AirTek SC Series User manual

SMART CYCLE
COLD TRAP
REFRIGERATED
AIRDRYERS
OPERATORS MANUAL:
MODELS SC/CT 40 to 3000
Service Department
1-800-451-6023
MAN-SCCT
PRICE $10.00

DearCustomer,
Let us take this opportunity to introduce our company.
Airtekis aninnovative manufacturerof industrialrefrigeration andfiltration equipmentfor
compressed air systems. Our product line includes after coolers, fluid coolers, water
separators,air filters, gas dryers, refrigerated air dryers and heatlessand heatreactivated
desiccant air dryers. Our products have found locations in all corners of the world.
We are committed to assuring your satisfaction with your new dryer. In doing so we have
developeda factoryauthorized networkof servicefacilities acrossthe countryand Canada.
This will aid in expedient service to you.
The most important step for you as a customer is to call us first if you are experiencing a
problemwithyourdryer.
Ifthere isa questionregarding anyor allof ourwarranty policiesand procedures,please
call. We can be reached at 1-800-451-6023, we would be happy to speak with you.
Thank You
ServiceDepartment
DRYERSPECIFICATIONDATA
ModelNo. OPTIONS:
SerialNo.
Max PSI
InletMaxTemperature
Capacity
Volt Phase
HZ
FLA
Max Fuse

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TABLE OFCONTENTS
1. Pre-Installation......................... 5
A. Inspection, Handling and Setup
B. Cautions and Operating Warnings
2. Dryer Installation...................... 5
A. Location of Dryer
B. AirlinePlumbing
C. Water Line Piping (Water Cooled Units)
D. Electrical Connections
E. Dryer Startup Instructions
3. Principle of Operation.......... 5 - 7
A. Air System
B. Refrigeration System
C. Panel Diagram
D. Operation
4. Adjustable Controls............... 8 - 9
A. Air Cooled Condenser
B. Adjustments of Controls
C. Separator Drains
5. Start Up Procedure.............. 9 - 10
A. Operational Instructions
B. Valve Schematics
6. Routine Maintenance
and Service............................. 11
7. For The Refrigeration
Service Technician..............11 - 12
A. Refrigerant, Oil and Dryers
B. Evaporator Leaks
C. Refrigerant Control Valves
D. Drains
E. Electronic Controls
F. Factory Assistance
8. Miscellaneous Dryer Data......... 13
A. Capacity Correction Factors
9. Dryer information Charts
and Electrical Schematics.. 14 - 29
A. Electrical Schematics
B. Flow Schematic
10. Diagnostic Codes................ 30 - 35
11. InstructionsFor
Ordering Parts......................... 35
12. Replacing Coalescer
Elements................................. 35
A. Refrigerated Gas Dryer Parts List
13. Metric Conversion Chart.............36
14. Warranty.............................. 37-41
A. General Conditions
B. Exclusions
C. Registration Card
D. Procedure
E. Service
F. Return of Defective Material

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1. PRE-INSTALLATION
Inspection, Handling and Setup
Inspect the dryer carefully upon arrival and note any
damage on the freight bill. File a notice of concealed
damage if: (1) there are any dents in the cabinet; (2) the air
and drain pipes are not straight; (3) there is any sign of oil
on the skid floor. File these claims with the carrier
immediately!
Cautions and Operating Warnings
* Never work on unit under air pressure.
* Never work on unit when power is connected.
* Do not over pressurize unit.
* Install unit in a clean, cool (50º - 85º F); well lighted
location.
* Do not shut unit off at disconnect switch except during
servicing. Unit must be turned on and off by the panel
switch located on the dryer.
* Do not pass air through the dryer while the dryer is in
the “OFF” position.
* Do not operate dryer at abnormal conditions (high flow,
high inlet temperature, high ambient, high inlet
pressure, etc.)
2. DRYERINSTALLATION
Location of Dryer
Unless supplied for special conditions, the air cooled
dryers must be located in an area with an ambient tem-
perature between 50º and 100º F., and free from explosive
and corrosive fumes. High ambient temperatures affect the
outlet dew point of the dryer. For every 10º F of ambient
temperature over 100º F, a decrease of 6% of dryer perfor-
mance is encountered with air cooled dryers. The unit
must not operate in an ambient of over 100º F. For ambient
conditions of over 100º F, water cooled dryers are sug-
gested and are available upon request.
CAUTION – Three feet of space must be allowed between
all open grills and walls or other objects. If the dryer is
installed in a confined area, an exhaust system must be
provided to avoid excessive recirculation of hot room air.
Airline Plumbing
All connections are made to the outside of the cabinet as
follows:
* Plumbing must be supported independently of the
dryer.
* If vibration is present, flexible metal hoses must be
installed to prevent it from being transmitted to the
dryer.
* Use unions or flange joints.
* Bypass piping around the dryer is recommended for
ease in servicing or removal of unit if necessary.
* Direction of flow through the dryer must be observed. A
check valve on the outlet of the dryer to prevent back
flow and false loading is recommended.
NOTE: Use two wrenches when connecting to dryer piping
so as to prevent damage to internal air or water lines.
Water Line Piping (Water Cooled Units)
On water cooled units, install a strainer ahead of the water
inlet. Dryers are designed for 85º F inlet water tempera-
ture. Higher water temperature reduces dryer capacity.
Minimum water pressure is 25 psi. Maximum water
pressure is 105 psi.
Electrical Connections
Before connecting electrical power to the dryer if appli-
cable (SC/CT40 to 100 have a standard power cord):
* Check for correct voltage and phase at electrical
connection box.
* Install a fused disconnect switch near the dryer.
* Connect power to the stripped leads located in the
electrical connection box or to main lugs of contactor,
whichever is necessary.
(NOTE: All units must be externally grounded to protect
against the possibility of severe electrical shock.)
*CAUTION: Wire the dryer separately from the air
compressor. The dryer must NOT cycle on and off
with the air compressor.
* Phase rotation is only important if the dryer has a 3
phase condenser fan. Fans must PULL air through
the condenser coil.
* Crankcase heaters are pre-wired at the factory to the
line side of the terminal box or contractor. Heaters
must be energized at all times, therefore the main
disconnect must be left on except when servicing the
dryer.
3. PRINCIPLE OFOPERATION
TheAIRTEK REFRIGERATED AIR DRYER is designed to
operate automatically and continuously from no load to full
load without freeze up.
Air System
The major air system components are the air to air
PRECOOLER / REHEATER, the EVAPORATOR, and the
MECHANICALSEPARATOR.
Hot, wet air enters the inlet of the precooler/reheater
where it is cooled by the outgoing air. The air then enters
the evaporator where it is cooled by the refrigerant causing
the air’s humidity to condense into liquid water.
Next the air travels to the separator/coalescer (Note: SC
systems do not have a coalescer). First, the air enters the
separator where bulk oil and moisture are removed from
the air stream through a combination of centrifugal action
and velocity reduction. Then the air enters the coalescer
element where the remaining oil and moisture mists are
removed. After removal from the air stream, all contami-
nants are ejected from the air system by automatic
solenoid or float drains.
From the separator/coalescer, the cold dry air enters the
outgoing side of the precooler/reheater where it is
reheated by the hot incoming air.
The precooler/reheater serves a triple purpose. By
precooling the incoming air, it conserves refrigeration use
and by reheating the outgoing air, it serves to eliminate

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sweating of pipes in the plant air system. Most important,
it increases the temperature dew point split, preventing
moisture from condensing out of the compressed air
when the air is expanded.
Refrigeration System
The major components of this system are the COMPRES-
SOR, the CONDENSER, and the EVAPORATOR. The
compressor pumps high pressure, high temperature
refrigerant to the condenser. The heat is dissipated
through finned tubes with the assistance of motor driven
fans. On water cooled units the heat is dissipated through
a water filled tube and shell condenser.
During the cooling process, the refrigerant changes from a
heat laden vapor to a liquid. This liquid refrigerant flows
from the condenser to the filter dryer, and then through the
sight glass which indicates refrigerant level. Immediately
before the inlet of the evaporator is a thermostatic expan-
sion valve which regulates the refrigerant flow to the
evaporator as low pressure cold liquid. The cold refrigerant
cools the air in the air system side of the evaporator. As the
low pressure liquid refrigerant absorbs the heat from the
air it boils and changes to a vapor. This low pressure, low
temperature vapor is then returned to the refrigerant
compressor where it is again compressed to a high
pressure, high temperature refrigerant, and the refrigera-
tion cycle repeats itself.
AIRTEK Dryers are rated to deliver full capacity (SCFM at
35ºF pressure dew point air) at 100 PSI line pressure,
receiving 100º F. water saturated inlet air, in 50 to 100º F
ambient, at 2 to 4 PSI pressure drop. Higher line pres-
sures, up to rated maximum. (higher pressure ratings are
available upon request), and cooler inlet air increases
capacity. Free liquid water, low pressures, higher air
temperatures and condensable chemical vapors, decrease
capacity. Correction figures for varying ambient tempera-
tures, heat load, and pressure ratings are located in this
manual. They can be found in the Capacity Correction
Factors, Page 12.
Smart Cycle / Cold Trap Dual Mode Operation
Smart Cycle and Cold Trap dryers are equipped with
Airtek’s patented Smart Cycle Dual Mode Demand Control-
ler. It has a mounted digital dew point readout that displays
the actual dew point temperature of the compressed air.
The drain is timed and adjustable to the customers needs
or is governed by a float, demand drain.
Dual Mode
Airtek Dual Mode cycling refrigerated air dryers can operate
in either of two energy saving modes.
Load/NoLoad Mode /Non-Cycling Demand
The Load/No Load mode is usually selected for normal
operation. When operating in the Load /No Load mode, the
refrigeration compressor cycles from a loaded condition to
an unloaded condition. The condition is determined by the
temperature of the compressed air flowing over a special,
patented temperature probe. The probe is located in the
compressed air discharge of the evaporator. When the
temperature of the compressed air falls to a degree below
the set point, the controller signals the unloader valve to
open. The compressor will continue to run but it will be
running in an unloaded condition. Its energy consumption
drops off to about 50%. When the temperature of the
compressed air rises to degree above the set point, the
Smart Cycle controller signals the unloader valve to close.
The compressor resumes full load operation.
Thermal Banking / Cycling
When operating in the Thermal Bank mode the refrigera-
tion compressor turns ON or OFF in response to the
temperature of the compressed air exiting the evaporator.
When the temperature of the compressed air falls to 30º F
or a degree below the set point for two minutes which ever
comes first, the sequence generates a Thermal Bank of
cold storage in the evaporator. When the compressed air
temperature rises to four degrees above the set point, the
refrigeration compressor turns back ON. The refrigerant
compressor restarts in an unloaded condition. Load is
introduced after a short time delay that allows the motor to
get up to speed. The combination of an unloaded start and
generous thermal storage prolongs compressor life while
delivering maximum performance and energy savings.
This mode is recommended for air loads at 50% or less.
4. ADJUSTABLECONTROLS
Separator / Coalescer Drains
All controls are preset at the factory for proper operation,
however you may need to make slight adjustments to the
following:
DEW POINT CONTROLLER: Thesetpoint of thecontroller
is the dew point achieved by the dryer. To raise or lower the
dew point, change the set point of the controller. The
middle and upper set points which are in 2º increments of
the lower set point adjust with the lower set point accord-
ingly.
DRAINCONTROLOPERATION: The“DRAINTEST”buton
when pressed will operate the Drain Relay (K1). The
“DRAIN OPEN” LED will illuminate indicating the drain valve
is open when the K1 drain relay is operated (see DRAIN
CONTROLSETTING.)
PANEL “C”: This is an optional panel that displays the
ambient air and inlet gas temperatures. The display
functions as a monitor only and to alarm if above the set
point. This alarm will NOT shut down the dryer. The alarm
settings are typically at 100º F. If you choose to raise or
lower this point, you can do so by pressing the set button,
setting the alarm point and pressing set again to read
actual temperature.
NOTE: The Dew Point Controller should never be below 32º
F for long periods of time. This could result in water
freezing in the evaporator tubes which could damage the
dryer, raise the dew point and cause pressure drops
throughout the dryer. The factory setting is 36º F. Although
the dew point may be set higher, very little power savings will
be realized from a higher setting.

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DISPLAYSandALARMS
1) DEWPOINTCONTROLLERANDDISPLAY. Directly
controls dew point and provides constant digital
display of dew point. Factory set at 36ºF. During
ACTUAL display mode, displays the dew point tem-
perature from 20º to 99º F or -6º to 37º C. During DP
SET mode, the unit displays dew point set points from
34º to 50ºF in 1º steps, or 1º to 10ºC in 1/2 steps. (Note
that the ones digit decimal point is used to indicate 1/
2º when displaying set point in Celsius scale.) ºC LED-
indicates that the temperature is displayed in Celsius.
ºF LED – indicates that the temperature is displayed in
Fahrenheit. ACTUAL LED – indicates the display is in
ACTUAL mode. Display shows actual temperature
being measured by system. DP SET LED - Indicates
that the display is in programming mode during which
the set point can be changed and stored. The dew
point display also displays the unit error codes when
they occur. (see Diagnostic codes)
2) ON/OFFBUTTONFORLOAD/NOLOADMODE. LOAD/
NO LOAD LED - Indicates when the unit is operating in
the Load/No Load mode.
3) ON/OFFBUTTONFORTHERMALBANK MODE.THER-
MAL BANK LED - Indicates when the unit is operating
in the thermal bank mode.
4) RAISE and LOWER BUTTONS. These areusedto
adjust the set point values. The set point will change
once for each time pressed. If the button is pressed
and held, the set point will change one step per
second.
5) SET BUTTON. Toggles between Actual Display mode
and Set point Display mode. During the Set point
Display mode, the Raise and Lower keys are used to
select new set points which are stored in nonvolatile
memory when the mode is set back to ACTUAL. If no
keys are pressed within 15 seconds, the mode is
automatically set to “ACTUAL”. This switch is also
used to select the temperature scale that the unit will
operate in. By pressing and holding for 5 seconds the
unit will toggle between the Fahrenheit and Celsius
scale.
6) HIDDEN BUTTON. Positioned in the bottom center of
the Dew Point window between the MODE keys. When
pressed, the display will show the external suction
temperature at the expansion bulb. It has no further
effect on operation. It may also be used for other
diagnostics and factory test purposes
7) POWER SAVER ACTIVE LED.Unitin mode oflow
power consumption. Refrigeration system unloaded
or in thermal banking condition.
8) HIGH DEW POINT ALARM LED. Indicatesthatthe unitis
in the High Dew Point condition. The high dew point
alarm light, with remote dry contacts, will activate when
the actual dew point is 15º F higher than the dew point
set point. Any diagnostic code will activate the high
dew point alarm immediately.
9) DRAIN CONTROL SETTINGS. TheDP5050-L series
control panel will operate by either a ‘LEVEL FLOAT’ or
‘TIMED’ interval. If the dryer is equipped with a Level
Float (electrical connections to terminal J9), the drain
will respond to the float signal on demand to operate
the drain. The duration that the drain valve is open, will
be the amount of time it takes for the fluid level to drop
and reset the float signal, plus, a pre-set time of a few
seconds thereafter. The drain valve will also operate
automatically once every 30 minutes (independent to
the float signal). The 30 minute timed interval setting
can be adjusted down to 1 minute or raised up to 60
minutes if desired. To adjust the drain ‘Timed Interval’
setting, press the SET button twice (note that the Actual
and DP Set LED’s will both extinguish). The value
indicated in the display will be the Timed Interval
setting. Use the UP or DOWN arrow to the desired
timing set point. Pressing the SET button again will
return the display to reading the dew point and the
‘Actual’ LED will once again illuminate.
10) DRAIN OPEN LED. Indicates that the drain valve is
open.
11) AIR INLETand AIROUTLET PSIGAUGES.Indicatesthat
unit is pressurized. Unit must be depressurized and
bypassed before any service work is done on air
system. Excessive pressure drop (more than 5 PSIG)
across dryer indicates water may be freezing in the
evaporator.
12) HIGHAMBIENTTEMPERATUREDISPLAYANDLIGHT.
Should not be above 100ºF. High ambient temperature
can cause head pressure tripping of refrigeration
system and could result in non-warranty damage to
refrigeration compressor. Be sure dryer is installed
properly with adequate ventilation for air cooled units.
This display is used for water temperature in
watercooled units.
13) HIGHINLETTEMPERATUREDISPLAYANDLIGHT.
Should not be above 100ºF. High inlet air temperature
can cause overloading of dryer. If lit, check com-
pressed air aftercooler and/or oil cooler on air com-
pressor.
14) HIGHCOALESCER PSIDLIGHT (CTONLY). Pressure
drop across coalescer element is too high. Should not
be above 9 PSIG. Excessive pressure drop could
cause mechanical failure of element resulting in flood
of oil, water and contaminants downstream of dryer.
Change element when necessary.
EXTERNALSENSORS, CONTROLS and RELAYS
DRAIN RELAY (K1) – This onboard relay opens the drain
valve according to drain controls.
SUCTION RELAY (K2) – This onboard relay turns on
according to the mode and dew point conditions and opens
the suction or liquid line valve when active.
UNLOADER RELAY (K3) –This onboard relay turns on
according to the mode and dew point conditions and opens
the unloader valve when active.

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COMPRESSOR RELAY (K4) – This onboard relay controls
the compressor according to the mode and dew point
conditions.
HIGH DEW POINT RELAY (K5) –Thisonboardrelay and
LED alarm turns on when the dew point is 15º F above the
set point. This is also active during any error conditions.
COMPRESSORUNLOADER #1RELAY(CU1)(FU Panel
ONLY) – This onboard relay turns on when the dew point is
below the setpoint +2ºF and turns off when the dew point is
above the setpoint +2ºF.
COMPRESSORUNLOADER #2RELAY(CU2)(FU Panel
ONLY) – This onboard relay turns on when the dew point is
below the setpoint +4ºF and turns off when the dew point is
above the setpoint +4ºF.
DEW POINT SENSOR (Probe 1) – Resistive NTC sensor for
measuring dew point temperature.
SUCTIONTEMPERATURE SENSOR(Probe 2) –Resistive
NTC sensor for measuring external suction temperature at
the expansion bulb (E3 Probe).
5a. START UP FOR MODELS SC/CT 40 - 250
NOTE: Please read and understand the entire operation
and maintenance manual prior to starting the dryer. This is
a brief start up procedure for those familiar with dryer
operation.
CAUTION: There should be no air flow through the dryer
before or during start up. It is recommended that the dryer
be installed with bypass piping to better service the unit.
DRYERSTARTUPPROCEDURE:
1) Make main electrical connection to dryer and apply
power. Refer to dryer name plate or manual to
determine correct voltage.
• On models SC/CT 40 to 100 proceed.
• On models SC/CT 130 to 165 leave power on for 8
hours before proceeding to step 5
• On models SC/CT 220 to 250 leave power on for 8
hours before proceeding.
2) On water cooled units make sure there is proper water
pressure and temperature supplied to the water
condenser. (Min 25 psi and max 85º F water tempera-
ture)
3) On models SC/CT 220 to 250 - Remove lid from dryer.
4) On models SC/CT 220 to 250 dryers are shipped with
TAGGED refrigeration servicevalvesclosed. TAGGED
service valves must not be opened until main power is
permanently applied. However, ONLY TAGGED service
valves must be opened prior to start up.
* LocateTAGGED service valves.
* Remove protective cap from valve stem. (see figure
below)
* Using a refrigeration service wrench or small
crescent wrench, turn the valve stem counterclock-
wise until it stops. Occasionally it may be necessary
to retighten the packing nut (clockwise) if a leak is
observed. The valve will now be fully open.
* Replace cap.
5) Turn dryer on at the control panel by pushing one of the
mode selection buttons. (SC/CT 220 to 250 should be
turned on immediately after TAGGED valves are
opened.) If storage conditions were adverse, the
refrigerant compressor may make a loud metallic
hammering noise. If this happens, turn the dryer off at
the control panel, wait half a minute and turn it on
again. repeat this until the refrigerant compressor
runs smoothly. The digital dew point display should
start dropping to 35ºF.
6) With the dryer turned ON from the control panel and
cycling several times, you may now introduce com-
pressed air to the dryer. Open the inlet and outlet
isolation valves. Close the bypass valve.
7) Check automatic drain for proper operation. Drain
should open at regular intervals based on the drain
control settings or water level. Clean Y-strainer after
the first 8 hours of operation. (If unit has float, demand
drains there are no Y-strainers.)
8) Restart dryer using this procedure after maintenance,
power failure or after prolonged shutdown periods.
CAUTION: Failure to follow the above steps in the order
shown MAY result in damage to equipment NOT covered
under warranty.
Operating Instructions:
Always:
* Turn dryer ON and OFF with control panel button.
Keep power to unit during off cycles.
* Start dryer and allow it to cycle several times prior
to allowing air flow through the dryer.
* Clean condenser when dirty.
* Keep ambient temperature under 100º F.
* Keep inlet temperature under 100º F.
* Keep inlet pressure within design limits.
* Check and clean Y-strainer periodically. (if appli-
cable)
Never:
* Turn off main power disconnect except when
servicing.
* Allow air to flow through the dryer when it is not
running.
* Cycle dryer with air compressor.

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5a. START UP FOR MODELS SC/CT 330 and UP.
NOTE: Please read and understand the entire operation and
maintenance manual prior to starting the dryer. This is a brief
start up procedure for those familiar with dryer operation.
CAUTION: There should be no air flow through the dryer
before or during start up. It is recommended that the dryer be
installed with bypass piping to better service the unit.
DRYERSTARTUPPROCEDURE:
1) Make main electrical connection to dryer and apply
power. Refer to dryer name plate or manual to determine
correct voltage. Leave power on unit for 8 hours before
proceeding.
2) On water cooled units make sure there is proper water
pressure and temperature supplied to the water con-
denser. (Min 25 psi and max 85º F water temperature)
3) Remove front cover, if necessary, to expose refrigeration
service valves.
4) Dryers are shipped with TAGGED refrigeration service
valves closed. TAGGED service valves must not be
opened until main power is permanently applied.
However, ONLY TAGGED service valves must be opened
prior to start up.
* Locate TAGGED servicevalves.
* Remove protective cap from valve stem. (see figure
below)
* Using a refrigeration service wrench or small crescent
wrench, turn the valve stem counterclockwise until it
stops. Occasionally it may be necessary to retighten
the packing nut (clockwise) if a leak is observed. The
valve will now be fully open.
* Replace cap.
* In case of refrigeration ball valves, you must turn 90
degrees to open as stated on valve. (See figure below).
5) On models SC/CT 1500 and up, locate the compressor
service toggle switch. This service switch must be
turned on immediately after valves are opened.
* On Models SC/CT 1500 and up, the refrigeration
compressor may run briefly and then stop. This
process is called pump down. If storage conditions
were adverse, the compressor may make a loud
metallic hammering noise. If this happens, turn the
service switch off and wait half a minute, then back on.
Repeat this step until the compressor runs smoothly,
then stops. Leave the service switch in the ON
position.
6) The dryer is now ready to run. Turn the dryer on at the
control panel (load/No Load Mode).
The digital display should start dropping to 35ºF.
7) With the dryer turned ON from the control panel and
cycling several times, you may now introduce com-
pressed air to the dryer. Open the inlet and outlet
ISOLATION VALVES. Closethe BYPASSVALVE.
8) Check automatic drain for proper operation. Drain
should open at regular intervals based on the drain
control settings. Clean Y-strainer after the first 8 hours
of operation.
9) Restart dryer using this procedure after maintenance,
power failure or after prolonged shutdown periods.
CAUTION: Failure to follow the above steps in the order shown
MAY result in damage to equipment NOT covered under
warranty.
Operating Instructions:
Always:
* Turn dryer ON and OFF with control panel button. Keep
power to unit during off cycles.
* Start dryer and allow it to cycle several times prior to
allowing air flow through the dryer.
* Clean condenser when dirty.
* Keep ambient temperature under 100º F.
* Keep inlet temperature under 100º F.
* Keep inlet pressure within design limits.
* Check and clean Y-strainer periodically. (if applicable)
Never:
* Turn off main power disconnect except when servicing.
* Allow air to flow through the dryer when it is not running.
* Cycle dryer with air compressor.

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6. ROUTINEMAINTENANCEANDSERVICE
Air Cooled Condenser
Very little routine care is necessary for the Airtek Dryer. The
most important step for an air cooled dryer is to keep the air
cooled condenser clean. The air is being taken in across
the condenser. Dirt from the ambient air will accumulate on
the finned tubes of the condenser coil. As the dirt will
accumulate on the rear of the condenser, blowing from the
inside out is most effective. In dusty areas the simple
inexpensive installation of a furnace filter will stop the
majority of dirt entering the dryer’s condenser. This should
be changed when visibly dirty. If the condenser does
become dirty, an abnormally high refrigeration discharge
pressure will occur. The unit may shut down on high dew
point or high pressure. This will greatly reduce the life of
the refrigeration compressor and could lead to a voiding of
the warranty.
Separator/Coalescer Drains
Drains should be checked regularly. Failure of an auto-
matic drain can result in extreme amounts of water and
debris in your air system.
7. FORTHE REFRIGERATION SERVICE
TECHNICIAN
Airtek recommends that only qualified and experienced
refrigeration mechanics do repair work on these units.
This section is a list of hints and instructions for the skilled
serviceman and relating specifically to the Airtek Smart
Cycle and Cold Trap refrigeration systems.
Recharging Dryer – Refrigerant, Oil and Dryers
Refer to the dryer information tag on the front of the unit for
the approximate charge needed for each unit. The relatively
large charge is needed because of the flooded-shell
evaporators. Use the following to assess the adequacy of
the charge when unsure:
* Because of the widely fluctuating pressures occurring
when the Smart Cycle or Cold Trap system unloads, it
is impractical to use pressures or sightglass indica-
tions to determine correct charge. Gross undercharge
results in a hot suction line and overheated compres-
sor. Gross overcharge is indicated if the head and
suction pressure rises greatly when the unit is loaded.
Remember to clean the condenser before deciding on
the charge.
* The sightglass should stay filled most of the time
when the dryer has its customary air load. It is normal
for the glass to break up when the condenser fan
starts if the load is light or when the unit unloads. It
may take time to refill when it reloads. Don’t charge to
clear the glass with no load; that will be too much.
* All units have a charging fitting on the evaporator shell.
The unit must be charged through this fitting and/or the
liquid line service valve. The best way is to dump liquid
into both ports with the dryer off, then start up and
continue feeding a full stream of liquid into the evapo-
rator until charged.
Do not charge vapor. You want the charge installed as fast
as possible so the oil will be returned.
Additional oil is added at the factory to compensate for the
migration with the freon. If a compressor is replaced,
remove the drain plug from the evaporator shell to drain any
excess oil trapped. If that isn’t possible, it may be neces-
sary to remove oil from the system after start-up. Excess oil
is indicated by noisy and vibrating compressor operation. If
a replacement evaporator is installed, oil should be added.
Prolonged operation with insufficient charge or a bad TXV
may cause oil to be trapped in the evaporator. If the
compressor is still good, this oil will return within a few
minutes of operation with the correct conditions. For R-22
applications use 150w refrigeration mineral oil, For R-134A
and R-404A, applications use synthetic refrigeration oil.
Replace both suction and liquid filter-dryers together
whenever the system has been exposed to air or water,
unless it’s brand new or you know how much air has gone
through it. Solids will be caught in the suction drier even if
the system is dry.
NOTE: Magnum models do not have enough receiver
capacity to hold the whole charge. A complaint of pressure
tripping only on start-up is usually due to air through the
dryer when it is shut down or low cooling pressure rather
than overcharge. This causes refrigerant to migrate
backwards from the evaporator and overfill the high side of
the system.
Evaporator Leaks
If there is a leak between the tube and shell side of the
evaporator, the usual symptom is high head pressure,
because the air pressure is higher than the refrigerant
pressure.
To determine this, bypass air flow, stop dryer, and observe
head pressure after it stabilizes. 20 minutes is sufficient. If
the pressure is much higher than that corresponding to the
ambient temperature, there is air in the system. Purge air
at compressor discharge or receiver inlet to verify.
Gross leak-checking of the evaporator is done at the
separator drain with air pressure off and at least an hour
wait. If a leak is verified, it can often be fixed by removing
the bonnets, locating the leak with bubble soap and re-
rolling the leaky tubes. Split evaporator tubes can be
plugged with special tapered brass plugs.
WARNING: If the refrigerant has been seriously contami-
nated with water, you probably won’t be able to dry it with
dryers and certainly not vacuum. Best to do solvent
cleanup on the evaporator and suction accumulator or
replace the evaporator. A flooded shell holds a lot of water
and is difficult to clean effectively.
Refrigerant Control Valves
Expansion valves: The superheat (+15º F) that the valve
controls is created in the control evaporator or suction line
heat exchanger. There is liquid or zero superheat at the
main evaporator outlet to facilitate oil return and keep the
shell flooded. If there is superheat at the main evaporator
outlet or if the suction line to the compressor is warm to the
hand, 1) check the charge. If the sightglass is full, 2) the
TXV may be defective or the liquid line is blocked. The TXV
superheat adjustment is not critical.

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12
Airtek uses standard type valves that can be found in
wholesale houses anywhere. When replacing or repairing
them, remember these points:
* Don’t use any TCLEAlco valves. TCLE valves are too
slow.
* Use cross-ambient “C” or liquid “L” charges. Do not
use any pressure limiting or all-purpose “W” charges.
* We recommend that you increase the superheat
setting of the new valve about 5º F from the factory
setting. Turning the stem 2 turns in is about right.
* Position the sensing bulb of the new valve just where
the old one was. It is crucial that the suction line be
clean and the bulb well insulated.
Solenoid Valves: The suction solenoid valve rarely causes
any trouble because the pressure difference across it is
never great. Unloader solenoids operate with greater
differentials and so are more likely to fail. Airtek uses
valves with a rated life of more than two million operations.
When they finally wear out, the usual symptom is failure to
close. The valves can usually be restored by installing a
diaphragm repair kit available from Airtek or the valve’s
local distributor.
Drains
The draining of water from the separator is the most crucial
part of the whole process. A complaint of “There’s more
water in the air now than there was before the dryer was
installed” is usually a drain problem.
Airtek has a demand operated drain. Operate the drain
manually, push to test. Check the float switch, board or
solenoid valve if not.
Electronic Controls
A dew point temperature controller is used on the Smart
Cycle Dryers. The controller operates the unloader
solenoid, opening it to stop refrigeration if the sensed
temperature goes below the controller setting, usually 36ºF.
The suction solenoid is closed during unloading.
This temperature is sensed by a sensing probe inserted in
one of the evaporator tubes. When air passes over the
probe, the air temperature controls the dew point normally.
When there is little or no air flow, the controller sees the
evaporator temperature, and is able to prevent it from going
below freezing.
The operation of the dew point controller is really simple.
All it does is switch back and forth between opening the
suction line solenoid and closing the unloader and vice
versa. A malfunction of the control system can be sus-
pected if:
1) The suction pressure won’t fall when the dew point is
above the set point. You can suspect the unloader
solenoid isn’t closing due to a bad diaphragm.
2) The suction pressure won’t rise when the dew point
goes below the set point and the controller switches, in
load/unload mode. If the pressure falls rapidly when
the controller switches to “power saver” mode the
unloader solenoid isn’t opening. If controller switch
doesn’t seem to do anything it has to be the controller
or wiring.
3) Suction pressure is very low even when controller
reads over the set point or unit appears to be pumped
down and stopped when it shouldn’t be. One or both
solenoids isn’t opening when it should.
4) Water freezes in the evaporator causing air pressure
drop (dew point set 34 or higher). This can be partial
failure of unloader solenoid to open, indicated by more
than 60 PSI difference between compressor suction
and discharge.
5) There is erratic or out-of-range indication of dew point.
This is controller or sensor trouble. Consult factory for
details.
6) Dryer won’t restart after you stopped it for a test. This
is normal if you stopped when it was unloaded (load-
unload mode) or shut down (start-stop mode). It will
restart when the dew point temperature comes above
the controller setting.
NOTE: For a complete troubleshooting guide, see pages
30-35.
Remember that the easiest way to distinguish between
control and solenoid malfunction is to hold a steel object,
like a pocket screw driver, over the top of the valve’s
enclosing tube that sticks out from the coil and feel for
magnification. The magnification means the valve is
energized. If you don’t feel it, remember to look at the coil
before suspecting the controller.
The two displays marked AMBIENT or WATER and AIR IN
indicate those temperatures and control only the respective
alarm lights (see ADJUSTMENTS). It is an alarm only and
will not shut your unit down.
Factory Assistance
Please do not hesitate to call the Airtek factory for technical
information and assistance. We have skilled troubleshoot-
ing and engineering personnel who are thoroughly familiar
with the equipment. A short call may save a long trouble-
shooting experience. 1-800-451-6023.
Instructions for Ordering Parts
All parts orders should be placed with your Airtek Dealer.
Should you not know the dealer in your area, contact Airtek
at [phone].
When ordering parts, specify dryer model and serial
numbers to insure receiving proper parts (see nameplate
on unit).

Airtek 4087 Walden Avenue, Lancaster, NY 14086 TEL: [phone] FAX: [phone] E-MAIL: [email protected] WEB SITE: www.airtek.com
13
8. MISCELLANEOUSDRYER DATA
Capacity Correction Factory
All dryer ratings shown are at 100ºF inlet temperature,
100ºF ambient temperature, 100 PSIG inlet pressure. To
correct for different conditions, use Table A, B, C, and D.
Correction Formula:
New Capacity SCFM = (Cat. Rating SCFM) x (A) x (B) x (C) x
(D)
Example: What is the new rating for a Model 3000 at:
(A) Operating PSI of 100 PSIG
(B) Ambient Temperature of 90ºF.
(C) Inlet air temperature of 110ºF. and
(D) Dew point of 35 - 39ºF
Answer:
(SCFM) = 3000 x (1) x (1.05) x (.83) x 1 = 2614.5 SCFM
CTemp. ºF 80 90 100 110 120
Factor 1.5 1.22 1 .83 .69
Inlet Air Temperature Correction
PSI 50 75 100 125 150
Factor 0.8 0.9 1 1.02 1.05
D
B
A
Temp. ºF 90 100 110 --- ----
Factor 1.05 1 0.9 --- ---
Dew Point 35ºF - 39ºF 42ºF - 45ºF 50ºF
Factor 1 1.10 1.25
Ambient Air Temperature Correction
Inlet Air Pressure Correction
Dew Point Correction Factors

Airtek 4087 Walden Avenue, Lancaster, NY 14086 TEL: [phone] FAX: [phone] E-MAIL: [email protected] WEB SITE: www.airtek.com
14
9.DryerInformationCharts
* Approximate running amps 460 volt / 3 ph = 2.0 amps. x HP
* Approximate running amps 230 volt / 3 ph = 4.0 amps x HP. For exact RL amps check name plate
* Approximate locked rotor amps = 4 to 6 times running amps.
* Water Cooled Units - Max Water PSI = 105 PSI
Min Water PSI = 25 PSI
Max Water Temperature = 85ºF
NOTE:(1) “M/C” amps is minimum circuit ampacity valuedeveloped by UL,this value has a calculated safety value and
may be used for wire sizing.
*Pressures referenced in this section refer to units using R-22. For other refrigerants, please refer to service
tag for specifications.
NOTE: If you own a watercooled unit, the second last character in your model number will be a “W” (ie: SC/CT
1000-W4)
SC/CT40 0.33 7.1 115/1 6.8 20 20 3750 275 3 oz.
SC/CT60 0.5 9.5 115/1 13.5 20 20 7500 350 3 oz.
SC/CT80 0.5 9.9 115/1 13.5 20 20 7500 350 3 oz.
SC/CT 100 0.75 13.8 115/1 19.5 30 30 11250 800 3 oz.
SC/CT 130 0.75 14.0 115/1 19.6 30 30 11250 800 3 oz.
SC/CT 165 0.75 14.3 115/1 19.6 30 30 11250 800 3 oz.
SC/CT220-A2 1 7.3 230/1 8.7 20 15 15000 1050 3 oz.
SC/CT220-A4 1.5 3.8 460/3 6 15 15 22500 1125 3 oz.
SC/CT250-A2 1.5 10.36 230/1 15.9 20 15 22500 1125 3 oz.
SC/CT250-A4 1.5 3.9 460/3 6 20 15 22500 1125 3 oz.
SC/CT330-A2 1.5 10.36 230/1 15.9 20 20 22500 1125 8 oz.
SC/CT330-A4 1.5 3.3 460/3 6 15 15 22500 1125 8 oz.
SC/CT400-A2 2 13.4 230/1 19.1 30 30 30000 2000 15 oz.
SC/CT400-A3 2 8.48 230/3 13.2 20 20 300000 2000 15 oz.
SC/CT400-A4 2 4.24 460/3 6.8 15 15 300000 2000 15 oz.
SC/CT500-A3 3 13.4 230/3 23.7 30 30 45000 2300 15 oz.
SC/CT500-A4 3 6.7 460/3 11.6 20 20 45000 2300 15 oz.
SC/CT650-A3 3 13.4 230/3 23.7 30 30 45000 2300 15 oz.
SC/CT650-A4 3 6.7 460/3 11.6 20 20 45000 2300 15 oz.
SC/CT800-A3 4 17.9 230/3 25.9 30 30 60000 4200 18 oz.
SC/CT800-A4 4 10.6 460/3 13.2 30 30 60000 4200 18 oz.
SC/CT1000-A4 5 9.6 460/3 14.4 20 20 75000 5000 24 oz.
SC/CT1200-A4 5 9.8 460/3 14.4 20 20 75000 5000 24 oz.
SC/CT1500-A4 7.5 16.1 460/3 20.1 30 30 112500 5600 30 oz.
SC/CT2000-A4 10 19.1 460/3 20.1 30 40 150000 5850 45 oz.
SC/CT2500-A4 15 23.9 460/3 38.4 40 60 225000 12900 45 oz.
SC/CT3000-A4 15 24.1 460/3 38.4 40 60 225000 12900 69 oz.
(1) Max Heat
Ref. Volt “MC” Max Circuit Reject Fan Additional
ModelNo. HP FLA PH Amps Fuse Breaker BTU/HR CFM OilChange

Airtek 4087 Walden Avenue, Lancaster, NY 14086 TEL: [phone] FAX: [phone] E-MAIL: [email protected] WEB SITE: www.airtek.com
15
9.Dryer InformationCharts (Con’t)
SC/CT40 N/A N/A N/A 2 R-22 185 N/A 20 350 3/8” 1”
SC/CT60 0.36 0.54 0.9 2 R-22 185 N/A 20 350 3/8” 1”
SC/CT80 0.36 0.54 0.9 3 R-22 185 N/A 20 350 3/8” 1”
SC/CT 100 0.5 0.75 1.25 5 R-22 185 N/A 20 350 3/8” 1-1/2”
SC/CT 130 0.5 0.75 1.25 5 R-22 185 N/A 20 350 3/8” 1-1/2”
SC/CT 165 0.5 0.75 1.25 5 R-22 185 N/A 20 350 3/8” 1-1/2”
SC/CT220-A2 0.74 1.11 1.85 8 R-22 185 N/A 20 350 3/8” 2”
SC/CT220-A4 1.0 1.65 2.75 8 R-22 185 N/A 20 350 3/8” 2”
SC/CT250-A2 1.0 1.65 2.75 8 R-22 185 N/A 20 350 3/8” 2”
SC/CT250-A4 1.0 1.65 2.75 8 R-22 185 N/A 20 350 3/8” 2”
SC/CT330-A2 1.0 1.65 2.75 14 R-22 185 N/A 20 350 3/8” 2”
SC/CT330-A4 1.0 1.65 2.75 14 R-22 185 N/A 20 350 3/8” 2”
SC/CT400-A3 1.6 2.4 4.0 28 R-22 185 215 20 350 1/2” 2-1/2”
SC/CT400-A4 1.6 2.4 4.0 28 R-22 185 215 20 350 1/2” 2-1/2”
SC/CT400-A4 1.6 2.4 4.0 28 R-22 185 215 20 350 1/2” 2-1/2”
SC/CT500-A3 2.4 3.6 6.0 28 R-22 185 215 20 350 1/2” 2-1/2”
SC/CT500-A4 2.4 3.6 6.0 28 R-22 185 215 20 350 3/4” 2-1/2”
SC/CT650-A3 2.4 3.6 6.0 28 R-22 185 215 20 350 3/4” 2-1/2”
SC/CT650-A4 2.4 3.6 6.0 28 R-22 185 215 20 350 3/4” 2-1/2”
SC/CT800-A4 3.0 4.5 7.5 37 R-22 185 215 20 350 3/4” 2-1/2”
SC/CT800-A4 3.0 4.5 7.5 37 R-22 185 215 20 350 1” 3” FL
SC/CT1000-A4 4.0 6.0 10.0 37 R-22 185 215 20 350 1” 3” FL
SC/CT1200-A4 4.0 6.0 10.0 37 R-22 185 215 20 350 1-1/2” 3” FL
SC/CT1500-A4 5.0 7.8 13.0 65 R-22 185 215 20 350 1-1/2” 4” FL
SC/CT2000-A4 7.6 12.0 20.0 120 R-22 185 215 20 350 1-1/2” 6” FL
SC/CT2500-A4 10.0 16.0 26.0 120 R-22 185 215 20 350 1-1/2” 6” FL
SC/CT3000-A4 11.0 17.0 27.5 168 R-22 185 215 20 350 1-1/2” 6” FL
Water Water Water
Flow Flow Flow Freon Fan#1 Fan#2 Low High
GPM @ GPM @ GPM@ Change Freon set set PSI PSI Water Air
ModelNo. 60ºF 70ºF 90ºF Lbs Type (+/- 10 PSI) (+/- 10 PSI) Switch Switch In/Out In/Out

Airtek 4087 Walden Avenue, Lancaster, NY 14086 TEL: [phone] FAX: [phone] E-MAIL: [email protected] WEB SITE: www.airtek.com
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Airtek 4087 Walden Avenue, Lancaster, NY 14086 TEL: [phone] FAX: [phone] E-MAIL: [email protected] WEB SITE: www.airtek.com
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Airtek 4087 Walden Avenue, Lancaster, NY 14086 TEL: [phone] FAX: [phone] E-MAIL: [email protected] WEB SITE: www.airtek.com
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Airtek 4087 Walden Avenue, Lancaster, NY 14086 TEL: [phone] FAX: [phone] E-MAIL: [email protected] WEB SITE: www.airtek.com
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Airtek 4087 Walden Avenue, Lancaster, NY 14086 TEL: [phone] FAX: [phone] E-MAIL: [email protected] WEB SITE: www.airtek.com
20