10203040506070
Purge Meter Setting - psig
Purge Air Flow - SCFM
Purge Ori fice - 3/8"
500ZPA Setting - 35 psi g @ 81 SCFM
0
10
20
30
40
50
60
70
80
90
100
110
120
130
0 10203040506070
Purge Me ter Setting - psig
Purge Air Flow - SCFM
Purge Orifice - 3/8"
600ZPA
Setting - 41 psig @ 93 SCFM
0
10
20
30
40
50
60
70
80
90
100
110
120
130
0 10203040506070
Purge Mete r Setti ng - psig
Purge Air Flow - SCFM
Purge Orifice - 7/16"
800ZPA
Setting - 46 psig @ 130 SCFM
0
20
40
60
80
100
120
140
160
180
0 10203040506070
Purge Meter Setting - psig
Purge Air Flow - SCFM
Purge Orifice - 1/2"
1000ZPA
Setting - 43 ps ig @ 162 SCFM
0
20
40
60
80
100
120
140
160
180
200
220
0 10203040506070
Purge Meter Setting - psig
Purge Air Fl ow - SCFM
Purge Ori fic e - 9/16"
1200ZPA
Setting - 41 psig @ 195 SCFM
0
30
60
90
120
150
180
210
240
270
300
0 10203040506070
Purge Meter Setting - psig
Purge Air Flow - SCFM
Purge Orifice - 5/8"
1500ZPA
Setting - 41 psig @ 243 SCFM
0
30
60
90
120
150
180
210
240
270
300
330
360
0 10203040506070
Purge Meter Setting - psig
Purge Air Flow - SCFM
Purge Orifice - 5/ 8"
1800ZPA
Setting - 51 psig @ 292 SCFM
0
30
60
90
120
150
180
210
240
270
300
330
360
0 10203040506070
Purge Meter Setting - psig
Purge Air Flow - SCFM
Purge Orifice - 3/4"
2100ZPA
Setting - 40 psig @ 340 SCFM
0
50
100
150
200
250
300
350
400
450
500
0 10203040506070
Purge Me ter Se tting - psig
Purge Air Flow - SCFM
Purge Orifice - 3/ 4"
2700ZPA
Setting - 53 psig @ 438 SCFM
0
50
100
150
200
250
300
350
400
450
500
0 10203040506070
Purge Meter Setting - psig
Purge Air Flow - SCFM
Purge Orifi ce - 7/ 8"
3300ZPA
Setting - 47 psig @ 535 SCFM
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
0 10203040506070
Purge Meter Setting - psig
Purge Air Fl ow - SCFM
Purge Orifice - 1"
4000ZPA
Setting - 44 psig @ 649 SCFM
0
100
200
300
400
500
600
700
800
900
1000
0 10203040506070
Purge Mete r Setti ng - psig
Purge Air Flow - SCFM
21
Purge Ori fice - 1"
5000ZPA
Setting - 56 psig @ 811 SCFM
0
100
200
300
400
500
600
700
800
900
1000
0 10203040506070
Purge Meter Setting - psig
Purge Air Flow - SCFM
22
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