AirTek TW15 Instruction manual

HEATLESS DESICCANT
COMPRESSED AIR DRYER
MODELS TW10 - TW55
INSTALLATION, OPERATION
& MAINTENANCE MANUAL
Service Department
1-800-451-6023
Cost: $ 5.00

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AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
Let us take this opportunity to introduce our company.
AIRTEK is an innovative manufacturer of industrial equipment for compressed air
systems.
Our product line includes natural gas dryers, fluid coolers, water separators,
air filters, refrigerated air dryers, and heatless and heat reactivated desiccant
air dryers. Our products can be found in all corners of the world.
No effort has been spared to provide a comprehensive instruction manual for
the use of the AIRTEK Dryer. Information is given not only for the user, but also
for the technical personnel who may repair the dryer in the event that this is ever
necessary. It is recommended that all who will have responsibility for the dryer
carefully read all sections of this manual before commencing with the installation.
The most important step is for you as a customer is to call us first at
1-800-451-6023 if you are experiencing a problem with your dryer.
If there is a question regarding this manual or our warranty policies
and procedures, please call. We would be happy to speak with you.
Thank you for choosing AIRTEK products.
AIRTEK Service Department
DEAR CUSTOMER
DRYER SPECIFICATIONS

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AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
TABLE OF CONTENTS:
1. A. Inspection&Installation................................................................................................. Pg. 4
B. DryerLocation
C. Installation
2. A SafetyPrecautions......................................................................................................... Pg. 4
3. A. Startup........................................................................................................................... Pg. 5
4. A. ShutdownProcedure...................................................................................................... Pg. 5
5. A. TheoryofOperation....................................................................................................... Pg. 5 - 6
6. A. Sequence ofOperation................................................................................................... Pg. 6
B. OperationalNotes
7. A. FixedTime Cycles........................................................................................................... Pg. 7
B. DemandCycles
8. A. PurgeFlowCalculations................................................................................................. Pg. 7 - 8
B. PurgeFlowAdjustment
C. DryerOutletFlow
9. A. Dryers EquippedwithPowerLoc.................................................................................... Pg. 8
10. A. MaintenanceProgram.................................................................................................... Pg. 8 - 9
11. A. PartsDescription............................................................................................................. Pg. 9
B. RecommendedSpareParts
12. A. DesiccantReplacement.................................................................................................. Pg. 10
13. A. DryerCapacityChart...................................................................................................... Pg.10
14. A. ServiceInstructions........................................................................................................ Pg. 11
B. EquipmentReturnInstructions
C. Warranty
D. Disclaimer
15. A. Trouble Shooting Guide .................................................................................................. Pg. 12 - 13
16. Drawings
A. RecommendedInstallationDrawing............................................................................... Pg.14
B. Flow:TW10-TW15...................................................................................................... Pg. 15
C. Flow:TW25- TW55 ...................................................................................................... Pg. 16
D. WiringDiagram:Standard Dryer .................................................................................... Pg. 17
17. Charts
A. DryerServiceRecord..................................................................................................... Pg. 18
B. PurgeCharts.................................................................................................................. Pg.19
C. AnalyzingChart.............................................................................................................. Pg. 20

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AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
PRIOR TO INSTALLATION OR START-UP OF DRYER,
THIS ENTIRE MANUAL SHOULD BE READ & UNDER-
STOOD.
1. A. INSPECTION:
All Dryers are tested and inspected at the factory prior to
shipping. Inspect the dryer carefully upon arrival and note
any damage on the freight bill. Uncrate and inspect for
concealed damage. File claims with the carrier immediately
and notify AIRTEK sales department.
1. B. DRYER LOCATION:
Locate the dryer in an area accessible for maintenance.
The area should be clean, cool, well lighted, and have a
level, vibration free floor. Ambient temperature should be
between 35ºF and 100ºF. Dryer should have a minimum
36” clearance on all sides. See dimensional print for
specific clearance requirements.
1. C. INSTALLATION:
(See typical installation drawing)
Make the following connections:
1. Inlet piping, including an isolation valve.
2. Outlet piping, including an isolation valve.
3. Coalescing Pre-filter and Particulate After-filter.
4. Auto Drain on Pre-filter.
5. Bypass piping if desired. A bubble tight valve
should be used for bypass.
6. Make required electrical connections to control box.
Refer to applicable drawings. Note: Customer to
provide short circuit protection for dryer.
7. Access ports should be provided upstream and
downstream of the dryer for dewpoint, pressure and
temperature checks.
8. All piping should be adequately supported and at
least of equal size to the dryer connections.
9. To reduce maintenance & increase dryer efficiency,
the exhaust ports can be piped to a location where the
exhaust mufflers are not required.
NOTE: All piping & electrical connections should be checked
to insure they have maintained their integrity during shipping
and installation.
IMPORTANT! Desiccant dryers are designed to remove
water VAPOR only!
The air to be dried must pass through a Coalescing Pre-
filter for removal of entrained condensate and oil to prevent
fouling of the desiccant. Liquid condensate entering the bed
will lead to overloading of the dryer, poor dew point perfor-
mance, & rapid deterioration of the desiccant. Oil entering
the desiccant bed may permanently reduce the capacity of
the desiccant.
An Automatic Drain is required on the Pre-filter and all other
upstream collection points to remove condensate.
A Particulate After-filter should be provided to prevent
desiccant dust from traveling down stream. Desiccant dust
may cause contamination & excessive wear to equipment.
Before any attempt is made to operate the AIRTEK dryer,
the operator should thoroughly read and understand this
instruction manual. Improper operation will cause poor
results from the dryer.
Periodic checking of the dewpoint just downstream of the
dryer is the best indication of whether the dryer is perform-
ing as expected. For a rough indication of performance a
Color Change Moisture Indicator is provided as standard
equipment. The indicator will be green when the outlet air
is dry, and white when the outlet air is wet. Optionally
available is a High Humidity Alarm or a PowerLoc (Digital
Dewpoint Monitor & Demand Cycle Controller).
2. A. SAFETY PRECAUTIONS:
Failure to observe any
of the following precautions could result in severe bodily
harm and/or damage to equipment.
* Use EXTREME CAUTION when working in the vicinity
of the dryer.
* Relieve pressure before servicing dryer or associated
equipment.
* Disconnect power before servicing dryer.
* Use ear and eye protection when in the vicinity of the
dryer or exhaust ports, especially if the dryer is being
operated without mufflers. Even when mufflers are
used, a tower blowing down to atmosphere will raise
particles, create more noise than during “normal”
operation and may startle an individual not used to this
portion of the operation.
* In the case of an overpressure situation there is a
safety relief valve on each tower designed to protect
the equipment. If these end up pointed in a hazardous
direction after dryer installation, they should be piped
to a safe location
* Automatic or manual drain valves will eject water, oil,
particles and air under partial pressure when operated.
Proper precautions must be taken.
* Condensate drainage from compressed air systems
may contain oil or other contaminants. Follow all
applicable regulations for safe handling and disposal.
* Various component failures could theoretically cause
large air loss and subsequent pressure drop. Preven-
tive maintenance should be performed to reduce the
likelihood of this. If this occurs, bypass the dryer
immediately to restore flow and pressure.
* Activated Alumina dust is considered a nuisance dust.
Proper precautions should be taken when handling
desiccant. For more information and for other types of
desiccant, refer to applicable Material Safety Data
Sheet.
* For disposal of used desiccant refer to the applicable
Material safety Data sheet and all applicable regula-
tions. Note that desiccant contaminated with oil or
other foreign substances may be covered under
disposal regulations for the contaminant.

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AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
3. A. START-UP
Please read and understand the entire manual before
operating the dryer.
Check and read over wiring diagram that pertain to your unit
and make sure the correct power supply is connected, but
do not energize circuit at this time. Provide proper short
circuit protection. Follow all applicable codes.
Before starting the dryer your compressor should be
running, your air system pressurized and the dryer by-
passed and not yet pressurized.
SLOWLY open the inlet isolation valve admitting com-
pressed air to the dryer. It is important to pressurized the
dryer slowly to prevent fluidization of the desiccant bed.
The dryer outlet isolation valve should be closed at this
time.
SLOWLY open dryer outlet isolation valve. At this point all
valves are in their “normal” positions, air is flowing through
both towers and downstream.
Close the dryer bypass valve. Bypass valve must be bubble
tight to prevent moisture from migrating around the dryer
and contaminating the dry air outlet.
It is recommended that the dryer be started without the
mufflers installed. This will expedite removal of excess
desiccant dust and prevent premature clogging of the
exhaust mufflers.
CAUTION: USE EAR AND EYE PROTECTION WHEN
OPERATING DRYER WITHOUT MUFFLERS. EXCESSIVE
NOISE WILL BE CREATED. DUST AND PARTICLES
FROM THE SURROUNDING AREA MAY BECOME
AIRBORNE. OPERATION WITHOUT MUFFLERS EX-
CEEDS OSHA LIMITS.
Checking the cycle setting. It should normally be set to the
standard 10-minute cycle.
Energize the electrical circuit. The dryer will begin to cycle.
At this point one tower will exhaust its air to atmosphere.
See cautionary statement above.
Check and adjust the setting of the purge flow in accor-
dance with the specifications for your dryer. See Section 8.
Purge flow is typically 15% of design flow for the dryer. Note
that even if you are operating under a light load the purge
can not be reduced if you are operating in the PowerLoc
mode, CycleLoc mode, or a fixed timed cycle other than the
standard 10-minute cycle.
Never service the Dryer or Filters without first relieving
pressure.
Check all air connections for leaks and tighten as required.
Downstream air leaks will affect dewpoint. Bypass air leaks will
affect dewpoint. Only soft seat bypass valves may be used.
Dryer will not perform without proper pre-filtration, conden-
sate drainage, and purge flow. Dryers may require up to 48
hours of operation to reach normal operating dewpoints.
Therefore, indicators and/or alarms should not be recog-
nized until that time. Applications requiring dewpoints lower
than –40, or with nonstandard operating conditions, may
require additional time to reach equilibrium. Exhaust valves
and/or exhaust mufflers may have to be cleaned due to
dusting in shipping and start-up.
4. A. SHUTDOWN PROCEDURE:
1. Allow the dryer to reach a repressurization step & fully
repressurize.
2. While fully repressurized, remove power from the dryer.
After shutdown airflow will continue through one tower, if
there is downstream demand, the dryer should be immedi-
ately bypassed to prevent loading of the beds while the
dryer is out of service.
3. Always remove all pressure & disconnect all power
before servicing the dryer.
4. If a PowerLoc is installed and the dryer will be out of
service for an extended period of time, remove the probe
and store in a safe, dry location. The probe will be dam-
aged if exposed to prolonged periods of saturation condi-
tions.
No other special procedures are required.
5. A. THEORY OF OPERATION:
Adsorption is the process of removing water VAPOR from
the air to be dried. All condensed liquid water should be
removed from the inlet air stream prior to reaching the dryer
by suitable separators, traps, filters and drains. The dryer
can not be burdened with liquid condensate carry-over.
All Desiccants are adversely affected by oil, oil aerosols,
dirt, rust, scale or liquid water. Effective pre-filtration in
conjunction with automatic condensate drainage is a must
for proper dewpoint depression and long desiccant life.
The saturated inlet air is alternately cycled through each of
the two desiccant beds. One bed is “on-line” at full line
pressure and flow, adsorbing water vapor from the satu-
rated inlet air. This is the drying bed. The other bed is “off-
line” at atmospheric pressure (0 PSIG) being regenerated
by a depressurized portion of the dried outlet air (purge air).
This is the regenerating bed.
The quantity of purge air for a standard pressure dryer is
approximately 15% of inlet design flow. This air is taken
from the dry air outlet, directed through the purge flow
controls, desiccant bed, and finally exhausted to atmo-
sphere to accomplish regeneration. Purge air consumption
is typically the largest cost involved with operating a
heatless desiccant air dryer. (Purge air is “nonrecoverable”
and the air system in question must be designed to allow for
this usage.)

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AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
IMPORTANT: Just as the dryer is designed to remove only
water vapor, the moisture being purged from the saturated
regenerating bed will also be exhausted in VAPOR form. At
no time should you see liquid water being ejected from the
dryer! The only water you might see is a small amount of
condensate forming at the exhaust due to the Joule-
Thomson cooling effect created by the depressing air.
Prior to switching a freshly regenerated bed on-line to
become the drying bed, it must be slowly pressurized from
atmospheric pressure to line pressure. This step is called
repressurization. Repressurization prevents bed fluidization
(lifting) and associated dusting.
Following repressurization, the beds switch functions with
the fresh bed now drying and the saturated bed being
regenerated.
Note that one bed is always on-line drying. Also note that
purge air is always being consumed except during
repressurization.
This cycle will continue automatically unless the dryer is
shut down, operated in the CycleLoc mode, or equipped
with a demand cycle controller (PowerLoc).
6. A. SEQUENCE OF OPERATION:
The above sequence is controlled by a Solid State Timing
and Relay circuit (Sequence Annunciator) which in turn
controls a 4-way solenoid valve (S1: inlet switching valve)
and a 2-way NC solenoid valve (S2: purge stop/exhaust
valve).
STEP 1: LEFT DRYING, RIGHT REGENERATING
The inlet switching valve (S1) is in its default non-
energized position, directing all the wet inlet air to the left
tower. The air is dried as it passes through he desiccant bed
at system pressure, typically 100 PSIG. As the air exits the
tower fully dried, the bulk of the air is directed downstream
via the outlet check valves.
Approximately 15% of the dried air is directed to the right
tower via the purge controls. This purge or regeneration air
is reduced to atmospheric pressure (0 PSIG) by the time it
enters the right tower. This super dry, low pressure purge
air flows down through the desiccant bed, stripping accu-
mulated moisture. It is directed via the inlet-switching valve
through the purge stop solenoid (S2), which is energized
and open. The moisture laden purge air exists to atmo-
sphere through the exhaust muffler.
On TW10 & TW15 models the purge controls consist solely
of a bi-directional flow needle valve connecting the outlet of
each tower. The needle valve is adjusted to obtain the
required purge flow.
On TW25, TW40, & TW55 models the purge control
system consists of a purge filter, needle valve, pressure
gauge, orifice, and two purge check valves. The needle
valve is adjusted to obtain the specified purge pressure,
which equates to the proper purge flow.
STEP 2: LEFT DRYING, RIGHT REPRESSURIZING
The purge stop solenoid (S2) is de-energized and returns to
its normally closed position. This prevents the purge air
from exhausting to atmosphere, resulting in the right tower
and the purge system being pressurized to system pres-
sure.
STEP 3: LEFT REGENERATING, RIGHT DRYING
Simultaneously the inlet switching valve (S1) and the purge
stop solenoid (S2) are energized. Energizing S1 shifts the
inlet switching valve to direct the inlet flow to the right tower
where it is dried as it passes over the freshly regenerated
desiccant bed. S2 opens as it is energized “blowing down”
the left tower. Purge air now flows over the left tower,
stripping the moisture from the desiccant that was adsorbed
when the left tower was on-line drying.
STEP 4: LEFT REPRESSURIZING, RIGHT DRYING:
The purge stop solenoid (S2) is de-energized and returns to
its normally closed position. This prevents the purge air
from exhausting to atmosphere, resulting in the left tower
and the purge system being pressurized to system pres-
sure.
NOTE: The Purge Gauge (middle gauge TW25, 40, 55)
should read purge pressure, except during repressurization.
Purge flow is calculated by the Purge Formula in this
manual and checking the proper chart. Purge pressure for
standard inlet design conditions is listed on the specifica-
tions page. For other than standard or design conditions
use the purge formula and charts for purge flow/pressure
calculation, or consult the factory.
6. B. OPERATIONAL NOTES:
A desiccant dryer should never be suddenly pressurized or
depressurized. This will cause fluidizing and dusting.
After start-up, some dusting may occur. This will diminish
with time. Some dusting may occur with normal operation.
The Exhaust Muffler should be cleaned regularly and an
Afterfilter should be used.
Flow direction is Upflow Drying – Downflow Purge.
Switching Failure alarm is optional and the Dryer must be
operating over 70 PSI for proper function of the alarm.
During a power loss situation, the exhaust valve will close
preventing purge air loss and allowing the system to remain
pressurized. Inlet air is able to flow through one tower and
downstream.
The standard AIRTEK dryer has a design pressure of 150
PSIG. In good practice the normal working pressure should
be below 150 PSIG to prevent the safety valve from blowing
off.

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AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
7. A. FIXED TIME CYCLES
The Airtek heatless dryer is equipped with a cycle selection
switch. The dryer can be set to one of two standard fixed
time cycles; Standard 100% load 10 minute cycle, or Short
cycle –80ºF dew point 5 minute cycle. Complete cycle times
are given below.
FIXED CYCLE TIMES: (Time in Minutes: Seconds)
The standard cycle is most commonly used. It is designed
for full load or constant use applications requiring a –40
dewpoint.
The short cycle will provide a –40 to –80ºF dew point when
operating at or below design moisture loading conditions.
Always set the purge as if you had full inlet flow when using
this cycle. Note this cycle is not designed to compensate
for overloading of the dryer.
7. B. DEMAND CYCLES
CycleLoc and PowerLoc demand cycles are also available.
These cycles offer improved operating efficiency over fixed
time cycles for applications requiring a –40 dewpoint and
that will see lighter than design moisture loadings. Demand
cycles reduce total purge consumption and thus reduce
energy usage by tailoring the cycle to actual loading, vs.
fixed cycles, which assume 100% design loading. Demand
cycles can not accommodate for heavier than design
loadings!
The CycleLoc feature is built in to every model. It can be
used to interface the dryer with the compressor. The dryer
must be able to handle at least full flow of the compressor
and the receiver should ideally be located downstream of
the dryer. A dry (unpowered) contact closure across the
CycleLoc terminals on the Sequence Annunciator will cause
the dryer to immediately pause it’s cycle & stop purging.
The contact closure needs to correlate with the compressor
stopped or unloaded. When the contact opens the dryer
cycle will resume where it left off. Typically a contact on the
compressor pressure control is utilized. If a dry normally
open (with compressor running) contact is not available, an
auxiliary relay will need to be added. The jumper JP1 must
be installed for correct CycleLoc operation. Please consult
the factory for more information.
The PowerLoc demand cycle is available only when the
PowerLoc Demand Cycle Controller option is purchased.
Which this option the actual outlet dewpoint of the dryer is
monitored to ensure the online bed is fully utilized prior to
regeneration. Please see Section 9 for further details.
PowerLoc & CycleLoc cycles can not be used together!
Please consult factory to insure proper use of any of the
nonstandard cycles.
8. A. PURGE FLOW CALCULATIONS:
For standard inlet conditions use chart to determine
purge flow. Standard conditions are 100 PSIG, 100ºF, and
design inlet flow.
For nonstandard inlet conditions use the following calcula-
tion to calculate purge flow (inlet pressures between 60 &
250 PSIG only.):
Purge flow = Inlet Flow (SCFM) X 14.7 X 1.15
Inlet Pressure (PSIG) + 14.7
LOWEST operating pressure and MAXIMUM inlet flow
should be used in this calculation.
After calculating the required purge flow, locate the correct
orifice size for your unit on the purge chart, (Page 19).
Read down this column until you locate the required purge
flow. If the exact flow is not listed go to the next highest.
Read across the column to the far left to determine the
correct purge pressure setting.
If operating in the PowerLoc mode, CycleLoc mode or any
fixed time cycle other than the standard 10 minute cycle;
design purge flow must be used.
For a 0º Dewpoint, reduce purge by 25%. Maximum
permissible purge flow reduction is 50% of purge flow
calculated for design inlet conditions.
8. B. PURGE FLOW ADJUSTMENT:
Purge adjustment must be made with the dryer online, with
one tower drying and one tower regenerating. Insufficient
purge will cause poor performance and eventually result in
desiccant degradation.

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AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
Models TW10 & 15 are provided with a needle valve for
purge adjustment. A purge indicator for this low a flow is
not practical. The purge flow should be set to feel. As a
minimum it must be set high enough so that the dryer
achieves full repressurization prior to switching. If perfor-
mance is unacceptable, increase purge flow. Purge flow
can be determined if there is a system flow meter in place,
via addition or subtraction from the flow meter.
Models TW25, 40 & 55 are provided with a needle valve for
adjustment and an orifice and pressure gauge for metering
and indication. Adjust the needle valve so that the purge
(center) pressure gauge reads the correct purge pressure as
determined above. The setting may vary slightly with line
pressure.
Some special models are equipped with flow meters that
read purge directly in SCFM. Adjust the needle valve so
that the flow meter reads the correct purge flow..
8. C. DRYER OUTLET FLOW:
Dryer outlet flow is equal to the dryer inlet flow minus the
purge flow.
9. A. DRYERS EQUIPPED WITH POWERLOC:
The PowerLoc is a Digital Dewpoint Monitor and Demand
Cycle Controller. The sensor is a thin film gold aluminum
oxide design. The PowerLoc monitors the outlet pressure
dewpoint of the dryer and digitally displays it.
The Demand Cycle Control feature tailors the dryer cycle to
actual loading conditions, maximizing energy usage.
Without the PowerLoc the cycle is fixed and “worst case”
design conditions are assumed.
The Demand Cycle is accomplished by providing a discrete
dry contact closure across the CycleLoc terminals on the
Sequence Annunciator. The Variable Cycle Switch must be
set to the 100% load setting and JP1 must be removed for
the PowerLoc to work!
If the dryer is maintaining a good dewpoint AFTER the first
five minutes of drying, the PowerLoc will override the fixed
cycle and keep the current tower on-line until it is saturated
to design loading (switchpoint valve), usually –40º. If this
occurs the offline bed, which has just finished being
regenerated, will repressurize and be ready to go on-line.
The CycleLoc light on the Sequence Annunciator and the
PowerLoc Mode light on the PowerLoc will be on at this
time. Once the dewpoint degrades to the switchpoint valve,
the freshly regenerated bed will go on-line, and the satu-
rated bed will depressurize and begin regeneration.
Note that the PowerLoc cannot shorten the cycle. The
drying tower will always be on-line a minimum of five
minutes and the regenerating tower will always undergo a
design regeneration cycle of 4 minutes and 15 seconds.
Thus the PowerLoc can only compensate for “under”
loading, not overloading conditions.
If there is any error with the PowerLoc, the dryer will default
to the fixed time cycle. There is also a PowerLoc On/Off
switch located in the control enclosure. If this switch is
turned off the dryer will operate in the fixed time cycle. The
PowerLoc will continue to display dewpoint.
The PowerLoc is fully programmed and wired at the
factory if ordered with the dryer. All that is normally
required is sensor installation. The sensor should be
installed (without cable attached) only after the dryer has
cycled 3 or more times and the sample line has been “blown
out”. Do not allow the probe to bottom out in the sample
line. Do not tighten ferrule on sensing tip. Hand-tighten
nut, wrench tighten 1-1/2 turns. Open the probe isolation
valve slowly to full open position. This allows operation at
full line pressure for correct reading of pressure dewpoint. A
coil of capillary tubing is provided to allow a small sample
flow over the sensor and prevent ambient moisture from
infiltrating the system. Check the bleed periodically to
ensure it is not clogged.
Following sensor installation allow the sensor to stabilize at
line pressure for four hours prior to attaching the sensor
cable.
Failure to follow the above precautions may result in sensor
failure not covered by warranty.
Upon installation the sensor may be saturated. Even if the
dryer is producing a good dewpoint, it will not be indicated
immediately as it will take a period of time for the sensor to
dry out and come to equilibrium with the system. The
sensor will also become saturated if the air system is shut
down and allowed to depressurize. Upon restart of the
system, the dewpoint may appear to be poor, even though
the dryer may be producing clean, dry, air.
Although the probe can be exposed to occasional, brief
periods of liquid saturation, it can not be exposed to
continuous wet conditions. If your dryer is overloaded and
saturated, or if it will be shut down for an extended period of
time; remove or isolate the probe until the problem is
resolved.
Refer to the separate PowerLoc Manual for additional
information.
10. A. MAINTENANCE PROGRAM:
DAILY:
1. Check dewpoint or humidity level, if instrumentation is
available. Any difficulty with the dryer will result in poor
dewpoint performance.
2. Check for correct purge setting and air flow from purge
exhaust.
3. Check gauge readings & sequence of operation
through complete cycle.
4. Check auto drain operation on Prefilter, Separator &
Receiver. A manual drain valve installed (in addition to
the automatic drain at these points will ease checking
of the automatic drains.
5. Ensure there is no backpressure in the regenerating
tower (Pressure = 0 PSIG).

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AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
WEEKLY:
1. Check differential pressure across prefilter & afterfilter
elements. Replace if required.
2. Check and maintain operating conditions; Pressure,
flow, and Temperature within the design parameters of
the dryer.
SEMI-ANNUALLY:
1. Inspect desiccant for physical condition. Desiccant
from a freshly regenerated bed should be white, dry to
the touch and of consistent size & shape. If desiccant
condition is in question, send a sample to AIRTEK for
analysis.
2. Check and clean mufflers. This may be required often
under certain conditions or if back pressure develops.
Mufflers may require replacement if severely clogged,
or after a few cleanings.
3. Replace prefilter and after filter elements
4. Clean automatic drain.
5. Replace purge filter element (TW25-55).
6. Check and Blowdown Safety Valves. Refer to
manufacturer’s instructions.
7. Clean dryer.
ANNUALLY:
1. Inspect and rebuild inlet and Exhaust Valves.
2. Return PowerLoc probe & chip for recall, if applicable.
Note: No lubrication is required.
11. A. GENERAL PARTS DESCRIPTION:
A. Desiccant – An adsorbent used for drying air or gases.
Proper quantity, size and type necessary.
B. Inlet Switching Valves – 4-way electric switching valve.
Directs inlet air to drying tower and purge air from regener-
ating tower to exhaust.
C. Exhaust Valve – Normally Closed solenoid valve used
to exhaust purge air, hold air in tower on line, and exhaust
air from tower ready to be regenerate.
D. Outlet & Purge (TW25-55) Check Valves – Valves that
allow full flow in one direction and no flow in the other are
used in conjunction with the inlet and exhaust valve to
accomplish desired flow of process and purge air.
E. Safety Relief Valves – Furnished on each tower to
protect the vessels from over pressure situations. Standard
setting is 150 PSIG.
F. Purge Exhaust Muffler – Furnished to reduce exhaust
noise during purge and blow down for personnel protection
and to comply with OSHA standards. Mufflers offer no
benefit to the operation of the dryer and are a maintenance
concern.
Consideration should be given to locating the exhaust in an
area where mufflers would not be required.
G. Purge Control Valve – Furnished to adjust & regulate
purge flow for regeneration.
H. Solid State Controller/Sequence Annunciator –
Furnished for cycle control. Outputs operate 2 electric
solenoid valves. Provides for variable cycle control.
Provides interface for CycleLoc control or optional
PowerLoc Demand Control. Has integral lights to provide
visual cycle indication. Has built-in autodrain control. All
hard wired connections including field power connection,
made to this board.
I. Tower Pressure Gauges – Furnished to read pressure
in each tower. On-line tower should read line pressure,
regenerating tower should read 0 psig.
J. Purge Flow Indicator (center gauge or flow meter
TW25-55) – Furnished to indicate and monitor proper purge
flow.
K. Purge Air Filter – Filters purge air, which is taken from
the dryer outlet, to protect the purge orifice and needle valve
from desiccant dust. Also protects PowerLoc probe where
applicable.
11. B. RECOMMENDED SPARE PARTS
DOMESTIC:
QTY DESCRIPTION
1 Outlet Check Valve or repair kit
1 Purge Check Valve or repair kit
2 Purge Filter Elements
2 Inlet Valve Repair Kits
1 Exhaust Valve
1 Solid State Control Assembly
1 Exhaust Muffler
2 Pre-Filter Elements
2 After-Filter Elements
1 Automatic Drain Solenoid
EXPORT:
QTY DESCRIPTION
3 Gauge, Pressure
1 Inlet Valve
1 Exhaust Valve
1 Outlet Check Valve & Repair Kit
1 Purge Check Valve & Repair Kit
4 Purge Filter Element
4 Inlet Valve Repair Kit
4 Exhaust Valve Repair Kit
1 Solid State Control Assembly
2 Exhaust Mufflers
4 Pre-Filter Element
4 After-Filter Element
1 Automatic Drain Solenoid
* Desiccant
*See chart next page.

Pg. -10-
AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
12. A DESICCANT REPLACEMENT:
CAUTION: Activated Alumina Desiccant dust is considered
a nuisance dust. Proper precautions should be taken.
Refer to Material Safety Data Sheet.
1. Remove pressure and power from dryer.
2. Open drain ports on bottom of tanks.
3. Catch desiccant in suitable container. Close drain ports
and open top fill ports.
4. Refill with recommended type, size and quantity of
desiccant. Rap sides of the chamber while filling, so
desiccant will pack tightly. Fill chambers only to within
three inches of the top. Some settling may be required
to fit specified amount in tank. One tank size may be
used for multiple models, do not be concerned if tank is
not full.
5. Consult Material Safety Data Sheet and all applicable
regulations for disposal of desiccant. Disposal of
desiccant contaminated with oil or other substances
may require different procedures than desiccant
replaced strictly due to aging.
NOTE: Use only AIRTEK Desiccant which is a high
capacity, high quality desiccant designed & sized for
AIRTEK Dryers.
MODEL DESICCANT (LBS./TOWER)
TW10 7
TW15 7
TW25 15
TW40 23
TW55 35
13. A. DRYER CAPACITY
CHECKING DRYER SIZE:
A. Determine operating pressure.
B. Determine input SCFM into dryer.
C. Read down the nearest operating pressure column until
you arrive at a rating equal to or greater than your require-
ment; then read to the left for dryer model.
PRESSURE
MODEL 60 80 100 120 140
TW10 7 8 10 12 13
TW15 10 12 15 18 20
TW25 16 21 25 29 34
TW40 27 35 42 49 57
TW55 39 50 60 70 81
Example: You want to dry 27 SCFM at 80 PSIG – go to the
80 PSIG column and read down to 35 (this is the first
number equal to, or greater than your requirement). Now
read the dryer model number to your left. A model TW40 is
required.
Sizing is approximate only. Consult factory for exact
sizing. Downsizing could cause pressure drop, bed
fluidization, or poor dewpoint performance due to low
contact time.
The above chart assumes 100ºF or less inlet air tempera-
ture. Due to generous bed sizing, most AIRTEK heatless
dryers can be operated at up to 120ºF at 100 PSIG and
rated flow. However, consult factory for any applications
over 100ºF.

Pg. -11-
AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
14. A. SERVICE
All service should be handled through an authorized
AIRTEK distributor. Any service performed during the first
year of operation without knowledge or consent of AIRTEK
will result in voiding of the warranty. AIRTEK will not
assume or accept responsibility for any expenses incurred
for repair of the dryer without our knowledge or consent.
In order to speed our service to you, should you need it,
please fill out the analyzing chart provided at the end of the
manual. If there is an operational problem with the dryer
and you do not know what the cause is, this chart must be
filled out completely and accurately. Always provide the
following whenever contacting a distributor or AIRTEK.
1. Dryer model number
2. Dryer serial number
3. Phone number and name of person to contact at
dryer location.
14. B RETURN OF DEFECTIVE EQUIPMENT:
All claims must be made within five days after receipt of
goods, if external damage is present. If order has been
filled correctly, we cannot allow the return of the goods
without our consent, and then only on a basis of a charge
for service and rehandling, plus transportation charges.
Transportation must always be prepaid. If it is necessary to
return a part to the factory for replacement or inspection, do
not fail to do the following.
1. Write or call the nearest sales and service office
advising what material you wish to return and why.
2. After receiving return material authorization complete
the following:
a. Tag package showing your name, address and return
material authorization number
b. Tag each article with part number and quantity.
c. Always give model and serial number of the dryer.
d. Always give invoice number on which the machine was
originally shipped.
3. All parts being returned for credit should be
handled same as above.
14. C. WARRANTY
AIRTEK air dryers are warranted against defect due to
faulty workmanship or parts for a period of one year from
date of shipment. This guarantee covers replacing such
parts as found defective due to defective material or
workmanship, only when such parts are returned to
AIRTEK, transportation prepaid and subject to our
inspection and approval. No liability is accepted for
consequential damages or reinstallation.
AIRTEK will not assume responsibility for contingent
liability through the alleged failure or failures of any of its
products or their accessories.
Bills for service, labor or other expenses that have been
incurred by the Buyer, their customer or agent, without
approval or authorization by the manufacturer will not be
accepted.
This warranty does not cover failure resulting from
improper installation and/or mounting design which
permits liquid water or other contaminants into the dryer
destroying the desiccant or allows excess vibration
causing breakage of parts due to material fatigue. This
warranty does not cover failure or leaking of valves due to
dust or dirt or any regular maintenance items such as
replacement filter elements.
To validate the warranty on your AIRTEK dryer, simply fill
out the WARRANTY REGISTRATION CARD enclosed
with the dryer, and mail it to the address on the card face.
Failure to do this could result in the refusal of warranty
should any service be necessary in the first year of
operation.
14. D. DISCLAIMER & LIMITATIONS
The company (AIRTEK) makes no other warranty of any
kind whatsoever, expressed or implied, and all warranties
of merchantability and fitness for a particular purpose are
hereby disclaimed by the company. The company shall in
no case be subject to any obligation or liability whatsoever
with respect to product or services manufactured or
furnished by it or any acts of omission relating thereto.
The remedy provided under this warranty shall be the
sole, exclusive, and only remedy available to the pur-
chaser. Under no circumstances shall the company be
liable for any special, indirect, incidental or consequential
damage, losses or delays however caused.

Pg. -12-
AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
Complaint:
DRYER NOT OPERATING:
FAILURE TO SWITCH ALARM (Optional):
OUTLET DEWPOINT HIGH:
MOISTURE DOWNSTREAM:
EXCESSIVE AIR LOSS ON REGENERATING TOWER:
EXHAUST VALVE LEAKING DURING
REPRESSURIZATION:
EXCESSIVE PRESSURE DROP:
15. A. TROUBLE SHOOTING GUIDE:
Possible Cause & Repair:
A: No Lights On:
- Blown control fuse: Replace fuse.
- No power: Apply correct power.
- Solid State Controller inoperative: Replace
B: Lights On, Dryer Does Not Switch:
- Dryer in PowerLoc Mode
- Dryer in CycleLoc Mode
- Time delay setting too short. Adjust properly.
- See dryer not operating
- Dryer not cycling: See Dryer not operating.
- Incorrect purge rate: Adjust purge flow.
- Capacity of dryer being exceeded: Adjust inlet
flow, pressure & temperature to within specified
operating parameters. High flow, low pressure or
high temperature will all adversely effect dryer
performance
- Liquid water present at dryer inlet: Check water
level in separators, receivers, prefilters &
operation of associated y-strainers and auto
drains. Check condition of filter elements or
check D.P. Gauges.
- Desiccant worn out, contaminated or insufficient
quantity: Replace or top off.
- Back pressure in regenerating tank: See below.
- Leaking bypass valve: Remedy.
- Undried air from another source mixing down
stream of dryer: Remedy.
- See Outlet Dewpoint High.
- Purge set too high. Check specifications &
adjust.
- Check valve leaking: Repair, clean or replace.
- Inlet valve leaking or not functioning: See Below
- Defective controller: Repair or replace.
- Valve dirty or defective: Clean or replace valve.
- False signal from control board: replace
- Prefilter dirty: Replace element
- Afterfilter dirty: Replace element
- Desiccant dirty: Replace Desiccant
- Excess flow: Reduce flow to within specs.

Pg. -13-
AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
Complaint:
UNIT DOES NOT FULLY REPRESSURIZE:
BACK PRESSURE IN REGENERATING TOWER:
INLET OR EXHAUST VALVES NOT FUNCTIONING:
NOTES:
Possible Cause & Repair:
- Purge rate too low: Adjust purge.
- Exhaust valves leaking: See above.
- Purge or repressurization orifice plugged: Clean
- Clogged mufflers: Clean, repair or replace.
- Check valves leaking: Clean, repair or replace.
- Purge flow too high: Adjust.
- Leaking inlet valve: See inlet valve not function-
ing.
- Bad seals or solenoid: Rebuild valves with
available kits or replace
- No output from controller: Replace fuse or
controller
- Valve dirty: Clean.
- When factory assistance is required always
provide model, serial number, full description of
problem and a completed analyzing chart.
- For trouble shooting PowerLoc, please consult
PowerLoc manual.
If at any time a problem develops, fill out a copy of
the analyzing chart. It is also good practice to fill out
a chart monthly. Keep these charts on file for
comparison purposes if a problem arises.
15. A. TROUBLE SHOOTING GUIDE (con’t):

Pg. -14-
AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
16. A. Sequence of Operation Diagram
RECOMMENDED INSTALLATION
CLEAN DRY, CONTAMINANT FREE AIR
(Note: Desiccant Dryers are designed to remove water VAPOR only)
(Liquid water and oil will damage desiccant)
WARNING: INCORRECT INSTALLATION WILL VOID WARRANTY
-COALESCING PREFILTER W/ AUTO DRAIN MUST BE INSTALLED
-DRYERS ARE DESIGNED FOR 100ºF INLET TEMPERATURE
-DRYER SHOULD BE LOCATED IN AN AREA ACCESSIBLE FOR MAINTENANCE
-AMBIENT TEMP. SHOULD BE BETWEEN 35ºF & 100ºF
-LOCATION SHOULD BE CLEAN, COOL, w/ A LEVEL, VIBRATION FREE FLOOR.
KEY:
AD = AUTOMATICDRAIN
F = PARTICULATEFILTER
C = COALESCINGFILTER
A = ADSORBINGFILTER
T = TEMPERATUREINDICATOR
D = DEWPOINT INDICATOR/CONTROLLER
= DIFFERENTIALPRESSUREINDICATOR
DWG AT718
Rev. C
1/15/92
NOTES:
1.By-Pass Piping should be installed around filters and dryer
for servicing.
2.Differential pressure indicators should be installed on filters
for monitoring of elements
3.Coalescing Prefilter & Particulate Afterfilter are required.
Particulate filter before dryer and adsorber after dryer are
optional.
4.Auto drains must be installed on separator, air receiver,
prefilter & coalescer.
5.Location of receiver may vary depending on particular
conditions & type of compressor. Auto drain required when
receiver is mounted upstream of dryer.
6.Locate coalescing filter as close to dryer as possible.

Pg. -15-
AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
16. B. Flow Diagram: TW10 & TW15

Pg. -16-
AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
16. C. Flow Diagram: TW25 & TW55

Pg. -17-
AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
16. D. Wiring Diagram, Standard Dryer

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AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
17. A.

Pg. -19-
AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
17. B. Purge Charts

Pg. -20-
AIRTEK 4087 WALDEN AVENUE, LANCASTER, NY 14086 Tel: [phone] Fax: [phone]
17 C. ANALYZING CHART
ANALYZING / PERFORMANCE CHART
TW10 -- TW55 HEATLESS TWIN TOWER DRYER
DATE: _______________ DRYER INLET FLOW (SCFM): ____________________
MODEL: _______________ DRYER INLET TEMPERATURE: ____________________
SERIAL NUMBER: _______________ PURGE SETTING: ____________________
AMBIENT TEMPERATURE: _______________ COMPRESSOR HP: ____________________
OPERATING PRESSURE: _______________ CYCLE SWITCH SETTING: STND 10 MIN
SHORT 5 MIN
PERFORM EACH OF THE FOLLOWING CHECKS ONCE DURING LEFT TOWER DRYING & ONCE DURING RIGHT TOWER DRYING:
IS THERE ANY “BACK PRESSURE” IN THE REGENERATING TOWER? Y / N _______________ PSIG
WITH THE PURGE VALVE FULLY CLOSED, IS THERE ANY FLOW FROM THE EXHAUST VALVE? L: Y / N R: Y / N
HAVE YOU CHECKED THE CONDITION OF YOUR COALESCING PREFILTER ELEMENT?
HAVE YOU CHECKED THE AUTO DRAINS ON YOUR SEPARATOR, RECEIVER & PREFILTER TO ENSURE PROPER DRAINAGE?
STATUS LIGHTS (“X” WHEN LIT)
PRESSURE (PSIG) DRYING REGENERATING DEW
LEFT PURGE RIGHT REPRES POINT
TIME TOWER GAUGE TOWER LEFT RIGHT LEFT RIGHT (Optional)
1 MIN
2 MIN
3 MIN
4 MIN
5 MIN
6 MIN
7 MIN
8 MIN
9 MIN
10 MIN
11 MIN
12 MIN
13 MIN
14 MIN
15 MIN
16 MIN
17 MIN
18 MIN
19 MIN
20 MIN