Ingersoll-Rand EHD Series Assembly instructions

EHD275
EHD360
EHD500
EHD650
EHD820
EHD1000
EHD1225
EHD1500
EHD1700
EHD2000
EHD2300
EHD3300
English: 1-1
Español: 2-1
Before installation or starting the dryer for the
first time, study this manual carefully to obtain
a clear knowledge of the dryer and of the du-
ties to be performed while operating and main-
taining the dryer.
RETAIN THIS MANUAL WITH DRYER.
This technical manual contains IMPORTANT
SAFETY DATA and should be kept with the
dryer at all times.
Bulletin 355 Revision F (9/99)
©1999 Ingersoll-Rand Company
Printed in USA
EXTERNALLY HEATED
COMPRESSED AIR DRYERS
EHD SERIES
OPERATOR’S
INSTRUCTION MANUAL

TABLE OF CONTENTS
INTRODUCTION ..........................1-1
SAFETY ................................1-1
INSTALLATION...........................1-1
Receiving and Inspection ...................1-1
Handling ...........................1-2
Ambient Air Temperature ..................1-2
Location and Clearance ....................1-2
System Arrangement .....................1-2
Piping and Connections....................1-2
Desiccant ...........................1-3
Muffler ............................1-3
Electrical Connections ....................1-3
INSTRUMENTATION........................1-3
Switch Failure Alarm .....................1-4
Heater Temperature Alarm ..................1-4
High-Humidity Alarm (Optional)...............1-4
AIRSaver Control (Optional) .................1-4
Dew Point Monitor (Optional) ................1-4
Remote Alarm Contacts....................1-4
Moisture Indicator (Optional).................1-4
Vessel Temperature Gauges .................1-4
Vessel Pressure Gauges ....................1-4
OPERATION.............................1-4
How It Works .........................1-4
START-UP..............................1-6
PS Module Valve Setting ...................1-6
MAINTENANCE ...........................1-6
Shutdown ...........................1-6
Desiccant Dusting.......................1-7
Maintenance Schedule ....................1-7
DAILY.................................1-7
YEARLY ...............................1-7
Returns to Manufacturer ...................1-8
Desiccant Replacement ....................1-8
Purge Field Adjustment....................1-9
High-Humidity Alarm Field Adjustment ...........1-9
FIELD SERVICE GUIDE .....................1-10
EHD Sequence of Operation ................1-12
REPLACEMENTPARTS......................A-1
REFERENCE DRAWINGS.....................A-1

INTRODUCTION
EHD Series externally heated dryers use
nonconsumable desiccants to remove moisture from
compressed air to achieve pressure dew points as low as
–40°F. The dryer processes a continuous flow of air
through two desiccant vessels, one adsorbing moisture
from the inlet air while the other is being reactivated.
Reactivation is accomplished by diverting a portion of
the inlet process air through a venturi which also draws
ambient air into the purge line. This combination of in-
let process air and ambient air is then passed through a
heater. The heated air is used to regenerate the
offstream vessel. The drying cycle is controlled by a mi-
croprocessor.
To ensure continuing good dryer performance and safe
operation, everyone who installs, uses or maintains the
dryer must read and carefully follow the instructions in
this manual. Throughout the manual, the word dryer is
used to refer to EHD Series externally heated air dryers.
SAFETY
EHD Series dryers are designed and built with safety as
a prime consideration; industry-accepted safety factors
have been used in the design. Each dryer is checked at
the factory for safety and operation. The desiccant ves-
sels are hydrostatically tested to 1½ times the maximum
pressure in accordance with ASME code requirements.
Factory-installed safety relief valves are standard on
each dryer.
WARNING
The following safety rules must be observed to
ensure safe dryer operation. Failure to follow
these rules may void the warranty or result in
dryer damage or personal injury.
1. Never install or try to repair any dryer that has been
damaged in shipment. See the Receiving and In-
spection instructions in this manual for appropriate
action.
2. Never operate the dryer at pressures or temperatures
above the maximum conditions shown on the data
plate.
3. Always supply electrical power that is within the al-
lowable voltage range shown on the data plate.
4. Never dismantle or work on any component of the
dryer or compressed air system under pressure.
Vent internal air pressure to the atmosphere before
servicing.
5. Never perform electrical service on the dryer unless
the main power supply has been disconnected. Parts
of the control circuit may remain energized when
the power switch is turned off.
6. Use only genuine replacement parts from the manu-
facturer. The manufacturer bears no responsibility
for hazards caused by the use of unauthorized parts.
Safety instructions in this manual are boldfaced for em-
phasis. The signal words DANGER, WARNING and
CAUTION are used to indicate hazard seriousness lev-
els as follows:
DANGER—Immediate hazard which will result in se-
vere injury or death.
WARNING—Hazard or unsafe practice which could re-
sult in severe injury or death.
CAUTION—Hazard or unsafe practice which could re-
sult in minor injury or in product or property damage.
The dryer data plate, attached to the front of the electri-
cal control box, contains critical safety and identifica-
tion information. If the data plate is missing or defaced,
contact your local distributor for a replacement.
INSTALLATION
Receiving and Inspection
Immediately upon receipt of the dryer, thoroughly in-
spect for damage that may have occurred during ship-
ping. Since the dryer is shipped F.O.B. New Castle,
Delaware, the carrier is legally responsible for damage
incurred during shipping. Shipping damage is not cov-
ered by the dryer warranty.
If goods are received short or damaged, notify the car-
rier and insist on a notation of the loss on the face of the
bill of lading. Otherwise no claim can be enforced
against the carrier.
If concealed loss or damage is discovered, notify the
carrier at once and request an inspection. The carrier
will make an inspection and grant a concealed damage
notation. The carrier will not consider any claim for loss
or damage unless an inspection has been made. If you
give the carrier a clear receipt for goods that have been
damaged or lost in transit, you do so at your own risk
and expense.
If there is any damage, file a claim with the carrier, then
call your local distributor for further instructions.
EHD Series (Bulletin 355) 1-1

Handling
The dryer is designed to be moved by means of the
shipping skid or the base channels. Handle the dryer
with care and only with equipment capable of lifting the
load (Table 1).
Table 1
SPECIFICATIONS
Model Capacitya
(scfm)
Approx
Weight
(lbs)b
In/Out
Connec-
tions
(inches)
EHD275 275 1080 1½NPT
EHD360 360 1240 2 NPT
EHD500 500 1780 2 NPT
EHD650 650 2350 2 NPT
EHD820 820 3520 3 FLG
EHD1000 1000 4540 3 FLG
EHD1225 1225 5160 3 FLG
EHD1500 1500 5890 3 FLG
EHD1700 1700 6600 3 FLG
EHD2000 2000 7197 4 FLG
EHD2300 2300 7870 4 FLG
EHD3300 3300 9420 4 FLG
aCapacity at design conditions: 100°F inlet air temperature, 100 psig
inlet air pressure, 100°F inlet pressure dew point, 80°F ambient tem-
perature, 60°F ambient dew point. Maximum pressure drop across
dryer 5 psi.
bWeight includes desiccant.
Note: Maximum operating pressure 150 psig; minimum operating
pressure 60 psig. If operating pressure is outside the standard 90-
110 psig range, consult factory. Maximum inlet air temperature
120°F; minimum inlet air temperature 40°F.
Ambient Air Temperature
Locate the dryer under cover in an area where the ambi-
ent air temperature will remain between 35°F and
120°F. If ambient temperatures below 35°F cannot be
avoided, contact your local distributor.
Location and Clearance
Install the dryer on a level pad. The dryer is provided
with 916-inch diameter anchor bolt holes. Anchor the
dryer to the floor with four ½-inch diameter bolts with a
minimum 4-inch thread engagement. Allow 24 inches
clearance on all sides of the dryer for servicing. Provide
adequate clearance for prefilter element, afterfilter ele-
ment and heater element replacement. Provide protec-
tion for the dryer if it is installed where heavy vehicles
or similar portable equipment is likely to cause damage.
System Arrangement
Install the dryer downstream of an aftercooler, separator
and high efficiency oil-removing filter(s) so that the
dryer inlet air is between 40°F and 120°F and contains
no liquid water or oil. Liquid water and/or inlet air tem-
peratures above 100°F can reduce drying capacity. Con-
tact your local distributor for information on proper
dryer sizing at elevated inlet air temperatures.
Oil contaminates the desiccant, reducing drying effi-
ciency and desiccant life. A high efficiency oil-
removing filter(s) must be installed at the dryer inlet. A
particulate filter should be installed at the dryer outlet to
capture desiccant particles.
DANGER
This dryer must be fitted with a high efficiency
coalescing filter and liquid drainer that is
maintained properly. Failure to do so could
result in an in-line fire.
WARNING
The afterfilter, if installed, must be rated for
450°F.
Piping and Connections
All external piping must be supplied by the user unless
otherwise specified. Refer to Table 1 for connection
sizes. Inlet and outlet manual shutoff valves and a vent
valve are recommended so the dryer can be isolated and
depressurized for servicing. The connections and pipe
fittings must be rated for or exceed the maximum oper-
ating pressure given on the dryer nameplate and must be
in accordance with industry-wide codes. Be sure all pip-
ing is supported. Do not allow the weight of any piping
to bear on the dryer or filters. Piping should be the same
size as or larger than the dryer connections. Piping
smaller than the dryer connections will cause high pres-
sure drop and reduce drying capacity.
If the purge exhaust piping must be extended outside the
dryer area, the piping must be sized so that it will cause
no back pressure. BACK PRESSURE WILL CAUSE
DRYER MALFUNCTION. Consult the factory for
piping details if required.
Dryer bypass piping may be installed to allow uninter-
rupted airflow during servicing. If the downstream ap-
plication cannot tolerate unprocessed air for short
periods, install a second dryer in the bypass line.
1-2 EHD Series (Bulletin 355)

CAUTION
Do not hydrostatically test the piping with the
dryer in the system. The desiccant will be
damaged if saturated with water.
Desiccant
EHD Series dryers, which dry to a –40°F pdp, use acti-
vated alumina as the desiccant in the dryer vessels.
Models EHD275 through EHD650 are shipped with ac-
tivated alumina in the dryer vessels. Activated alumina
is shipped loose with all other standard models.
All desiccant shipped loose must be added to the
dryer vessels before the dryer is put into service.
Refer to Table 2 for desiccant quantity per vessel.
Table 2
DESICCANT REQUIREMENTS
Dryer Model No Lbs. Desiccant per
Tower
EHD275 163
EHD360 215
EHD500 295
EHD650 385
EHD820 484
EHD1000 592
EHD1225 728
EHD1500 894
EHD1700 1024
EHD2000 1198
EHD2300 1385
EHD3300 1815
To add desiccant:
WARNING
The following procedure provides instructions
for adding the initial desiccant to the vessel. If
replacing desiccant, refer to instructions on
page 1-8. Pressure gauges on both dryer
vessels must indicates 0 psig.
1. Remove the relief valve from the desiccant fill port
at the top of each vessel. The connections are la-
beled “DESICCANT INSPECTION PORT.”
CAUTION
Do not tamp the desiccant in vessels. Tamping
damages desiccant and causes dusting.
Pouring desiccant creates a fine dust; safety
goggles, gloves and dust mask should be
worn by personnel installing desiccant. Refer
to the Material Safety Data Sheets (MSDS) on
page 1-14 for more complete information.
2. Carefully pour activated alumina into the vessels
through the fill port.
3. Tap the vessels with a rubber mallet to ensure uni-
form distribution of the desiccant.
4. Reinstall the valves in the fill port connections.
Muffler
A purge exhaust muffler is supplied with every dryer.
WARNING
Operating dryer without muffler will cause
noise levels exceeding OSHA standards.
Remove muffler only for servicing and
maintenance and only after internal pressure
of dryer has been completely vented to
atmosphere.
Electrical Connections
The dryer is prewired, ready for use. Connect the dryer
to the power supply specified on the data plate. Connec-
tions, marked L1, L2 and L3 (3 phase only), are on a
terminal strip inside the electrical box. Make connec-
tions through a hole on the bottom of the lower box.
DANGER
Ground the dryer using the connection
supplied inside the electrical box. Refer to the
electrical schematic for connection details.
INSTRUMENTATION
The EHD dryer is equipped with a microprocessor sys-
tem that controls the operation of all dryer functions.
The controller is programmed to operate the dryer on an
eight-hour cycle. The controller keeps the drying vessel
on line for four hours while simultaneously regenerating
the off-line vessel. Standard and optional indicators on
the controller help in monitoring dryer operation and
performance.
EHD Series (Bulletin 355) 1-3

The dryer sequence indicators include:
•Power On
•Left Tower Drying
•Right Tower Drying
•Depressurizing
•Heating
•Cool Air Purge
•Repressurizing
Switch Failure Alarm
Pressure sensors trigger an alarm, labeled VALVE
SWITCHING FAILURE, if a vessel does not depressur-
ize at the completion of its drying cycle. Refer to the
Field Service Guide in this manual for remedies.
Heater Temperature Alarm
This alarm, labeled HEATER OVER TEMPERATURE,
provides warning of excessive purge air temperature.
When this alarm is triggered the heater shuts off and a
vessel cool down process begins. To resume normal
dryer operation troubleshoot and correct the problem
then push the manual reset button on the door of the
control panel.
High-Humidity Alarm (Optional)
A moisture sensor in the dryer outlet manifold monitors
the relative humidity of the outlet air. The sensor trig-
gers an alarm, labeled HIGH HUMIDITY WARNING,
if the relative humidity of the outlet air exceeds the fac-
tory setting. A set-plug adjustment bulb (refer to Figure
4) is included for use in calibrating the high-humidity
alarm. Refer to the maintenance section of this manual
for field adjustment instructions.
AIRSaver Control (Optional)
The optional AIRSaver control matches purge air and
heater usage to actual dryer load. The control monitors
the dew point of the outlet air and adjusts the dryer cy-
cle according to the dew point achieved and the dew
point specified. It includes a panel-mounted digital dew
point display and high dew point alarm contacts. Two
indicating lights on the dryer controller panel indicate
when the AIRSaver is activated.
Dew Point Monitor (Optional)
The monitor, located between the vessels, continuously
displays outlet pressure dew point. (Consult the owner’s
manual supplied with the monitor for more informa-
tion.) Note: the dew point monitor is off line at tower
changeover to prevent temperature spikes from damag-
ing the dew point probe.
Remote Alarm Contacts
Common contacts for remote annunciators for all alarms
are connected to the terminal strip in the electrical en-
closure; refer to the electrical schematic for terminal
numbers.
Moisture Indicator (Optional)
A color-change moisture indicator is installed in the
manifold. The indicator is green when dry. The color
changes to yellow when the relative humidity of the
dryer outlet air is approximately 4%-5%. This indicator
is intended only as an inexpensive means of determin-
ing possible dryer malfunction.
Vessel Temperature Gauges
A gauge mounted on each desiccant vessel indicates the
temperature inside the vessel.
Vessel Pressure Gauges
A gauge mounted on each desiccant vessel indicates the
pressure inside the vessel.
OPERATION
How It Works
EHD Series dryers provide a continuous supply of dry
compressed air by automatically cycling the flow of air
through two desiccant beds. While one bed is adsorbing
moisture from the inlet air, the other bed is being reacti-
vated. Reactivation is accomplished by diverting a por-
tion of the inlet process air through a venturi (PS
Module) which also draws ambient air into the purge
line. This combination of inlet air and ambient air is
then passed through a heater. The heated air is used to
regenerate the offstream vessel. Cycling is controlled by
a microprocessor. The schematic diagram, Figure 1,
shows the airflow through the dryer with vessel A on-
stream and vessel B being reactivated.
Incoming wet inlet air is divided into two streams. With
switching valve C closed and switching valve B open
most of the air flows downward through vessel A where
moisture is removed from the airstream by the desic-
cant. Dry air exits the dryer through outlet check valve
I.
1-4 EHD Series (Bulletin 355)

A portion of the inlet air is channeled through solenoid
valve PJV into the PS Module where it is combined
with ambient air. This combination of process inlet air
and ambient air is passed through a heater which ex-
pands the air’s moisture holding capacity. The heated
purge air flows through purge check valve H, up
through vessel B, through purge valve D and out
through the purge muffler, carrying away moisture ad-
sorbed by the desiccant in the previous cycle. During
periods of low plant air consumption, auxiliary purge
check valve K feeds purge air back to the dryer elimi-
nating excessive compressor cycling.
The dryer operates this way for three hours, 30 minutes.
Then the regenerating vessel goes through a cool-down
cycle: the heater turns off, solenoid valve PJV closes
and solenoid valve E opens allowing cool, dry air from
the dryer outlet to flow through vessel B. After a mini-
mum of 15 minutes, purge valve D closes and vessel B
is repressurized to line pressure. Then solenoid valve E
closes, purge valve A opens, switching valve C opens
and switching valve B closes, allowing vessel B to start
drying the incoming air and vessel A to start regenerat-
ing. This cycle is repeated every four hours for a total
time cycle of eight hours.
EHD Series (Bulletin 355) 1-5
MUFFLER
VESSEL
A
VESSEL
B
RELIEF
VALVE
INLET
HEATER
FILTER
1TC
PURGE
TEMPERATURE
CONTROL
CONTROL
2TC
TEMPERATURE
HEATER
PURGE CHECK
VALVE (G)
LEFT SWITCHING
VALVE (B)
LEFT PURGE
VALVE (A) VALVE (D)
RIGHT PURGE
VALVE (C)
RIGHT SWITCHING
TO SOL BC
TO SOL CC
VESSEL
PRESSURE
GAUGE
VESSEL
TEMPERATURE
GAUGE
PS MODULE
PURGE
VALVE (N.C.)
(SOL PJV)
SILENCER
INTAKE FILTER/
1PS
(SWITCH
FAILURE)
(SWITCH
FAILURE)
2PS
VALVE (SOL E)
SWEEP/REPRESSURIZATION
ORIFICE
OUTLET
OUTLET CHECK
VALVE (J)
OUTLET CHECK
VALVE (I)
PURGE
CHECK
VALVE (H)
FLOW
RESTRICTOR
MEC
TO SOL AC
TO SOL DC
ADJ. VALVE (L)
PURGE
GAUGE
PURGE
GAUGE
TEMP
CHECK (K)
PURGE
AUXILIARY
Figure 1
AIRFLOW SCHEMATIC

Automatic purge air temperature control: A sensor
monitors the temperature of the purge air exiting the
dryer. If the purge air temperature reaches 150°F the
heater shuts off and the regenerating vessel is cooled
down, repressurized and put in a standby mode until the
on line vessel has completed its drying cycle.
START-UP
Once the EHD Series dryer has been installed according
to instructions, it is ready to be operated. The dryer is
fully automatic and does not require any auxiliary con-
trols.
To start the dryer:
1. Close the customer-supplied letdown valve and the
shutoff valve downstream of the dryer and afterfil-
ter.
2. Open the customer-supplied bypass valve.
3. Slowly open the customer-supplied shutoff valve
upstream of the dryer and prefilter to pressurize the
dryer until both vessels reach line pressure.
4. Turn on the power switch located on the control en-
closure. Depending on the position of the switching
valve and specified operating pressure, one of the
vessels will depressurize, or both vessels will re-
main pressurized for up to five minutes, then one
will depressurize.
5. Slowly open the outlet shutoff valve.
6. Close the dryer bypass valve.
7. Adjust the purge flow when in heating mode.
PS Module Valve Setting
To verify the PS module valve setting during start-up:
When the dryer has cycled into heating mode, check the
pressure gauge mounted near the PS module. The pres-
sure on this gauge will correspond to a flow in scfm on
the graph provided with your dryer. The recommended
flow for this dryer is listed on the lower righthand side
of the graph. Opening the ball valve before the PS mod-
ule will increase the flow; closing the valve will de-
crease the flow. Adjust the ball valve until the
recommended flow is obtained.
Note: Increasing the flow by opening the valve beyond
the recommended value will waste purge air. Reducing
the flow by closing the valve beyond the recommended
value will cause the heaters to overheat. The controller
will respond by shutting down the unit on an over
temperature alarm.
The valve adjustment is set at the factory during the
dryer functional test. However, it is necessary to verify
that the setting was not disturbed in shipment or during
installation.
MAINTENANCE
Shutdown
If the dryer or the air system is shut down desiccant life
can be prolonged by venting the dryer internal pressure
to the atmosphere.
DANGER
EXPLOSION HAZARD
Dismantling or working on any component of
the compressed air system under pressure
may cause equipment damage and serious
injury. Before dismantling any part of the dryer
or compressed air system, completely vent
the internal air pressure to the atmosphere.
To vent dryer pressure:
1. Turn the power switch OFF.
2. Open the customer-supplied bypass valve (if in-
stalled).
3. Close the customer-supplied shutoff valve down-
stream of the dryer.
4. Close the customer-supplied shutoff valve upstream
of the dryer.
5. Slowly open the customer-supplied depressurization
valve to vent the dryer internal air pressure.
6. When the internal air pressure is 0 psig, close the
depressurization valve.
Restart the dryer according to the start-up instructions.
If electrical maintenance must be performed on the
dryer, electrical power to the dryer must be locked out
and tagged in accordance with OSHA requirements.
1-6 EHD Series (Bulletin 355)

DANGER
SHOCK HAZARD
Portions of the electrical control circuit remain
energized when the power switch is turned
OFF. Disconnect the main power supply to the
dryer before performing maintenance on the
electrical system.
Before performing electrical maintenance:
1. Turn the power switch off.
2. Disconnect the main power supply.
Desiccant Dusting
The dryer vessels for models EHD275 through EHD650
are shipped filled with desiccant. Some dusting will oc-
cur from movement of the desiccant during shipping.
Maintenance Schedule
The following periodic checks should be made to moni-
tor dryer operation. These inspections will help you
schedule servicing to ensure continuing good dryer per-
formance and safe operation.
DANGER
The air compressor should be checked for oil
carryover as required by the manufacturer.
Excessive oil carryover could lead to an in-line
fire.
CAUTION
Contact your local distributor before doing
any work on the solid state controls.
Attempting to service circuit boards or
components may result in equipment damage
and will void the warranty.
Daily
1. Check drain valve on prefilter for discharge. (A pre-
filter with drain valve should be installed upstream
of the dryer to protect the desiccant; see Installation,
page 1-1.) If no condensate discharges from drain
valve, follow Shutdown procedure, then dismantle
and clean, repair or replace drain valve as required.
2. Check system monitoring lights on controller panel.
If any warning light is lit, see explanations in the In-
strumentation section (page 1-3) for diagnosis and
Field Service Guide (page 1-10) for remedy.
3. Inspect the filter at the intake to the PS Module.
Clean if necessary. (In very dusty ambient condi-
tions this filter may have to be cleaned every day.)
The filter can be cleaned after removal by light
brushing or vacuuming. Use low pressure air or
gently tap element on flat surface. Failure to clean
this filter may result in high dew points.
Check the following options as applicable:
4. Check the color of the moisture indicator in the
dryer outlet. When the dryer is functioning nor-
mally, the indicator is green. If the indicator is yel-
low, refer to the Field Service Guide on page 1-10
for remedy.
5. Check the switch-failure alarm light on the control
panel. If the light is on, refer to the Field Service
Guide for remedy.
6. Check the high-humidity alarm light on the control
panel. If the light is on, refer to the Field Service
Guide for remedy.
Weekly
1. Check prefilter and afterfilter differential pressure
indicators. Replace filter elements in accordance
with manufacturer’s directions.
2. Check exhaust muffler for discharge of air from re-
generating vessel. If no air discharges from muffler
during heating or cool air purge mode, call your lo-
cal distributor.
Quarterly
1. Replace filter at intake to PS Module. (Depending
on ambient conditions, the filter may have to be re-
placed on a more frequent basis.)
2. Check dew point accuracy of AIRSaver/dew point
monitor and have recalibrated by factory as neces-
sary or every six months.
Yearly
Inspect desiccant in dryer vessels. Depressurize dryer
according to Shutdown section of this manual. Check
for the following and correct as indicated:
1. Oil Contamination
If desiccant is contaminated with oil, check drain
valve on prefilter. Clean, repair or replace drain
valve as necessary. Replace prefilter element, then
replace desiccant.
2. Broken Desiccant (excessive dusting)
Desiccant dusting may be caused by air flow surges,
EHD Series (Bulletin 355) 1-7

excessive air flow or pulsating air pressure. Check
and correct these conditions, then replace desiccant.
3. Replace all solenoid valve seats.
4. Check all moving parts in check valves. Replace as
necessary.
Returns to Manufacturer
If the dryer or a component of the dryer must be re-
turned to the manufacturer, first call your local distribu-
tor for a return authorization number and a shipping
address. Your distributor will inform you whether the
dryer or only the component must be returned.
Desiccant Replacement
To ensure consistent dryer performance and to prevent
excessive dusting or premature desiccant breakdown,
use only factory-supplied activated alumina when re-
placing desiccant.
To replace desiccant:
DANGER
EXPLOSION HAZARD
Completely vent the internal air pressure to
the atmosphere before replacing the
desiccant or performing any maintenance
work on your dryer. Pressure gauges on both
dryer vessels must indicate 0 psig.
1. Depressurize dryer according to the shutdown in-
structions on page 1-6. Pressure gauges on both ves-
sels must indicate 0 psig before service continues.
DANGER
SHOCK HAZARD
Portions of the electrical control circuit remain
energized when the power switch is turned
OFF. Disconnect the main power supply to the
dryer before performing maintenance on the
electrical system.
2. Turn off power switch on control panel.
3. Disconnect the main power supply to the dryer.
4. Lock out and tag electrical power supply in accor-
dance with OSHA requirements.
5. Place large containers under drain outlets at bottom
of vessels to collect desiccant.
6. Remove desiccant drain plug (refer to Figure 2).
7. Tap sides of vessels with rubber mallet to loosen
desiccant.
8. Remove fill plug at top of each vessel.
9. Shine flashlight through fill port and inspect inside
of vessels to be sure all desiccant is removed.
10. Replace desiccant drain plug.
11. Determine the amount of desiccant according to Ta-
ble 2 on page 1-3.
CAUTION
Do not tamp desiccant in vessels. Tamping
damages desiccant and causes dusting.
Pouring desiccant creates a fine dust; safety
goggles, gloves and dust mask should be
worn by personnel installing desiccant. Refer
to the Material Safety Data Sheets (MSDS) on
page 1-14 for more complete information.
12. Carefully pour required desiccant into vessels
through fill ports. Tap vessels with rubber mallet to
ensure uniform distribution of desiccant.
1-8 EHD Series (Bulletin 355)
Figure 2
DESICCANT DRAIN/FILL PORTS

13. Replace fill plugs at top of vessels.
Restart the dryer according to the start-up instructions
on page 1-6.
Purge Field Adjustment
To adjust the amount of purge flow, adjust the purge ad-
justment valve L (Figure 1, page 1-5) so that the pres-
sure indicated by the pressure gauge immediately
downstream reads a pressure which corresponds to the
desired purge flow as indicated by the purge adjustment
graph (supplied with the dryer).
High-Humidity Alarm Field Adjustment
The high-humidity alarm is an optional feature on EHD
Series dryers; it is indicated by the suffix H in the model
number on the dryer nameplate.
To set the high-humidity alarm:
1. Turn power switch OFF.
DANGER
SHOCK HAZARD
Portions of the electrical control circuit remain
energized when the power switch is turned
OFF. Disconnect the main power supply to the
dryer before performing maintenance on the
electrical system.
2. Open the door of the electrical control box.
3. Locate the high-humidity alarm circuit board (refer
to Figure 3).
4. A calibrated set plug (refer to Figure 4) is shipped
loose inside the electrical box. The set plug is used
to select the setting at which the high-humidity
alarm sounds. To insert the set plug, unplug the flat
brown 2-wire ribbon cable in the electrical box. In-
sert the set plug into the ribbon cable socket.
5. Turn the power switch to ON.
6. With a small slotted screwdriver, adjust P1 on the
high-humidity circuit board (Figure 3) clockwise
and counterclockwise. Find the adjustment point
where the contacts open and close. Leave adjust-
ment where the contacts just close.
NOTE: DO NOT ADJUST POTENTIOMETER
P3.
7. Put a drop of lacquer on potentiometer P1 to pre-
vent vibrations from altering the setting.
8. Turn the power switch to OFF.
9. Remove the set plug and reinsert the ribbon cable.
The high-humidity alarm is now set.
To put the dryer back into service, follow the start-up
instructions on page 1-6.
EHD Series (Bulletin 355) 1-9
Figure 4
SET PLUG
Figure 3
HIGH HUMIDITY ALARM CIRCUIT BOARD
POTENTIOMETERS P1 AND P3

FIELD SERVICE GUIDE
WARNING
Compressed air can be dangerous unless
safety precautions are observed in the use of
compressed air and compressed air
equipment. Completely vent the internal air
pressure to the atmosphere before
disassembling any piping, fittings, valves or
other components and before doing any work
on compressed air equipment. To vent internal
air pressure, follow the shutdown instructions.
1-10 EHD Series (Bulletin 355)
Problem Possible Cause Remedy
Dew point too high
or too low
Inlet air flow higher than the
sizing condition. Reduce inlet flow to sizing conditions.
Liquids entering the dryer inlet. Check the inlet air line for liquids. Inspect prefilter and drain
valve. Clean, repair or replace automatic drain valve.
Inlet air temperature higher
than the sizing condition.
Check the compressor aftercooler and cooling system.
Reduce inlet air temperature to sizing condition.
Desiccant dusting. Check air pressure, airflow and airflow surges and correct as
necessary. Replace desiccant.
Desiccant coated with oil.
Check prefilter and automatic drain valve. Replace prefilter
element. Clean, repair or replace drain valve as necessary.
Consult factory concerning need for desiccant replacement.
Clogged PS Module intake
filter. Clean or replace filter.
Burned out heater(s). Replace heater(s).
Purge solenoid failure. Clean or replace solenoid.
Excessive
pressure drop in
prefilter and/or
afterfilter
Filter elements dirty. Replace elements.
Excessive
pressure drop in
dryer
Inlet and/or outlet screens on
desiccant towers dirty.
Clean or replace screens; follow desiccant removal
instructions in Maintenance section, then disconnect inlet
and outlet piping to remove screens.
Excessive flow rate. Check flow rate of inlet air. Reduce to sizing condition.
Failure to switch
Power failure.
1. Check power with voltmeter.
2. Check dryer fuses in the electrical enclosures. Replace as
necessary.
Solenoid valve stuck shut. Replace solenoid coil or complete valve.
Solenoid valve stuck open. Remove, dismantle and clean.
Dryer cuts off
automatically Power failure.
1. Check power with voltmeter.
2. Check dryer fuses in the electrical enclosures. Replace as
necessary.

EHD Series (Bulletin 355) 1-11
Table 3
INLET AIRFLOW AT VARIOUS INLET AIR PRESSURES
Model
Maximum
Inlet Air
Pressure
(psig)1
Inlet Air Pressure (psig) Recommended
Filters3
60 70 80 90 100 110 125 150
Average Inlet Airflow (scfm)2Prefilter Afterfilter
EHD275 150 179 203 227 251 275 299 335 395 IR300C IR300PT
EHD360 150 234 266 297 329 360 391 438 517 IR400C IR400PT
EHD500 150 326 369 413 456 500 544 609 718 IR600C IR500PT
EHD650 150 423 480 537 593 650 707 792 933 IR950C IR750PT
EHD820 150 534 606 677 749 820 891 999 1177 IR950C IR1000PT
EHD1000 150 651 738 826 913 1000 1087 1218 1436 IR1600C IR1000PT
EHD1225 150 798 905 1011 1118 1225 1332 1492 1759 IR1600C IR1500PT
EHD1500 150 977 1108 1238 1369 1500 1631 1827 2154 IR1600C IR1500PT
EHD1700 150 1107 1255 1404 1552 1700 1848 2071 2441 IR1900C IR2000PT
EHD2000 150 1303 1477 1651 1826 2000 2174 2436 2872 IR2550C IR2000PT
EHD2300 150 1498 1698 1899 2099 2300 2501 2801 3303 IR3000C IR3000PT
EHD3300 150 2149 2437 2725 3012 3300 3588 4019 4739 IR4000C IR4000PT
1Higher pressures available as an option on some models; consult your local distributor.
2Based on 100°F inlet air temperature. Maximum recommended inlet temperature, 120°F.
For capacity at inlet temperature higher than 100°F, consult your local distributor.
3Based on –40°F PDP, 100 psig inlet air pressure and average inlet airflow.

1-12 EHD Series (Bulletin 355)
TROUBLESHOOTING GUIDE
EHD Sequence of Operation
Solenoid A: Left Purge Exhaust Valve
Solenoid B: Left Inlet Valve
Solenoid C: Right Inlet Valve
Solenoid D: Right Purge Exhaust Valve
Solenoid E: Repressurization Valve
Solenoid F: Left Let Down Valve
Solenoid G: Right Let Down Valve
Solenoid PJV: Purge Jet Valve
Solenoid SIV: Sensor Isolation Valve
1PC: Heater Contactor
Time (Minutes) Operation Display Panel LEDs
5
Solenoid D energized
Right Exhaust Valve opens
Solenoid G de-energized
Right Depressurizing Valve
closes
Solenoid PJV energized
Purge Jet Valve opens
1PC energized
Heater energized
Right Tower Depressurized LED on
Heater On LED on
Left Tower Drying LED on
Time (Minutes) Operation Display Panel LEDs
205
Solenoid PJV de-energized
Purge Jet Valve closes
1PC de-energized
Heater de-energized
Solenoid E energized
Repressurizing Valve opens
Left Tower Drying LED on
Cool Air Purge LED on
Time (Minutes) Operation Display Panel LEDs
235 Solenoid D de-energized
Right Exhaust Valve closes
Right Tower Repressurizing LED on
Left Tower Drying LED on
Time (Minutes) Operation Display Panel LEDs
240
Solenoid E de-energized
Repressurizing Valve closes
Solenoid B energized/Solenoid C
de-energized
Left Inlet Valve closes
Right Inlet Valve opens
Solenoid F energized
Left Depressurizing Valve
opens
Right Tower Drying LED on
Switch Towers left to right
Left Tower Depressurizing LED on

EHD Series (Bulletin 355) 1-13
Time (Minutes) Operation Display Panel LEDs
245
Solenoid A energized
Left Exhaust Valve opens
Solenoid F de-energized
Left Depressurizing Valve
closes
Solenoid PJV energized
Purge Jet Valve opens
1PC energized
Heater energized
Left Tower depressurizes
Right Tower Drying LED on
Heating LED on
Time (Minutes) Operation Display Panel LEDs
445
Solenoid PJV de-energized
Purge Jet Valve closes
1PC de-energized
Heater de-energized
Solenoid E energized
Repressurizing Valve opens
Right Tower Drying LED on
Cool Air Purge LED on
Time (Minutes) Operation Display Panel LEDs
475 Solenoid A de-energized
Left Exhaust Valve closes
Left Tower Repressurizing LED on
Right Tower Drying LED on
Time (Minutes) Operation Display Panel LEDs
480/0 Cycle repeats

Material Safety Data Sheet
Date: March 1996
Emergency Phone
1-800-424-9300 (Chemtrec)
Only for use in the event of a chemical emergency
involving a spill, leak, fire, exposure or accident.
ACTIVATED
ALUMINAS
SECTION 1. CHEMICAL PRODUCT AND COMPANY IDENTIFICATION
Chemical: Aluminum Oxide Al2O3•xH2O
Product Name: Activated Aluminas
SECTION 2. COMPOSITION/INFORMATION ON INGREDIENTS
Component CAS Number Exposure Limits Typical % by Weight
Aluminum oxide 1333-84-2 ACGIH TLV 10 mg/m3
OSHA PEL 15, 5 mg/m3respirable 90.0 – 97.0
Silicon dioxide* — — 0.01 – 0.2
* Expressed as oxide equivalent
SECTION 3. HAZARDS IDENTIFICATION
EMERGENCY OVERVIEW
No unusual fire or spill hazard. Dust may be irritating to eyes and upper respiratory tract. Off-white crystal-
line or gelatinous granules, pellets, or powder.
Potential Health Effects
Eyes: May cause irritation due to desiccant properties.
Skin: None.
Inhalation: May cause irritation of upper respiratory tract due to desiccant properties.
This product contains silicates at <1% by weight. Silicates include metal silicates, amorphous and crystalline silica.
No analytical method exists to detect and differentiate between amorphous and crystalline silica and other silicates at
<1% by weight. Based on the chemistry of bauxite-derived products, crystalline silica is not expected to be present
in this product.
Alumina is a low health risk by inhalation and should be treated as a nuisance dust as specified by the American
Conference of Governmental Industrial Hygienists (ACGIH).
SECTION 4. FIRST AID MEASURES
Eyes: Flush eyes with plenty of water for at least 15 minutes. If irritation persists, consult a physician.
Skin: Wash with soap and warm water. If irritation develops, consult a physician.
Inhalation: Remove victim to fresh air. If not breathing, give artificial respiration. Get immediate medical attention.
1-14 EHD Series (Bulletin 355)

SECTION 5. FIRE FIGHTING MEASURES
Flammable Properties: Non-flammable
Flash Point: None.
Flammable Limits: None.
Auto-Ignition Temperature: Not applicable.
Hazardous Combustion Products: None.
Extinguishing Media: Use extinguishing agent applicable to surrounding fire.
Firefighting Instructions: Firefighter should wear NIOSH approved, positive pressure, self-contained breathing
apparatus and full protective clothing when appropriate.
SECTION 6. ACCIDENTAL RELEASE MEASURES
Small/Large Spill: Clean up using dry procedures; avoid dusting.
SECTION 7. HANDLING AND STORAGE
Handling: Avoid contact with eyes. Do not inhale dust.
Storage: Keep material dry.
SECTION 8. EXPOSURE CONTROL/PERSONAL PROTECTION
Engineering Controls: Use with adequate ventilation to meet exposure limits listed in Section 2.
Respiratory Protection: NIOSH-approved dust respirator where exposure limit is or may be exceeded.
Skin Protection: None.
Eye Protection: Safety glasses recommended.
SECTION 9. PHYSICAL AND CHEMICAL PROPERTIES
Appearance: Off-white, crystalline or gelatinous granules, pellets, or powder.
Boiling Point: Not applicable.
Freeze-Melt Point: 3700°F (2038°C)
Vapor Pressure (mm): Not applicable.
Vapor Density (air = 1): Not applicable.
Solubility in Water: Insoluble; soluble in concentrated acids and alkalies.
Specific Gravity: 3.2
Density: Loose Bulk: 39 – 52 lb/ft3(0.62 – 0.83 g/cm3).
pH: ~10 (20% slurry solution)
Odor: None.
Odor Threshold (ppm): Not applicable.
Coefficient of Water/Oil Distribution: Not applicable.
SECTION 10. STABILITY AND REACTIVITY
Chemical Stability (conditions to avoid): Avoid water.
Incompatibility: None.
Hazardous Decomposition Products: None.
Hazardous Polymerization: None.
Generates heat with water.
Non-corrosive.
EHD Series (Bulletin 355) 1-15

SECTION 11. TOXICOLOGICAL INFORMATION
No LD50 or LC50 found for oral, dermal or inhalation routes of administration.
SECTION 12. ECOLOGICAL INFORMATION
Ecotoxicological/Chemical Fate Information: Not available.
SECTION 13. DISPOSAL CONSIDERATION
Collect in containers, bags, or covered dumpster boxes. If reuse or recycling is not possible, material may be dis-
posed of at a sanitary landfill.
TCLP data are available.
RCRA Hazardous Waste No: Not federally regulated.
SECTION 14. TRANSPORT INFORMATION
Not regulated by U.S.A. DOT.
Canadian TDG Hazard Class & PIN – Not regulated.
SECTION 15. REGULATORY INFORMATION
For inventory purposes, CAS No. 1344-28-1 was assigned for aluminum hydroxide and activated alumina products
instead of the CAS number indicated in Section 2.
This material does not contain nor was it manufactured using ozone-depleting chemicals.
U.S. FEDERAL REGULATIONS:
TSCA Status: On Toxic Substances Control Act Inventory.
CERCLA Reportable Quantity: None.
SARA Title III
Section 302 Extremely Hazardous Substances: None.
Section 311/312 Hazardous Categories: Immediate (Acute).
Section 313 Toxic Chemicals: None.
RCRA Status: Not regulated.
INTERNATIONAL REGULATIONS:
Canadian WHMIS: Listed on Domestic Substances List.
EINECS: All components of this product are on the European Inventory of Existing Commercial Chemical
Substances.
Information herein is given in good faith as authoritative and valid; however, no warranty, express or implied, can be made.
1-16 EHD Series (Bulletin 355)

Serie EHD (Boletín 355) 2-1
EHD275
EHD360
EHD500
EHD650
EHD820
EHD1000
EHD1225
EHD1500
EHD1700
EHD2000
EHD2300
EHD3300
Antes de instalar o arrancar el secador por
primera vez, estudie este manual
cuidosamente para obtener un conocimiento
claro del secador y de las tareas a desempeñar
mientras opere y preste mantenimiento al
secador.
CONSERVE ESTE MANUAL CON LA UNIDAD.
Este manual técnico contiene INFORMACION
IMPORTANTE DE SEGURIDAD y debe
mantenerse con el secador todo el tiempo. Boletín 355 Revisión F (9/99)
©1999 Ingersoll-Rand Company
SECADORES DE AIRE COMPRIMIDO CON
CALENTADOR EXTERNO
SERIE EHD
MANUEL DE INSTRUCCIONES
DEL OPERADORS

2-2 Serie EHD (Boletín 355)
Tabla de Contenidos
INTRODUCCION ..........................2-3
SEGURIDAD .............................2-3
Instrucciones de seguridad ..................2-3
Placa del Secador .......................2-4
INSTALACIÓN............................2-4
Recepción e Inspección ....................2-4
Manipulación .........................2-4
Temperatura ambiente ....................2-4
Localización y espacio libre .................2-4
Preparativos del sistema ...................2-4
Conexiones y tubería .....................2-5
Desecante ...........................2-5
Mofle (Silenciador) ......................2-6
Conexiones eléctricas .....................2-6
INSTRUMENTACION........................2-6
Alarma de Fallo en Cambio de Válvula ...........2-6
Alarma de alta humedad (Opcional) .............2-6
AIRSaver Control [Control Ahorra Purga] (Opcional) ....2-7
Monitor de Punto De Rocío (Opcional) ...........2-7
Contactos de Alarmas Remotas................2-7
Indicador de humedad (opcional) ...............2-7
Indicadores de Temperatura de Torre.............2-7
Indicadores de Presion de Torre ...............2-7
OPERACION .............................2-7
Como Trabaja .........................2-7
ARRANQUE .............................2-8
Ajustes de la Válvula Modulo PS...............2-9
MANTENIMIENTO.........................2-9
Apague Total .........................2-9
Pulverización de Desecante ..................2-9
Rutina De Mantenimiento ..................2-9
Diario ............................2-10
Anual ............................2-10
Retorno a la fábrica .....................2-10
Reemplazo de Desecante ..................2-11
Ajuste de Purga .......................2-12
Ajustes de Alarma de Alta Humedad ............2-12
GUIADESERVICIO........................2-13
GUIA DE VERIFICACION DE SISTEMA ............2-16
Sequencia de Operacion de Secadores EHD ........2-16
PARTES DE REPUESTO ......................A-1
ILUSTRACIONES DE REFERENCIA ..............A-1