ICP iDRY iRDP CT 30 User guide

1
Compressed air refrigeration dryer
iRDP CT 20-500
Instructions for installation and operation english

2 iDRY iRDP CT 20-500
Dear customer,
Thank you for deciding in favour of the iDRY iRDP CT 20-500 compressed-air refrigeration dryer. Please read these
installation and operating instructions carefully before mounting and starting up the iDRY iRDP CT 20-500 and follow
our directions. Perfect functioning of the iDRY iRDP CT 20-500 and thus reliable compressed-air drying can only be
guaranteed when the provisions and notes stipulated here are strictly adhered to.

iDRY iRDP CT 20-500 3
Contents
1Type plate 5
2Safety instructions 5
2.1Safety pictograms in accordance with DIN 4844 6
2.2Signal words in accordance with ANSI 8
2.3Overview of the safety instructions 8
3Proper use 11
4Exclusion from a field of application 11
5Operating instructions in accordance with the 97/23/EC Pressure Equipment Directive 11
6Transport 12
7Storage 12
8Technical description 13
8.1Control panel 13
8.2Functional description 14
8.3Flow chart 15
8.4Refrigerating compressor 16
8.5Condenser 16
8.6Filter dryer 16
8.7Capillary tube 16
8.8Aluminium heat exchanger 16
8.9Hot-gas bypass valve 17
8.10Refrigerant pressure switches LPS – HPS – PV 17
8.11Compressor crankcase heater (iRDP CT 200-500 3phase) 17
8.12DMC 51 electronics (control unit compressed-air dryer) 18
8.12.1Switching the dryer on 18
8.12.2Switching the dryer off 18
8.12.3Indication of the operating parameters 18
8.12.4Indication of a Service Warning 19
8.12.5Indication of an Alarm 19
8.12.6Operation of the Service Warning / Alarm signal 20
8.12.7How to change operating parameters – SETUP menu 20
8.13Electronically level-controlled iMAT condensate drain 20
9Installation 21
9.1Place of installation 21
9.2Installation plan 22
9.3Correction factors 23
9.4Connection to the compressed-air system 24
9.5Electrical connections 25
9.6Condensate drain 25
10Start-up 26
10.1Preliminary stages 26
10.2Initial start-up 26
10.3Shut down and restart 27
11Technical data 28
11.1Technical data iDRY iRDP CT 20-200 -1 1/115/60 28
11.2Technical data iDRY iRDP CT 20-500 -2 1/230/60 29
11.3Technical data iDRY iRDP CT 200-500 3phase -4 3/460/60 30
12Maintenance, troubleshooting, spare parts and dismantling 31
12.1Checks and maintenance 31
12.2Troubleshooting 32
12.3Recommended spare parts 37
12.4Maintenance works at the refrigeration cycle 40
12.5Dismantling the dryer 40
13Appendices 41
13.1Dryer dimensions 41
13.1.1Dryer dimensions iDRY iRDP CT 20-50 41
13.1.2Dryer dimensions iDRY iRDP CT 75 42
13.1.3Dryer dimensions iDRY iRDP CT 100-150 43

4 iDRY iRDP CT 20-500
13.1.4Dryer dimensions iDRY iRDP CT 200-250 44
13.1.5Dryer dimensions iDRY iRDP CT 300-350 45
13.1.6Dryer dimensions iDRY iRDP CT 400-500 46
13.1.7Dryer dimensions iDRY iRDP CT 200-250 3phase 47
13.1.8Dryer dimensions iDRY iRDP CT 300-350 3phase 48
13.1.9Dryer dimensions iDRY iRDP CT 400-500 3phase 49
13.2Exploded diagrams 50
13.2.1Components of the exploded diagrams 50
13.2.2Exploded diagram iDRY iRDP CT 20-30 51
13.2.3Exploded diagram iDRY iRDP CT 50 52
13.2.4Exploded diagram iDRY iRDP CT 75 53
13.2.5Exploded diagram iDRY iRDP CT 100 54
13.2.6Exploded diagram iDRY iRDP CT 125-150 55
13.2.7Exploded diagram iDRY iRDP CT 200-250 56
13.2.8Exploded diagram iDRY iRDP CT 300-350 57
13.2.9Exploded diagram iDRY iRDP CT 400-500 58
13.2.10Exploded diagram iDRY iRDP CT 200-250 3phase 59
13.2.11Exploded diagram iDRY iRDP CT 300-350 3phase 60
13.2.12Exploded diagram iDRY iRDP CT 400-500 3phase 61
13.3Electric diagrams 62
13.3.1Electric diagrams – list of components 62
13.3.2Electric diagram iDRY iRDP CT 20-100 63
13.3.3Electric diagram iDRY iRDP CT 125-150 64
13.3.4Electric diagram iDRY iRDP CT 200-250 65
13.3.5Electric diagram iDRY iRDP CT 300-350 66
13.3.6Electric diagram iDRY iRDP CT 400-500 67
13.3.7Electric diagram iDRY iRDP CT 200-500 3phase 1/3 68
13.3.8Electric diagram iDRY iRDP CT 200-500 3phase 2/3 69
13.3.9Electric diagram iDRY iRDP CT 200-500 3phase 3/3 70
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Type plate
iDRY iRDP CT 20-500 5
1 Type plate
The type plate is on the back of the dryer and comprises all primary data of the device. Always refer to these when
contacting the manufacturer or the sales department.
All guarantee claims will expire in the event that the type plate is modified or removed.
The dryer model printed on the typeplate includes one or more suffixes that specify one or more features of dryer.
2 Safety instructions
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Please check whether or not these instructions correspond to the device type.
Please adhere to all advice given in these operating instructions. They include essential information
which must be observed during installation, operation and maintenance. Therefore, it must be ensured
that these operating instructions are read by the fitter and the responsible operator / certified skilled
personnel prior to installation, start-up and maintenance.
The operating instructions must be accessible at all times at the place of application of the iDRY iRDP
CT 20-500 compressed-air refrigeration dryer.
In addition to these operating instructions, local and national regulations need to be observed, where
required .
Ensure that operation of the iDRY iRDP CT 20-500 compressed-air refrigeration dryer only takes place
within the permissible limit values indicated on the type plate. Any deviation from these limit values
involves a risk for persons and for the material, and may result in malfunction or a breakdown.
After installing the device correctly and in accordance with the instructions in this manual, the dryer is
ready to operate, further settings are not required. Operation is fully automatic and maintenance is
limited to several examinations and cleaning measures which are described in the following chapters.
This manual must be available at all times for future reference and is a constituent part of the dryer.
If you have any queries regarding these installation and operating instructions, please contact
Independent Compressor Partners at www.icompressorpartners.com.

Safety instructions
6 iDRY iRDP CT 20-500
2.1 Safety pictograms in accordance with DIN 4844
Observe operating instructions
General danger symbol
Supply voltage
Danger: component or system under pressure
Hot surfaces
Non-breathable air
Do not use water to extinguish the fire
Do not operate with open cover (housing)
Maintenance works or controlling measures must only be carried out by qualified personnel1
Do not smoke
Note
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6
ARIA
AIR
LUFT
AIR Connection point compressed-air inlet
ARIA
AIR
LUFT
AIR Connection point compressed-air outlet
Connection point condensate drain
1Certified skilled personnel are persons who are authorised by the manufacturer, with experience and technical training, who are
well-grounded in the respective provisions and laws and capable of carrying out the required works and of identifying and avoiding
any risks during the machine transport, installation, operation and maintenance.
Qualified and authorised operators are persons who are instructed by the manufacturer regarding the handling of the refrigeration
system, with experience and technical training, and who are well-grounded in the respective provisions and laws.

Safety instructions
iDRY iRDP CT 20-500 7
Works can be carried out by the operator of the plant, provided that they are skilled accordingly
2
.
NOTE: Text that contains important specifications to be considered – does not refer to safety precautions.
The device was carefully designed with particular attention paid to environmental protection:
CFC-free refrigerants
CFC-free insulation material
Energy-saving design
Limited acoustic emissions
Dryer and packaging comprise reusable materials
This symbol advises the user to observe the environmental aspects and comply with the recommendations
connected with this symbol.
2Certified skilled personnel are persons who are authorised by the manufacturer, with experience and technical training, who are
well-grounded in the respective provisions and laws and capable of carrying out the required works and of identifying and avoiding
any risks during the machine transport, installation, operation and maintenance.
Qualified and authorised operators are persons who are instructed by the manufacturer regarding the handling of the refrigeration
system, with experience and technical training, and who are well-grounded in the respective provisions and laws.

Safety instructions
8 iDRY iRDP CT 20-500
2.2 Signal words in accordance with ANSI
Danger! Imminent hazard
Consequences of non-observance: serious injury or death
Warning! Potential hazard
Consequences of non-observance: possible serious injury or death
Caution! Imminent hazard
Consequences of non-observance: possible injury or property damage
Notice! Potential hazard
Consequences of non-observance: possible injury or property damage
Important! Additional advice, info, hints
Consequences of non-observance: disadvantages during operation and maintenance, no danger
2.3 Overview of the safety instructions
Certified skilled personnel
Installation works must exclusively be carried out by authorised and qualified skilled personnel. Prior to
undertaking any measures on the iDRY iRDP CT 20-500 compressed-air refrigeration dryer, the
certified skilled personnel shall read up on the device by carefully studying the operating instructions.
The operator is responsible for the adherence to these provisions. The respective directives in force
apply to the qualification and expertise of the certified skilled personnel.
For safe operation, the device must only be installed and operated in accordance with the indications in
the operating instructions. In addition, the national and operational statutory provisions and safety
regulations, as well as the accident prevention regulations required for the respective case of
application, need to be observed during employment. This applies accordingly when accessories are
used.
Danger!
Compressed air!
Risk of serious injury or death through contact with quickly or suddenly escaping compressed
air or through bursting and/or unsecured plant components.
Compressed air is a highly dangerous energy source.
Never work on the dryer when the system is under pressure.
Never direct the compressed-air outlet or condensate drain hoses at persons.
The user is responsible for the proper installation of the dryer. Non-observance of the instructions in the
"Installation" chapter leads to the expiration of the guarantee. Improper installation may result in
dangerous situations for the personnel and/or the device.
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Danger!
Supply voltage!
Contact with non-insulated parts carrying supply voltage involves the risk of an electric shock
resulting in injuries and death.
Only qualified and skilled personnel are authorised to run electrically-operated devices. Prior to
undertaking maintenance measures at the device, the following requirements must be met:
Make sure that the power supply is switched off and that the device is off and marked for maintenance
measures. Please also ensure that the power supply cannot be re-established during the works.
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Caution!
Refrigerant!
The compressed-air refrigeration dryer uses HFC-containing refrigerants as a coolant.
Please observe the corresponding paragraph entitled "Maintenance works at the refrigeration cycle".

Safety instructions
iDRY iRDP CT 20-500 9
Warning!
Refrigerant leak!
A refrigerant leak involves the danger of serious injury and damage to the environment.
The iDRY iRDP CT 20-500 compressed-air refrigeration dryer contains fluorinated greenhouse
gas/refrigerant.
Installation, repair and maintenance works at the refrigeration system must only be carried out by
certified skilled personnel (specialists). A certification in accordance with EC regulation 303/2008 must
be available.
The requirements of the EC 842/2006 directive must be met under all circumstances.
Please refer to the indications on the type plate as regards the type and amount of refrigerant.
Comply with the following protective measures and rules of conduct:
Storage: Keep the container tightly closed. Keep it in a cool and dry place. Protect it against heat
and direct sunlight. Keep it away from ignition sources.
Handling: Take measures against electrostatic charging. Ensure good ventilation/suction at the
workplace. Check fittings, connections and ducts for tightness. Do not inhale the gas. Avoid contact
with the eyes or the skin.
Prior to carrying out works on refrigerant-carrying parts, remove the refrigerant to such an extent
that safe working is possible.
Do not eat, drink or smoke during work. Keep out of the reach of children.
Breathing protection: ambient-air-independent respirator (at high concentrations).
Eye protection: sealing goggles.
Hand protection: protective gloves (e.g. made of leather).
Personal protection: protective clothing.
Skin protection: use protective cream.
In addition, the safety data sheet for the refrigerant needs to be observed!
Caution!
Hot surfaces!
During operation, several components can reach surface temperatures of more than 140°F
(60°C). There is the risk of burns.
All components concerned are installed inside of the closed housing. The housing must only be
opened by certified skilled personnel3.
Caution!
Improper use!
The device is intended for the separation of water in compressed air. The dried air cannot be used for
breathing-air purposes and is not suitable for the direct contact with food.
This dryer is not suitable for the treatment of contaminated air or of air containing solids.
3Certified skilled personnel are persons who are authorised by the manufacturer, with experience and technical training, who are
well-grounded in the respective provisions and laws and capable of carrying out the required works and of identifying and avoiding
any risks during the machine transport, installation, operation and maintenance.
Qualified and authorised operators are persons who are instructed by the manufacturer regarding the handling of the refrigeration
system, with experience and technical training, and who are well-grounded in the respective provisions and laws.

Safety instructions
10 iDRY iRDP CT 20-500
Note!
Contaminated intake air!
In the event that the intake air is strongly contaminated (ISO 8573.1 class 3.-3 or poorer quality), we
recommend the additional installation of an iPUR prefilter to avoid clogging of the heat exchanger.
Caution!
Heating-up through fire!
In the event of a heating-up through fire, the containers and pipes of the refrigerant system can
burst.
In this case, please proceed as follows:
Switch off the refrigeration plant.
Switch off the mechanical ventilation of the machinery compartment.
Use ambient-air-independent respirators.
Containers and plants which are filled with refrigerant can burst violently in the event of fire.
The refrigerants themselves are incombustible, but they are degraded to very toxic products at high
temperatures.
Remove the container/plant from the fire zone, as there is the risk of bursting!
Cool down containers and bottles via a directed water jet from a safe position.
In the event of fire, please use an approved fire extinguisher. Water is not a suitable agent to
extinguish an electrical fire.
This must only be carried out by persons who are trained and informed about the hazards emanating
from the product.
Caution!
Unauthorised intervention!
Unauthorised interventions may endanger persons and plants and lead to malfunction.
Unauthorised interventions, modification and abuse of the pressure devices are prohibited.
The removal of sealings and leadings at safety devices is prohibited.
Operators of the devices must observe the local and national pressure equipment regulations in the
country of installation.
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Note!
Ambient conditions!
In the event that the dryer is not installed under suitable ambient conditions, the ability of the device to
condense refrigerant gas is impaired. This can result in a higher load of the refrigerating compressor,
and in a loss of efficiency and performance of the dryer.
This in turn leads to overheated condenser fan motors, to malfunction of electric components and to a
breakdown of the dryer. Failures of this type will affect warranty considerations.
Do not install the dryer in an environment in which chemicals with a corrosive effect, explosive gases,
toxic gases, evaporation heat, high ambient temperatures or extreme dust and dirt can be found.
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Proper use
iDRY iRDP CT 20-500 11
3 Proper use
This dryer was designed, manufactured and tested to separate the moisture which normally exists in compressed air.
Any other use is considered improper.
The manufacturer shall not be liable for problems occurring as a consequence of improper use. The user alone is
responsible for any damage resulting from that.
Furthermore, the correct use includes the compliance with the installation instructions, in particular in respect of:
• The voltage and frequency of the main voltage supply.
• The pressure, temperature and flow rate of the inlet air.
• The ambient temperature.
When delivered, the dryer is tested and fully assembled. The customer only needs to connect the device to the system
in accordance with the instructions in the following chapters.
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4 Exclusion from a field of application
Note!
Improper use!
The device is intended for the separation of water in compressed air. The dried air cannot be used for
breathing-air purposes and is not suitable for the direct contact with food.
This dryer is not suitable for the treatment of contaminated air or of air containing solids.
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5 Operating instructions in accordance with the 97/23/EC Pressure Equipment Directive
The iDRY iRDP CT 20-500 compressed-air refrigeration dryer contains pressure equipment in the sense of the
97/23/EC Pressure Equipment Directive. Therefore, the entire plant needs to be registered with the supervisory
authority if required in accordance with the local regulations.
For the examination prior to the start-up and for periodic inspections, the national regulations need to be observed,
such as the industrial safety regulation in the United States of America. In countries outside the US, the respective
regulations in force there need to be adhered to.
The proper use of pressure devices is the basic requirement for safe operation. As regards pressure devices, the
following points need to be observed:
The iDRY iRDP CT 20-500 compressed-air refrigeration dryer must only be employed within the pressure and
temperature range limits indicated by the manufacturer on the type plate.
No welding must be carried out on the pressure parts.
The iDRY iRDP CT 20-500 compressed-air refrigeration dryer must neither be installed in insufficiently ventilated
rooms nor near heat sources or inflammable substances.
To avoid fractures resulting from material fatigue, the refrigeration dryer should not be exposed to vibrations during
operation.
The maximum operating pressure indicated by the manufacturer on the type plate must not be exceeded. It is the
installer's responsibility to install the appropriate safety and control devices. Prior to the start-up of the iDRY iRDP
CT 20-500 compressed-air refrigeration dryer, the connected pressure generator (compressor etc.) must be set to
the max. permissible operating pressure. The integrated safeguard needs to be checked by an approved
inspection agency.
The documents related to the iDRY iRDP CT 20-500 compressed-air refrigeration dryer (manual, operating
instructions, manufacturer's declaration etc.) must be kept safe for future reference.
No objects whatsoever must be installed at or placed on the iDRY iRDP CT 20-500 compressed-air refrigeration
dryer and the connecting lines.
Installation of the plant in frost-free places only.
Operation of the plant is only permissible with fully closed and intact housing and cover panels. Operation of the
plant with damaged housing/cover panels is prohibited.

Transport
12 iDRY iRDP CT 20-500
6 Transport
Check the packaging for visible loss or damage. If no visible damage can be ascertained, place the unit in close
proximity to the place of installation and unpack the device.
During this procedure, the dryer must always remain in an upright position. The components may be damaged when
the unit is tilted or turned upside down.
Store the device in a dry environment and do not expose it to extreme weather conditions.
Handle with care. Strong shocks can cause irreparable damage.
7 Storage
SCC0001
Keep the device away from extreme weather conditions
even when packaged.
Keep the dryer in an upright position, also while it is
stored. Tilting the device or turning it upside down can
cause irreparable damage to some components.
When the dryer is not in use, it can be stored in its
packaging in a dust-free and protected place at a
temperature of up to max. 122°F (50°C) and at a specific
humidity of max. 90%. If the storage period exceeds 12
months, you should contact the manufacturer.
The packaging material is recyclable. Dispose of the material in accordance with the
directives and provisions in force in the country of destination

Technical description
iDRY iRDP CT 20-500 13
8 Technical description
8.1 Control panel
The control panel explained below is the only dryer user interface.
iRDP CT 20 –100
K
1
23
PQS0080
1
0
Set reset
K
1Main switch
2 Electronic control unit DMC 51
3 Air and refrigerant gas flow chart
iRDP CT 125 – 500
K
23
PQS0081
1
Set reset
K
1Main switch
2 Electronic control unit DMC 51
3 Air and refrigerant gas flow chart
iRDP CT 200 – 500 3phase
K3
A
PQS0082
T4 T3
T1
T2
0
1
1
2
Set reset
K
A Main switch
1 ON-OFF switch
2 Electronic control unit DMC 51
3 Air and refrigerant-gas flow chart

Technical description
14 iDRY iRDP CT 20-500
8.2 Functional description
Operating principle – All dryer models described in this manual function according to the same principle. The hot and
moisture-loaded air is led into an air/air heat exchanger. Afterwards, the air flows through an evaporator, which is also
known as an air/refrigerant heat exchanger. The air temperature is reduced to approximately 36°F (2°C), so that water
vapour condenses to liquid. The continuously accumulating condensate is collected in the separator to be discharged
via the condensate drain. Subsequently, the cold and dry air is led through the air/air heat exchanger, so that it is
reheated to up to 46°F (8°C) below the inlet temperature when leaving the dryer.
Refrigeration cycle – The refrigerant is conducted through the compressor and reaches a condenser under high
pressure. There, cooling-down takes place, making the refrigerant condense to a liquid state which is under high
pressure. The liquid is pressed through a capillary tube where the resulting pressure drop ensures that the refrigerant
evaporates at a defined temperature. The liquid refrigerant which is under low pressure is led into the heat exchanger,
where it expands. The cold resulting from the expansion serves to cool down the compressed air in the heat exchanger.
During this process, the refrigerant evaporates. The low-pressure gas is resupplied to the compressor, where it is
compressed again.
Operation in cycling mode (Energy Saving, ESS=YES – see section 8.12.7) – The DMC51 electronic controller
constantly monitors the temperature of the DewPoint. In low load conditions, the temperature of the DewPoint tends to
fall close to the freezing point, at this point the DMC51 controls the switching off of the compressor.
The compressor will be started again when the DewPoint temperature rises above a target value. To avoid an
excessive number of cycles, DMC51 keeps the compressor on for a minimum time (about 6 minutes) within which, if
necessary, will activate a solenoid valve EVH that enables the operation of the hot gas by-pass valve. In this way the
compressor cannot make more than 10 cycles per hour. The solenoid valve EVL and the check valve CHV (where
installed) help to extend the off time of the compressor and avoid the immediate balancing of high and low pressures of
the refrigerant circuit. The solenoid valve EVL is activated before the compressor to balance the pressures and is kept
active for the entire time during which the compressor is on.
With these dryers, the energy consumption will be adjusted closely proportional to the thermal load applied to the dryer
itself, allowing considerable energy savings in the majority of applications.
Operation in hot gas by-pass mode (NO Energy Saving, ESS=NO – see section 8.12.7) – The DMC51 electronic
controller constantly keep activated the compressor, the solenoid valve EVH and the solenoid valve EVL. In cases of a
reduced compressed-air load, the excess refrigerant is bypassed automatically to the compressor via the hot gas
bypass valve.

Technical description
iDRY iRDP CT 20-500 15
8.3 Flow chart
13
1
1c
T1
1b
1a
10
6
9M
8
DGF0129
21
12.1
36
86
11
87
82
7
T2
12.2
25
P<
2 4
P>
5
PV
1 Aluminium heat exchanger module 10 Filter dryer
a – Air/air heat exchanger 11 Capillary tube
b – Air/refrigerant heat exchanger 12.1 T1 temperature sensor (dew point)
c – Condensate separator 12.2 T2 temperature sensor (compressor discharge)
(iRDP CT 125-500)
2 Refrigerant pressure switch LPS (P<)
(iRDP CT 300-500 and iRDP CT 200-500 3phase) 13 Condensate drain service valve
4 Refrigerant pressure switch HPS (P>)
(iRDP CT 300-500 and iRDP CT 200-500 3phase) 21 iMAT condensate drain
5 Refrigerant fan pressure switch PV 25 Compressor crankcase heater (iRDP CT 200-
500 3phase)
6 Refrigerating compressor 36 Suction refrigerant separator
7 Hot-gas bypass valve 82 Check valve CHV
8 Condenser 86 Liquid solenoid valve EVL
9 Condenser fan 87 Hot gas solenoid valve EVH
Compressed-air flow direction Refrigerant gas flow direction

Technical description
16 iDRY iRDP CT 20-500
8.4 Refrigerating compressor
The employed refrigerating compressors are constructed by leading manufacturers. The hermetically sealed
construction is absolutely gastight. The integrated safeguard protects the compressor against overheating and excess
current. The protection is automatically reset as soon as the nominal conditions are reached again.
8.5 Condenser
The condenser is the component in which the gas coming from the compressor is cooled down, condensed and
liquefied. Under no circumstances must the temperature of the ambient air exceed the nominal values. It is also
important that the condenser unit is kept free from dust and other impurities.
8.6 Filter dryer
Despite controlled vacuuming, traces of moisture can accumulate in the refrigeration cycle. The filter dryer serves to
absorb this moisture and to bond it.
8.7 Capillary tube
The capillary tube is a copper tube with a reduced diameter which is located between the condenser and the
evaporator, serving as a restrictor to reduce the pressure of the refrigerant. The pressure reduction serves to reach an
optimum temperature inside of the evaporator. The lower the outlet pressure at the capillary tube, the lower the
evaporation temperature.
The length and the inner diameter of the capillary tube are exactly dimensioned to ensure the performance of the
dryer. Settings or maintenance works are not required.
8.8 Aluminium heat exchanger
The heat exchanger module consists of an air/air heat exchanger, an air/refrigerant heat exchanger, and of a high-
performance separator. The compressed air flows top-down through the heat exchanger. The large cross-sections of
the flow passages cause low flow rates and low compressed-air losses. In the air/air heat exchanger, the heat
exchange is effected in a reverse current. This guarantees maximum heat transfer. The heat transfer in the
air/refrigerant heat exchanger also takes place in a reverse current. This allows full evaporation of the refrigerant. The
high-performance separator ensures almost complete separation of the condensate. Maintenance of the high-
performance separator is not required.

Technical description
iDRY iRDP CT 20-500 17
8.9 Hot-gas bypass valve
At partial load, the valve directly returns a part of the hot gas to the suction line of the refrigerating compressor. The
evaporation temperature and the evaporation pressure remain constant.
ADJUSTMENT
The hot gas by-pass valve is adjusted during the manufacturing testing phase.
As a rule no adjustment is required; anyway if it is necessary the operation
must be carried out by an experienced refrigerating engineer.
WARNING
the use of ¼” Schrader service valves must be justified by a real malfunction
of the refrigerating system. Each time a pressure gauge is connected, a part
of refrigerant is exhausted.
Without compressed air flow through the dryer, rotate the adjusting screw
(position A on the drawing) until the following value is reached:
Hot gas setting :
R134.a pressure 31.9 psig (+ 1.45 / -0 psi) [2.2 barg (+0.1 / -0 bar)]
R407C pressure 68.2 psig (+1.45 / -0 psi) [4.7 barg (+0.1 / -0 bar)]
A
4 mm
5/32 in.
+
-
VLY0001
8.10 Refrigerant pressure switches LPS – HPS – PV
To ensure the operational reliability and the protection of the dryer, a series of pressure switches are installed in the
gas cycle.
LPS : Low-pressure guard on the suction side of the compressor, which is triggered when the pressure drops below
the predetermined value. The values are reset automatically as soon as the nominal conditions are re-
established.
Calibrated pressure : R 134.a Stop 10.2 psig (0.7 barg) - Restart 24.7 psig (1.7 barg)
R 407 C Stop 24.7 psig (1.7 barg) - Restart 39.2 psig (2.7 barg)
HPS : The high-pressure control unit on the discharge side of the compressor is activated when the pressure
exceeds the predetermined value. It has a manual reset button on the control itself.
Calibrated pressure : R 134.a Stop 290 psig (20 barg) - Manual reset P<203 psi (P<14 bar)
R 407 C Stop 435 psig (30 barg) - Manual reset P<334 psi (P<23 bar)
PV : Fan control pressure switch which is installed on the discharge side of the compressor. It keeps the
condensation temperature and pressure constantly in the range of the preadjusted limit values
Calibrated pressure : R 134.a Start 160 psig (+7.25 / -0 psi) [11 barg (+0.5 / -0 bar)]
Stop 116 psig (+0 / -7.25 psi) [8 barg (+0 / -0.5 bar)]
R 407 C Start 261 psig (+7.25 / -0 psi) [18 barg (+0.5 / -0 bar)]
Stop 203 psig (+0 / -7.25 psi) [14 barg (+0 / -0.5 bar)]
8.11 Compressor crankcase heater (iRDP CT 200-500 3phase)
At low temperatures, the oil can more easily intermix with the refrigerant gas. When the compressor starts, oil can be
drawn into the refrigeration cycle, leading to "hydraulic shocks".
To prevent this, a resistance heater is installed in the suction side of the compressor. When the system is connected
with the electric mains and the compressor is idle, the heater will keep the oil at the correct temperature.
This heater is controlled via a temperature switch which prevents the overheating of the oil.
Note: The heater must be connected to the mains at least a few hours prior to the start-up of the refrigerating
compressor.

Technical description
18 iDRY iRDP CT 20-500
8.12 DMC 51 electronics (control unit compressed-air dryer)
Set
PQS0076
DISPLAY
reset
K
Led - temperature in °C
Led - temperature in °F
Led - compressor ON
Led – Alarm
Led - service warning
Set Button – access configuration menu /
Discharge temp.
Button – decrease / service
Button – increase / % energy saved
The DMC51 controls all the operations, alarms and dryer operation set-up.
8.12.1 Switching the dryer on
Connect the dryer to the electric mains and switch it on via the ON/OFF switch (pos. 1 Section 8.1).
During normal operation, the display shows the dew point temperature.
8.12.2 Switching the dryer off
Switch the device off via the ON/OFF switch (pos. 1 Section 8.1).
8.12.3 Indication of the operating parameters
During normal operation, the display shows the dew point temperature (in °C or °F).
Led shows that the compressor is ON.
Press the Set button and keep it pressed to display the compressor discharge temperature (probe T2 if installed).
Press the button and keep it pressed to display the hours remaining until the next maintenance.
Press the Set + buttons simultaneously and keep them pressed to display the total number of operating
hours of the dryer (ie when dryer is powered)
Press the button and keep it pressed to display the % of energy saved.
Note: The temperatures are indicated in °C or °F (LED or is on).
The total operating hours and the hours until the next maintenance are indicated in the field 0...999 hours,
and in thousand hours from 1.0 hours onwards (example: when the display shows 35, this means 35 hours
and when the display shows 3.5, this means 3,500 hours).
The % of energy saved is calculated considering the running hours of the compressor against the operating
hours of the dryer (example: during 10 hours of powered dryer, compressor has ran for 4 hours, display
shows 60% of energy saved).

Technical description
iDRY iRDP CT 20-500 19
8.12.4 Indication of a Service Warning
A service warning is an exceptional event and requires the attention of the operator/service technician. The dryer will
not be stopped.
When a service warning is active, the Led flashes.
When a service warning is no longer active but not reset yet (so it has been stored) Led is continuously on.
In both cases the display shows the dew point temperature and the service warnings which are active or which are no
longer active but not yet reset.
Service warnings are NOT automatically reset.
To RESET the service warning, the Led must be continuously on (not flashing), keep pressed simultaneously
Set + buttons for three seconds. Only the stored service warning will be reset. Service warnings which
are still active continue to be indicated by the Led flashing.
NOTE: the operator/service technician must check the dryer and eliminate the problem that caused the service
warning.
Service warning Description
HdP – High dew point: dew point too high, higher than the adjusted HdS value
LdP – Low dew point: dew point too low
Setting T1< -1°C (30°F) delay five minutes / reset T1> -0.5°C (31°F)
SrV - Service: maintenance service time expired SrV
8.12.5 Indication of an Alarm
An alarm is an exceptional event which, to avert damage from to the machine and the operator, always leads to the
dryer stop.
When an alarm is active, the LED flashes.
When an alarm is no longer active but not reset yet (so it has been stored) Led is continuously on (in any case,
the dryer remains OFF).
In both cases the display shows and the alarms which are active or which are no longer active but not yet reset.
Alarms are NOT automatically reset.
To RESET the alarm, the Led must be continuously on (not flashing), keep pressed simultaneously Set +
buttons for three seconds. Only the stored alarm will be reset. Alarms which are still active continue to be
indicated by the Led flashing.
The dryer will start automatically subsequent to the reset of the alarms.
NOTE: the operator/service technician must check the dryer and eliminate the problem that caused the alarm.
Alarm Description
LP – Low pressure: the refrigerant low-pressure switch LPS has tripped.
Hdt – High outlet temperature: compressor outlet temperature outside the safety limit
Setting T2> 110°C (230°F) delay one minute / reset T2< 90°C (194°F)
ICE - ICE / Icing: Temperature in the exchanger (probe T1) is too low and leads to icing
of the condensate.
Setting T1< -2°C (28°F) delay one minute / reset T1> 0°C (32°F)
toC – Too many Cycles : compressor has been cycled On/OFF unusually too often
(stopped more than 5 times before reaching its minimum ON time)
PF1 – Probe 1 failure: failure probe T1
PF2 – Probe 2 failure: failure probe T2

Technical description
20 iDRY iRDP CT 20-500
8.12.6 Operation of the Service Warning / Alarm signal
The DMC 51 is equipped with a 12Vdc signal (max 15 mA) to indicate service warning or alarm conditions.
Dryer is switched on, no service warning and no alarm (active and not yet reset) are
indicated.
Dryer is off or a service warning or an alarm (active and not yet reset) is indicated.
8.12.7 How to change operating parameters – SETUP menu
The setup menu can be used to change the dryer’s operating parameters.
Only qualified personnel must be allowed to access to the setup menu. The manufacturer is
not responsible for malfunctioning or failure due to modification to the operating parameters.
With dryer ON simultaneously press buttons Set + for at least 5 seconds to enter the setup menu.
Access to the menu is confirmed by message on the display (first parameter of menu).
Keep Set pressed to display the value of the selected parameter and use arrows and to change
the value. Release the button Set to confirm the value and skip to following parameter.
Press + to exit setup menu (if no button is pressed after 30 seconds the menu is exited
automatically).
ID Description Limits Resolution
Standard
setup
HdS - High DewPoint Setting : service warning threshold for
a high DewPoint (the service warning disappears when the
temperature drop 0.5°C / 1°F below set point)
0.0…25.0 °C
or
32 … 77 °F
0.5 °C
or
1 °F
20
or
68
Hdd - High DewPoint Delay : high DewPoint service
warning enable delay 00 … 20
minutes 1 min 15
SrV - Service Setting : setting of service warning timer.
0.0 = service warning timer disabled.
0.0 … 9.0
(x 1000)
hours
0.1
(x1000) hours 8.0
SCL - Scale: display scale of temperatures. °C … °F - °C or °F
ESS – Energy Saving Set: selection if dryer run in energy
saving cycle.
YES = Energy saving mode is active (cycling mode).
nO = Energy saving mode is not active (Hot Gas by-pass
sytem)
YES…nO - YES
8.13 Electronically level-controlled iMAT condensate drain
The electronically level-controlled iMAT condensate drain boasts a special condensate management which ensures
that condensate is discharged safely and without an unnecessary loss of compressed air. This drain has a condensate
collection container in which a capacitive sensor continuously monitors the liquid level. As soon as the switching level
is reached, the capacitive sensor transmits a signal to the electronic control and a membrane solenoid valve opens to
discharge the condensate. The iMAT closes before compressed air emerges.
Note!
These iMAT condensate drains were designed in particular for the operation in a iDRY iRDP CT
refrigeration dryer. The installation in other compressed-air processing systems or the replacement with
another drain brand can lead to malfunction. The maximum operating pressure (see type plate) must not
be exceeded!
Ensure that the upstream valve is open when the dryer starts operation.
To obtain detailed information regarding drain functions, troubleshooting, maintenance and spare
parts, please read the installation and operating instructions of the iMAT condensate drain.