Rehau DHU C 24 L Guide

DHU C 24 L
EN Dehumidifier
Instructions for installation, commissioning and maintenance
ES Deshumidificador
Instrucciones de montaje, puesta en marcha y mantenimiento
FR Déshumidificateur
Instructions de montage, de mise en service et de maintenance
IT Deumidificatore
Istruzioni di montaggio, messa in funzione e manutenzione
PT Desumidificador
Instruções para montagem, colocação em funcionamento e manutenção

Contents / Contenido /
Table des matières /
Indice / Índice
Instructions for installation, commissioning and maintenance 3
Instrucciones de montaje, puesta en marcha ymantenimiento 19
Instructions de montage, de mise en service et de maintenance 35
Istruzioni di montaggio, messa in funzione e manutenzione 51
Instruções para montagem, colocação em funcionamento e manutenção 67

Instructions for installation, commissioning and maintenance
Dehumidifier DHU C 24 L

Contents
01 Information and safety instructions 05
02 Product description 07
02.01 General 07
02.02 Components 07
02.03 Technical data 08
02.04 Electrical diagram 09
03 Installation instructions 10
03.01 Packaging and scope of supply 10
03.02 Installing the unit 10
03.03 Air duct connection 12
03.04 Water-side connections 12
03.05 Power supply and control connection 13
04 Commissioning and operation 15
04.01 Display and operation 15
04.02 Commissioning 16
04.03 Operation and maintenance 17
04.04 Spare parts 18
04.05 Disassembly and disposal 18
EN
04

01 Information and safety instructions
About these instructions
Read these instructions thoroughly and completely
before you start working with the dehumidifier.
Keep this document for the entire lifetime of the
machine and pass it on to subsequent users. To view
and download the current version of these and other
guides, see
www.rehau.com/TI
Electrical voltage! Danger to life!
Safety instructions
Legal notice
Important information
Further information can be found on the
internet, for example
Security
All safety instructions in these instructions must be
observed in order to avoid accidents with personal
damage or property damage.
This document has been written for authorised and
qualified personnel.
The product must be installed and operated in strict
accordance with the relevant information and
specifications in this document. The manufacturer
accepts no responsibility for modifications made to
the product by the user.
Failure to comply with the regulations and
specifications contained in these instructions will
result in the immediate expiry of the warranty. It is in
your interest to contact the manufacturer immediately
if discrepancies are found or uncertainties exist.
Attention: dangerto life!
▪The electrical installation may only be carried out
by an electrically skilled person. The electrical
installation must follow the applicable national
standards and guidelines as well as any specific
requirements of your local energy supplier.
▪Interventions or modifications to the unit using
tools may only be carried out by qualified service
personnel.
▪Installation of the unit must be carried out by
qualified personnel and in accordance with the
applicable safety standards.
▪This unit is not intended to be used by persons
(including children) with restricted physical, sensory
or mental skills or who lack experience or
knowledge.
▪Ensure that children do not play with this product.
▪This machine has been designed and manufactured
according to the strictest safety regulations.
Nevertheless, no sharp objects (screwdrivers,
needles or similar) may be inserted in the grilles or
other unit openings.
▪The dehumidifier must be connected to a power
supply that is adequately protected by a residual
current circuit breaker. An electrical disconnect
must be provided near the unit to allow the user to
intervene in safe conditions. This disconnect must
always be used to eliminate hazards during
maintenance (electric shock, burns, automatic
restart, moving parts and remote control).
▪The unit must always be connected to the earth
cable of the electrical system. Failure to comply with
this regulation, as with all electrical equipment, is a
cause of danger for which the manufacturer accepts
no liability.
▪The machine must be installed in accordance with
the energy supplier’s local installation regulations.
▪All maintenance and cleaning work on the unit must
be carried out in a de-energised state. Never remove
or open any part of the unit without first
disconnecting the power supply.
05
EN
05

Installation situation
▪The unit must be placed in a clean and dry place,
protected from splashing water and drops of water.
▪This unit is intended for indoor use in buildings.
▪The machine must be installed in compliance with
the required dimensions and minimum clearances.
▪For this unit, a slope to the condensation drain of at
least 5mm (approx. 1%) must be maintained
between the ends of the machine.
▪Make sure that possible ventilation grilles of the
supply or exhaust air are not covered or obstructed:
The unit may otherwise be damaged and cause
hazards.
Cleaning
Clean the filter regularly: Cleaning must be carried out
at least every two months. When used in very dusty
environments, cleaning must be carried out more
frequently. Information on maintenance and cleaning
procedures can be found further towards the end of
these instructions.
If the filter is dirty, the air comes out hotter than
normal, which can damage the appliance and reduce
the formation of condensation.
Personal protective equipment
Use the following personal protective equipment when
operating and carrying out maintenance on the
machine:
Persons carrying out maintenance work or working
with the unit should wear antistatic safety shoes with
non-slip soles.
Gloves: The use of suitable gloves is required for
cleaning and maintenance work.
Safety glasses must be worn as eye protection during
cleaning and maintenance work.
Safety sign
Every eort has been made in the design and
manufacture of the machine to eliminate risks.
The system is marked with the following safety signs,
which must be observed:
General danger
Danger of electric shock
General information
These instructions and the documents supplied are
intended to enable the installer to correctly install and
commission the machine without endangering
persons or causing damage to the device.
They also enable the subsequent user to clean the
filter safely and correctly.
We recommend that the following be observed for all
activities related to the operation and maintenance of
the machine:
▪Activities to be carried out only by suitably qualified
persons who must apply safe working practices and
use the appropriate personal protective equipment
for the task in hand.
▪Activities to be carried out only by appropriately
instructed and trained persons who have read and
understood these instructions, the technical
information and the safety instructions.
▪Access to the machine must be denied to persons
who are not appropriately trained or competent.
CE conformity
The machine described in these instructions complies
with the essential requirements of the following
European directives:
▪Electrical safety for low-voltage applications
2014/35/EU,
▪Electromagnetic compatibility 2014/30/EU,
▪Pressure equipment 2014/68/EU,
▪RoHS directive 2011/65/EU.
The following harmonised standards were applied
▪DIN EN 60335-2-40: 2014-01
▪DIN EN 60335-1: 2020-08
▪DIN EN 55014-1/A11: 2021-03
▪DIN EN 55014-2: 2017-03
▪DIN EN 378-2: 2018-04
▪DIN EN IEC 63000: 2019-05
EN
06

02 Product description
02.01 General
In regions with high temperatures and high humidity,
there is a risk of condensation water forming on the
cooling surfaces of a embedded radiant cooling
system. In addition, too much humidity can have
negative eects on thermal comfort. For this reason,
it makes sense to reduce the humidity in rooms.
The DHU C 24 L dehumidifier was specially developed
for use in combination with REHAU embedded radiant
cooling system. The external control of the unit is
taken care of using the REHAU control system
NEA SMART 2.0.
02.02 Components
The mode of this dehumidifier is the Air dehumidifica-
tion. The air is dehumidified, whereby the temperature
at the inlet and outlet is almost the same.
The dehumidifier consists of an air filter, a refrigerant
circuit, a water circuit that can be connected to the
cooling circuit of the embedded radiant cooling
system, a fan and an electronic unit.
The air filter ensures that the amount of dirt and dust
entering the machine is reduced. It must be cleaned
regularly. Please refer to chapter 04.03.
The water circuit, which can be connected to a
hydraulic circuit of the embedded radiant cooling
system, has two fin coil heat exchangers with air flow,
the pre-cooler and the post-cooler.
The refrigerant circuit consists of the following
components:
A fin coil heat exchanger with air flow where the air
is dehumidified, is the evaporator of the refrigerant
circuit. The required energy is extracted from the
environment. This is the so-called cold area.
The compressor of the circuit is a hermetic recipro-
cating piston compressor for building up the pressure
of the refrigerant.
Another fin coil heat exchanger with air flow is the
condenser of the refrigerant circuit, depending on the
operating mode. Heat is released during this process.
This is the so-called warm area.
For monitoring and controlling the machine, there is an
electronic unit with microprocessor and display.
The microprocessor controls the defrosting phases
as well as switching on and o of the compressor and
the fan.
EN
07

02.03 Technical data
Power supply
 V AC,  Hz
Electrical power
)
 W
Maximum current consumption
, A
Switch-on current (LRA)
, A
Air flow rate at fan speed Min () and  Pa counterpressure
 m/h
Maximum counterpressure at  m/h (fan speed Min () / Med () / Max ())
 Pa /  Pa /  Pa
Refrigerant Ra
 g
Operating range – temperature
 –  °C
Operating range – relative humidity
 –  %
Dehumidification capacity
), )
 l/d
Water-side capacity
)
 W
Water flow rate
 l/h
Pressure loss in the water circuit at  l/h
 kPa
Dimensions (L x H x W)
 mm x  mm x  mm
Weight with filled water circuit
, kg
1) Air: 25 °C, 65 % relative humidity / water: 16 °C, 180 l/h / fan speed: Min (3) / counter-pressure: 25 Pa
2) Dehumidification capacity measured according to DIN EN 810 and DIN EN 1397
164
12573
134
771
108
683
750
447
80
22
80
693
Ø10
260
238
4
3
2
1
5
6
7
8
814
1
Vent valve
2
Condensation drain 16mm
3
Water Return 3/8″ M
4
Water Supply 3/8″ M
5
Cable bushing
6
Electronics box with display
7
Air outlet
8
Air inlet with air filter
EN
08

02.04 Electrical diagram
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Voltage and power supply
2
Input signals (Digital 5 Vcc)
▪DH Hygrostat– starts dehumidification
▪VENT starts ventilation
3
Output signal (optional, 230VAC 1AMax)
ZONE VALVE water circuit actuator
4
On-site connections
5
Compressor
6
Fan
7
Autotransformer
Note that fan speeds 4, 5 and 6 must not be used.
This could damage the unit.
8
Printed circuit board
9
Display
EN
09

03 Installation instructions
The work must be carried out by qualified personnel.
03.01 Packaging and scope of supply
Remove the packaging carefully, taking care not to
damage the unit.
Read these installation instructions thoroughly and
completely before you start working with the product.
Keep the installation instructions for the entire service
life of the machine and pass them on to subsequent
users.
Keep the packaging material out of the reach of
children and animals as this can lead to dangerous
situations.
Dispose of the packaging products (wood, plastic,
cardboard or polystyrene/Styrofoam) at specialised
collection points or recycling centres in accordance
with local regulations.
All components of the unit are assembled and tested
at the factory. On receipt of the machine, it must be
carefully inspected immediately for transport damage
and missing parts.
03.02 Installing the unit
The dehumidifier is to be installed on the ceiling. To do
this, the unit must be fastened using the four perforated
side lugs. Approved dowels and fasteners suitable for the
application and load case must be used for this fastening.
Installation situation
▪The unit must be installed in a clean and dry place
protected from splashing water and drops of water.
▪This unit is intended for indoor use in buildings.
▪For this unit, a slope to the condensation drain of at
least 5mm (approx. 1%) must be maintained
between the ends of the machine.
Observe correct fastening as well as suicient
dimensioning of the dowels and fasteners on the
ceiling and on the unit.
The following should be taken into consideration:
▪The weight of the dehumidifier
▪The material and condition of the ceiling
▪Possible vibrations of the dehumidifier
The ceiling must be suitable to support the weight of
the unit of 44.8 kg when filled.
▪Be aware of the weight and sharp corners and
edges of the unit and wear suitable protective
clothing.
▪Due to the weight, use of a construction site lift is
recommended. In addition, the installation should
be carried out by at least two people.
Check that the connections of the dowels and
fasteners on the ceiling and on the unit cannot
accidentally come loose.
The use of sound-decoupled connections is
recommended.
EN
10

Regular maintenance and cleaning
The machine can be inspected by removing the side
panels on the left and right. It is therefore necessary to
ensure access from both sides so as to be able to reach
all parts of the unit, such as the fan, compressor and
the electronics box. In addition, access must be enabled
on the intake side of the unit for installation and removal
of the filter.
Before carrying out any maintenance work on the unit,
it must be de-energised.
For normal, regular cleaning and maintenance of the
dehumidifier, integration of at least two inspection
flaps in the ceiling soit is therefore recommended as
shown in the illustration. This allows the filter on the
intake side to be installed and removed and the
hydraulic connections, the condensation drain, the
water circuit vent valve and the electronic unit with
display to be accessed.
Dismantling the unit
It may be necessary to dismantle the unit if, for
example, irreversible damage has occurred on site.
To avoid costs in this case, a removable ceiling section
around the dehumidifier is recommended.
This means an area of the ceiling soit that can be
removed with little eort without damaging the ceiling
structure. The minimum distances and possible
dimensioning of this removable ceiling area are
described in the figure.
Functional testing of the unit is strongly recommended
before closing the soit.
1
Two inspection flaps in the ceiling soit
2
Removable ceiling section
600
1863
650
50
752
100
200
912
450
50
1502
100
600
50
1
1
2
EN
11

03.03 Air duct connection
Dimensions
Width
mm
Height
mm
When connecting to air ducts, flexible vibration
dampers must be interposed to prevent the
transmission of vibrations generated by the machine.
It is advisable to install sound absorbers on the
ventilation pipes, especially if the unit is installed in
a room in which people sleep.
Use suitable screws to mount the air duct. Seal the
connection points suiciently with suitable materials
so that no uncontrolled air leakage can occur.
The unit front with the exhaust air opening is attached
to the unit body with screws and can be dismantled to
use the REHAU attachment for connecting ventilation
pipes.
The air volume flow is 260 m/h at a counterpressure
through the air duct of 25 Pa at fan speed Min (3).
It should be noted that at this fan speed, the
counterpressure of the air duct does not exceed the
maximum level of 35 Pa, which corresponds to an air
volume flow of 220 m/h. If a higher pressure loss of
the air duct cannot be avoided, the fan speed can be
changed to Med (2) or Max (1) by reconnecting the
cable on the autotransformer located in the electronics
box (see chapter 02.04).
Note that fan speeds 4, 5 and 6 must not be used.
This could damage the unit.
1
Unit front with exhaust air opening for the air duct
connection
03.04 Water-side connections
Pipe dimension
Connection
Cooling circuit
Supply/Return
d
in ≥ mm
/″ M
Condensation
d
in ≥ mm
mm
Water circuit
Provision of a water filter at the inlet of the
dehumidifier is recommended in order to protect the
water circuits of the unit.
Use REHAU pipe RAUTHERM-S or RAUTITAN for the
hydraulic connections to the dehumidifier (feed and
return) and observe the applicable local regulations.
Use suitable connection technology and suitable
sealing material so that no water can escape in an
uncontrolled fashion at the unit connection.
Carefully vent the water circuit using the relevant valve
on the unit as shown in the illustration. To avoid the
formation of condensation on metallic connections,
these must be insulated.
EN
12

1
Vent valve
2
Condensation drain 16mm
3
Water Return 3/8″ M
4
Water Supply 3/8″ M
For the correct connection to the manifold of the
embedded radiant cooling system and the setting of
the correct flow rate, please observe the relevant
installation instructions and the applicable local
regulations. The nominal flow rate of the water circuit
of this dehumidifier is 180 l/h.
Condensation drain
To prevent the formation of bad odours from the waste
water and to ensure the drainage of the condensate,
it is important to connect the condensation drain to a
siphon. To facilitate cleaning, mount the siphon in an
easily accessible place.
03.05 Power supply and control connection
Dimension
Connection
Power supply
minimum  x .mm, rigid
Terminal
Attention: dangerto life!
▪The electrical installation may only be carried out
by an electrically skilled person. The electrical
installation must follow the applicable national
standards and guidelines as well as any specific
requirements of your local energy supplier.
▪Before carrying out any work on the electrical
components, make sure that the power supply is
disconnected.
▪The main power supply must be protected with
a residual-current circuit breaker.
▪An electrical disconnect must be provided near the
unit to disconnect the power supply before
maintenance and cleaning.
▪Care must be taken to ensure that the regulations
for electrical installations and equipment are fully
complied with.
▪Check to ensure the supply voltage corresponds to
the rated data of the unit (voltage, frequency) on the
type plate of the machine.
▪Earthing is mandatory and must be connected first
during installation.
Loosen the two screws of the electronics box and
carefully remove the cover with the display.
13
4
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EN
13

Connect the power supply (230V, AC, single-phase,
50Hz) to the terminals phase L, neutral N and protec-
tive earth PE of the machine as shown in the illustra-
tion.
Potential-free contacts are provided for the control
inputs of the machine. Connect the corresponding
wires to the terminal as shown in the illustration.
There are two dierent input signals:
▪DH: Request for air dehumidification
▪VENT: Request for continuous fan operation
The REHAU control system NEA SMART 2.0 can be
used to control the dehumidifier. For correct connection
and correct use, observe the relevant technical
information and the locally applicable regulations.
If required, the REHAU actuator UNI 230V, which is
assigned to the water circuit of the dehumidifier, can
be connected to the terminals of the ZONE VALVE
output signal. When using an on-site actuator, please
ensure that the nominal data of this actuator match
the output signal 230VAC 1AMax of the
dehumidifier.
Use separate cables for the power supply, the input
signals and the output signal and the cable glands
provided at the factory for this purpose. If three cable
glands are required for this, an additional cable gland
must be installed on site at the location of the cable
grommet. The factory-fitted cable glands are suitable
for cables with an outer diameter of 6 – 12 mm.
Before using the unit, the electronics box cover must
be properly closed again.
1
Voltage and power supply
2
Input signals (Digital 5 Vcc)
▪DH Hygrostat – starts dehumidification
▪VENT starts ventilation
3
Output signal (optional, 230 V AC 1 A Max)
ZONE VALVE water circuit actuator
4
On-site connections
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14

04 Commissioning and operation
04.01 Display and operation
Displays
Connected power supply
Two blue stripes on the display indicate
when the power supply is present. If there
is no request, the unit is in STAND BY
mode.
Dehumidification active
This orange LED indicates that
dehumidification is active. If the symbol is
not illuminated, no dehumidification is
being requested at that moment.
Continuous ventilation active
This orange LED lights up when the
continuous ventilation request is
activated. Otherwise there is no request.
Compressor running
If this green LED lights up continuously,
the compressor is in operation.
When this LED flashes, the compressor is
in Pause mode. This mode is active during
the switch-on phase and during the
automatic defrosting phase controlled by
the microprocessor.
Buttons
Set buttons
These buttons are only
necessary for configuration
and are not relevant for
operation or proper
maintenance.
HOURS
When this button is pressed, the
operating hours of the compressor are
displayed.
– –
– –
– –
– –
– –
– –
– –
EN
15

04.02 Commissioning
Before powering the dehumidifier for the first time by
switching the electrical disconnect, check the
following:
▪Have the safety instructions and the locally
applicable regulations been observed?
▪Is the dehumidifier properly and securely attached
to the ceiling?
▪Is the air duct correctly dimensioned, properly
installed and adequately sealed?
▪Have the hydraulic and electrical connections been
made according to these instructions and in
compliance with local regulations?
▪Have the hydraulic and electrical connections been
made properly?
▪Are the hydraulic connections of the water circuit
and the condensation drain properly sealed?
▪Is the water circuit filled and properly vented?
▪Is the dehumidifier properly earthed?
▪Does the supply voltage match the value specified
in the technical data?
The supply voltage must correspond to the
specifications on the type plate with ±10 %
tolerance.
▪Are all cover plates in the correct position and
adequately secured with the appropriate fixing
screws?
▪Is the cover of the electronics box properly inserted
and secured with the appropriate screws?
After the device has been properly installed, the first
start-up may only be carried out after at least 2 hours.
If the water circuit is not filled, not properly vented or
there is no suicient water supply available in the set
temperature range, the function of the machine may
be impaired.
As soon as the unit is supplied with voltage, it is in
STAND BY mode and the display shows two blue
stripes.
Now the input signals of the dehumidifier can be set
using the connected NEA SMART 2.0 control system.
After an input signal has been set, the fan starts right
away.
The input signal dehumidification (DH) additionally
activates the output signal ZONE VALVE and the
compressor starts with a time delay.
For correct wiring and configuration of the
NEA SMART 2.0 control system, refer to the relevant
technical information.
EN
16

04.03 Operation and maintenance
During operation, a suicient water supply must be
available in the set temperature range.
Ventilation grilles for supply and exhaust air must not
be adjusted or covered during operation, ensuring the
air can flow at all times.
Before starting maintenance work, check that the
dehumidifier is disconnected from the power supply.
Maintenance may only be carried out by appropriately
instructed and trained persons.
Regular maintenance of the machine consists of
cleaning the air filter, which can be removed. Cleaning
of the filter is recommended every two months. In
dusty environments or when the unit is used
intensively, maintenance may also be necessary more
frequently.
Access to the filter must always be possible so that
maintenance work can be carried out.
Regularly check the condition and function of the
dehumidifier’s attachments to the building structure or
supporting elements.
Check regularly to ensure the siphon is not blocked
and that the condensation can drain o.
Cleaning steps
1
1After gaining access to the intake side of the
dehumidifier, lift the air filter slightly using the handles.
1
2
2
2Pull the lower section of the air filter slightly
forwards and then pull it down and o.
3
3Clean the air filter under a jet of water in the
opposite direction to the normal air flow direction
and then let it dry.
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1
2
4
4Place the top edge of the clean and dry air filter at
a slight angle on the unit and press the lower section
against the unit.
5
5Push the air filter down slightly so that it is firmly
and properly mounted again.
Do not restart the dehumidifier until the clean and dry
filter has been firmly and properly refitted.
04.04 Spare parts
We recommend the use of original spare parts.
If required, please get in touch with your REHAU
contact person.
04.05 Disassembly and disposal
The machine is designed and built for continuous
operation. The service life of some important
components, such as the fan and the compressor,
depends on the maintenance they receive.
Before disassembly, the unit must be disconnected.
Note that water may be present in the system.
Disassembly may only be carried out by qualified
personnel using suitable protective equipment. Due to
the weight of the unit, a construction site lift should be
used, and disassembly should be carried out by at
least two people.
To prevent injury or damage during subsequent
transport, the unit must be provided with suitable
packaging material and adequate transport securing.
The unit contains environmentally hazardous
substances and components (electronic components,
refrigerant gas and oils). The appliance must be taken
to specialised companies for the collection and
disposal of appliances containing hazardous
substances. The refrigerant R134a and lubricating
oil contained in the circuit must be recovered in
accordance with the regulations in force in your
country.
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Deshumidificador DHU C 24 L
Instrucciones de montaje, puesta en marcha y mantenimiento

Contenido
01 Informaciones e indicaciones de seguridad 21
02 Descripción del producto 23
02.01 Aspectos generales 23
02.02 Componentes 23
02.03 Datos técnicos 24
02.04 Esquema eléctrico 25
03 Instrucciones de montaje 26
03.01 Embalaje y volumen de suministro 26
03.02 Montaje del aparato 26
03.03 Conexión al conducto de aire 28
03.04 Conexiones en el lado del agua 28
03.05 Acometida eléctrica y conexión del control 29
04 Puesta en marcha y operación 31
04.01 Display y manejo 31
04.02 Primera puesta en marcha 32
04.03 Operación y mantenimiento 33
04.04 Recambios 34
04.05 Desmontaje y eliminación 34
20
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