Airflow Duplexvent Flexi DV1600 User manual

VENTILATION UNITS WITH
HEAT RECOVERY
DUPLEXVENT FLEXI
DV1600/2600
Installation, use and maintenance manual
80000074- Issue 1 6/11

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Dear customer,
Thank you for choosing our product and we hope that you will be fully satisfied.
This manual contains all necessary instructions, information, hints and recommendations for safe and correct equipment installation
and commissioning. Please read the manual carefully and follow the instructions contained herein.
Symbols explained
Items or sections marked with (or with a grey background) apply only to appliances manufactured in compliance with the
hygienic requirements of Regulation VDI 6022 (indicated on the identification plate, see following chapters).
Important notes
●Electrical connections, commissioning and adjustment of the appliance may only be carried out by qualified electrical
engineers.
●Before the installation and commissioning of the appliance carefully read the installation, use and maintenance
manual, the controller operation manual and, where applicable, the service documentation.
●The appliance and all its accessories must be installed and used in compliance with the design, technical conditions
specified by the manufacturer and applicable legislation and technical standards in effect.
●The appliance must not be installed and operated in an aggressive environment that could damage its external and
internal mechanical parts.
●Before putting the appliance into permanent operation an initial inspection report on the appliance´s power supply
must be provided.
Before putting the appliance into operation an approval test (see VDI2079 and DIN EN V 12599) of the entire HVAC
system of which the appliance forms part must be conducted. The test must include the examination of hygienic
requirements as per VDI 6022 and must be documented. The user must be able to present the approval test report at any
time. If the above requirements are not met, the manufacturer cannot ensure compliance with hygienic requirements.
The manufacturer is not liable for damage caused by unprofessional installation and operation that
is not in compliance with the operation and maintenance manual and general practices applied
during installation and operation of HVAC equipment and control systems.

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1. Content
1. Content ........................................................................................................................................................................................3
2. Safety instructions........................................................................................................................................................................4
2.1 General safety...............................................................................................................................................................................4
2.2 Operational safety.........................................................................................................................................................................4
3. Storage and transport...................................................................................................................................................................4
4. Description...................................................................................................................................................................................5
4.1 General .........................................................................................................................................................................................5
4.2 Intended use .................................................................................................................................................................................5
5. Installation....................................................................................................................................................................................5
5.1 Safety instructions.........................................................................................................................................................................5
5.2 Hygienic instructions for the appliance as per VDI 6022...............................................................................................................5
5.3 Identification of ports, connecting the HVAC duct..........................................................................................................................5
5.4 Installation steps............................................................................................................................................................................6
5.5 Adjusting the unit - turning ports e2 (SUP) / i2 (EHA)....................................................................................................................6
5.6 Connecting the condensate drain pipe..........................................................................................................................................6
5.7 Classification of air filters...............................................................................................................................................................7
5.8 Installing air filters..........................................................................................................................................................................7
5.9 Installation, connecting and filling of liquid manometers (optional accessory)...............................................................................8
5.10 Installation and connecting of the hot water air heater (optional accessory)...............................................................................8
5.11 Installation and connecting of the control set for the hot water air heater (optional accessory)...................................................8
5.12 Installation and connecting of shut-off dampers e1, i1 (optional accessory)................................................................................8
5.13 Installation of flexible flanges (optional accessory)......................................................................................................................9
5.14 Installation and connecting of the water chiller to the cooling source (optional accessory).........................................................9
5.15 Installation and connecting of the direct chiller (optional accessory)...........................................................................................9
5.16 Installation and connecting of the electric heater / pre-heater EPO-V (optional accessory)........................................................9
5.17 Installation and connecting of manostats to control constant flow rates and pressure (optional accessory)...............................9
6. Electrical connection, commissioning, description of controls......................................................................................................9
7. Hygienic instructions for the appliance as per VDI 6022..............................................................................................................9
7.1 General instructions ......................................................................................................................................................................9
7.2 Required qualifications of personnel as per the type of activity...................................................................................................10
a) Category B hygiene training of personnel..................................................................................................................................10
a) Category A hygiene training of personnel..................................................................................................................................10
8. Inspecting the appliance ............................................................................................................................................................10
8.1 Overview of inspections and measures to ensure compliance with hygiene requirements.........................................................10
9. Cleaning and maintenance ........................................................................................................................................................12
9.1 General .......................................................................................................................................................................................12
9.2 Cleaning the cabinet....................................................................................................................................................................12
9.3 Air filters, replacing filter cassettes..............................................................................................................................................12
9.4 Cleaning heat exchangers (heater / chiller).................................................................................................................................13
9.5 Cleaning the plastic heat recovery exchanger.............................................................................................................................13
9.6 Draining and inspection of the condensate collection tank (not included in delivery)..................................................................13
9.7 Other minor maintenance............................................................................................................................................................13
10. Failures and troubleshooting......................................................................................................................................................13
11. Repairs, spare parts...................................................................................................................................................................14
12. Visual appendix - manuals.........................................................................................................................................................15
12.1 Turning the fan..........................................................................................................................................................................15
12.2 Connecting the condensate drain outlet....................................................................................................................................16
12.3 Installing filters...........................................................................................................................................................................17
13. Warranty...................................................................................................................................................................................18

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2. Safety instructions
2.1 General safety
●Only adults sufficiently familiar with the operation and maintenance manual may operate the equipment.
●The user must not tamper with or modify any part of the equipment, particularly the power supply lines!
●Only professional service technicians with relevant qualifications may perform equipment repairs. Unprofessional repairs are
very risky and may result in loss of warranty.
●Before opening the equipment´s door for cleaning, filter replacement or general maintenance always make sure that the
equipment is disconnected from power supply and prevent its reconnection by another person.
●To prevent injuries caused by the fan impeller, a duct at least 2 metres long must always be connected to the fan discharge. The
duct must be fastened in such a way that it cannot be removed without tools.
●If the equipment has been out of operation for a prolonged period of time, extra care should be taken when putting it back into
operation.
2.2 Operational safety
●The indoor version of the unit is intended for a basic environment - ambient temperatures must be between +5°C and +55°C with
relative humidity up to 60 %. If the appliance is located elsewhere, its sufficient protection must be ensured.
●The appliance may be operated within the temperature range of ventilation air between -25°C and +40°C with relative exhaust
air humidity up to 95%, in an environment where there is no risk of fire or an explosion of flammable gases and fumes, and not
containing organic solvents or aggressive substances that might damage mechanical parts of the unit. If there is a danger of
such gases and fumes temporarily entering the duct system (e.g. during floor bonding, painting), the unit must be switched off
sufficiently in advance.
●In the event of a failure the appliance must be disconnected from power supply as soon as possible!
●The water chiller in all versions must be filled with an antifreeze solution with sufficient thermal resistance, or it must be drained
for the period during which outdoor temperature might fall below +5°C. We recommend draining water from the chiller with
pressurized air, not using a gravity flow!
●Appliances with hot water heaters
- Must be permanently connected to power supply to provide the anti-freeze protection of the hot water heater. In the case of
a prolonged power outage the heating medium must be drained from the hot water heater including the control set. We
recommend draining water from the heater with pressurised air, not using a gravity flow!
- It may only be operated if the heating system including the hot water heater and control set are filled with a heating medium
and air bleed; also applies to periods outside the heating season! In the case when the heating system including the hot
water heater and control set are not filled with a heating medium, the appliance must be drained of the remaining heating
medium, dried properly and disconnected from power supply.
3. Storage and transport
●The appliance may only be stored in dry, covered places with ambient temperatures between -25 °C and 55 °C in such a way
that its surfaces that are to be in contact with transported air remain protected against the weather and stay dry and clean.
●Packaging may not be removed until immediately before the installation of the appliance in its operating position. If that is not the
case, all parts must be checked for cleanliness before installation and thoroughly cleaned if necessary.
●The appliance must not contain any operational liquids (e.g. water in the hot water heater, water chiller etc.) during storage and
transport.
●The appliance may only be transported on handling blocks (included). During transportation the appliance must be protected
against mechanical damage and water penetration and all openings must be covered with protective covers.
●During transportation the appliance must be secured against falling. The mode of transport must also eliminate any falls of the
appliance or instances of the appliance getting loose.
Only permitted methods of handling

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4. Description
4.1 General
●DUPLEXVENT FLEXI series ventilation units with heat recovery are compact appliances containing in a single cabinet two
independently powered fans with flexible mounted motors, a highly efficient heat recovery exchanger assembled from thin-walled
plastic boards for the recovery of heat / cool, a by-pass damper, slide-out filters and drainage trays, and depending on
accessories selected an external heater, chiller, shut-off dampers, flexible flanges and a control system.
4.2 Intended use
●DUPLEXVENT FLEXI series ventilation units with heat recovery are intended for comfort ventilation and possibly hot-air heating
and cooling of flats, houses, small plants, workshops, schools, restaurants, cooking facilities and industrial halls with a basic
environment. If the appliance is used for different purposes or is not operated in compliance with instructions contained in the
operation and maintenance manual, the manufacturer is not liable for resulting damages.
5. Installation
5.1 Safety instructions
●During installation make sure no damage or deformation is caused to the case of the appliance (e.g. as a result of handling
operations).
●After setting the appliance in place check it for stability and secure it in this position.
●During handling and installation observe all rules of safe work (including work at heights and work with suspended loads) and
use appropriate work and safety equipment.
●Lifting and binding equipment should only be operated by trained personnel.
5.2 Hygienic instructions for the appliance as per VDI 6022
If installation is interrupted or heavy dusting occurs, cover all openings of the appliance in such a way so as to ensure that
surfaces in contact with outside elements remain protected against the weather and stay clean and dry.
Do not unpack and install air filters until immediately before putting the appliance into operation. This prevents their
contamination.
An HVAC duct including other accessories with its own independent operation controls must be connected to the fresh-air
suction side of the appliance in front of the inlet to the appliance to ensure compliance with the VDI 6022 standard and the
appropriate treatment of extract air to eliminate the dampening of the air filter. If the air duct is not fitted or does not contain such
accessories, the appliance must be put out of operation in periods when the dampening of the air filter might occur (thick fog,
flying snow etc.).
5.3 Identification of ports, connecting the HVAC duct
●The versatile design of DUPLEXVENT FLEXI DV1600 and DV2600 allows adjusting the direction of air flow through the
appliance. Identify and label individual ports using the pictures below (labels are included). Begin by identifying port e1 (ODA –
outdoor air inlet) continue towards the fan on the same (shorter) side of the unit with port i2 (exhaust air outlet – EHA). Next is
port e2 (SUP – supply air outlet) with the fan on the opposite side of the unit. The last remaining port is port i1 (inlet extract air –
ETA). Note: Depending on the specific location of the unit proceed clockwise or anticlockwise.
●Connect the HVAC duct following the design documentation.
●To prevent injuries caused by the fan impeller, an HVAC duct at least 2 metres long must always be connected to the unit. The
duct must be fastened in such a way that it cannot be removed without tools.
ATTENTION: For the unit to reach performance levels stated by the manufacturer a straight duct at least 1 metre long must be
connected to all outlet ports. The duct connected to inlet ports must be arranged in such a way so as to allow a uniform flow rate
across the entire section of inlet ports.

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5.4 Installation steps
●Before installation remove the wooden transport planks.
●The versatile design of DUPLEXVENT FLEXI DV1600 and DV2600 allows mounting the unit under the window or in the ceiling.
Window position:
- The appliance is placed on height-adjustable feet (Hmin = 147 mm) included in delivery.
- Due to the condensate drain the appliance must be tilted towards section i2 (EHA).
Ceiling position:
- The appliance is suspended from anchors of sufficient load bearing capacity (provided by the building contractor) using four
suspension eyes (included in delivery) with Ø11 mm holes.
- Due to the condensate drain the appliance must be tilted towards section i2 (EHA), see the picture.
5.5 Adjusting the unit - turning ports e2 (SUP) / i2 (EHA)
●Only units up to DV1600 can be adjusted in this way.
●When making the adjustment, follow the diagram below and the visual instructions in the appendix.
5.6 Connecting the condensate drain pipe
●The unit is versatile and has 4 condensate outlets in total for two directions of air flow and two installation positions. A specific
condensate outlet is always used for a specific application.
- For the window position use the condensate outlet in section i1 (ETA)
- For the ceiling position use the condensate outlet in section i2 (EHA)

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●Connect a pipe or hose (not included; a standard washing machine hose is recommended) to the condensate outlet and shape it
into a siphon trap with dimensions as shown in the picture. Fix the siphon trap shape and connect it to the sewer line.
●Check the entire length of the pipe including the parts inside the unit for free flow and the angle for drainage.
●Prime the condensate drain siphon trap.
5.7 Classification of air filters
●If the unit is supplied with filters of various filtration grades (F7 and F5), then the F7 grade filter is an outdoor air filter and the F5
grade filter is an extract air filter.
●The outdoor air filter is installed in chamber e1 (ODA) and the extract air filter in chamber i1 (ETA).
5.8 Installing air filters
●The unit is supplied with separately packaged filter cassettes. Unpack the cassettes and check their condition. Should any
damage or contamination be detected, replace them with new ones. Spare filter cassettes are to be ordered from the
manufacturer. The manufacturer´s address and the spare cassette part number are shown on the identification plate of the unit.
•Insert undamaged clean filters into the guide rails and secure them following the instructions in the pictures below:
●Especially make sure that the arrow showing the direction of air flow through the filter cassette can be seen from the side of the
operator (the arrow is by the unit´s door) and that it is always pointing toward the heat recovery exchanger!
●The unit is supplied with filter cassette labels. Attach the relevant identification labels near both filters.
ATTENTION:
Record the date of installing filters appropriately in e.g. the operational logbook.
Use original filter cassettes only! If different cassettes are used, the manufacturer cannot guarantee their proper
function!

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5.9 Installation, connecting and filling of liquid manometers (optional accessory)
●Liquid manometers (supplied separately) are used for measuring the pressure loss of air filters. During installation follow the
visual instructions supplied. After installation level the manometers horizontally.
●Connect the manometers to collection points on the unit´s surface using tubes. Connect the tube to the top of the manometer
and run it to the plastic bushing on the unit´s surface. The tube must always connect two matching connection points identified
by symbols “+” / “F+” and “-“ / “F-“ (cannot be combined). Make sure that tubes from just one filter are connected to the
manometer.
●Attach the relevant label near each manometer. Fill out the boxes with the filter grade and record the flow rates and pressure
losses of the clean filter (initial pressure loss) and when clogged (final pressure loss) using data from the table below. The values
must be adjusted on the basis of actual air flow rates through the unit. The label without information completed is included.
DUPLEXVENT FLEXI DV1600
Filter type Flow rate (m3/h) 400 800 1200 1500 1600
F7
Initial pressure
loss (Pa) 16 43 84 126 142
Final pressure loss
(Pa) 200 200 200 200 200
F5
Initial pressure
loss (Pa) 6 14 25 38 43
Final pressure loss
(Pa) 200 200 200 200 200
DUPLEXVENT FLEXI DV2600
Filter type Flow rate (m3/h) 500 1000 1500 2000 2500 2600
F7
Initial pressure
loss (Pa) 10 34 60 91 125 133
Final pressure loss
(Pa) 200 200 200 200 200 200
F5
Initial pressure
loss (Pa) 1 8 17 29 44 47
Final pressure loss
(Pa) 200 200 200 200 200 200
Note: Values in the tables apply to external static pressure 200 Pa. Different pressure requirements may result in a different
situation. If needed, the detailed initial and final pressure loss data of the filters are available on request from the supplier of the
unit.
●Make sure that the position of the labels makes it possible to regularly inspect the recorded values.
●Unscrew the rotating knob as much as possible to zero on the scale (the bottom knob identified by - +), then screw it back by
approximately two full turns ensuring leeway to make settings in both directions.
●Unscrew the FILL plug (the top knob) and keep filling the machine with measuring liquid (included in delivery) until the liquid is
visible near the zero mark on the scale. Use the bottom knob to set the value on the scale to precisely zero. Screw the top filling
plug in.
●
ATTENTION: After installing the manometers do not tilt the machine or the door (if they are installed on the door).
Measurement liquid may leak out.
5.10 Installation and connecting of the hot water air heater (optional accessory)
●During the mechanical installation of the hot water air heater follow the manual supplied with this optional accessory.
The following rules must be adhered to during the installation of the heater:
●The maximum permitted temperature of heating medium is 110 °C and operational positive pressure up to 1.0 MPa.
●For the proper operation of the control set of the hot water heater, the heating system must be fitted with a circulation pump of
suitable power that will fully cover its pressure losses. The pump, which is supplied with the control set, is solely designed to
cover the pressure losses of the water heater!
●If the unit is not equipped with a shut-off damper on the outdoor air inlet e1, a tight shut-off damper must be installed in the
upstream duct of the unit (a type with a servo drive and emergency stop, i.e. which automatically shuts off in the event of a
power cut).
●The inlet of the heating system into the unit must be equipped with a sludge filter.
5.11 Installation and connecting of the control set of the hot water air heater (optional
accessory)
●During the mechanical installation and connection of the control set of the hot water air heater follow the manual supplied.
5.12 Installation and connecting of shut-off dampers e1, i1 (optional accessory)
●During the mechanical installation and connection of the servo drive of shut-off dampers follow the manual supplied.

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5.13 Installation of flexible flanges (optional accessory)
●During the mechanical installation of flexible flanges follow the manual supplied.
5.14 Installation and connecting of the water chiller to the cool source (optional accessory)
●During the mechanical installation of the water chiller follow the manual supplied.
The following rules should be adhered to during the installation of the water chiller:
●The water chiller in all versions must be filled with an antifreeze solution with sufficient thermal resistance, or it must be drained
for the period during which outdoor temperature may fall below 0°C.
●Maximum permitted operating pressure is 1.0 MPa!
●The inlet of the chilled water system into the unit must be equipped with a sludge filter.
5.15 Installation and connecting of the direct chiller (optional accessory)
●During the mechanical installation of the water chiller follow the manual supplied.
●During the connection of the direct chiller follow the instructions of the supplier of condensation units and connecting pipes.
5.16 Installation and connecting of the electric heater / pre-heater EPO-V (optional
accessory)
●During mechanical installation and electrical connection follow the manual supplied.
●Electrical connections may only be carried out by a qualified electrician authorized to service power supply networks.
●Attention - extra care should be taken regarding the installation conditions of the EOP-V heater as they cannot be installed in
randomly selected locations! For specific conditions see the manual included.
5.17 Installation and connecting of manostats to control constant flow rates and pressure
(optional accessory)
●During mechanical installation and electrical connection follow the manual supplied.
6. Electrical connection, commissioning, description of
controls
●The electrical equipment of the unit is designed following standards in effect for electrical connections to power supply networks
TN-C, TN-S and TN-C,S. The appliance may only be connected by a qualified electrician. The appliance is provided with
external connections for equipotential bonding.
●The wiring diagram of the equipment is shown in the appendix that forms an integral part of this set of documentation.
Instructions for and the diagrams of electrical connections of optional accessories are included in the documentation sets of
these accessories.
●The power supply line to the equipment must be fitted with a disconnecting device - a service switch for disconnecting from the
power supply - whose opening contacts are at least 3 mm apart at all poles. This disconnecting device must be installed within
an appropriate distance from the appliance. The protection device included as standard with this unit may act as such a
disconnecting device provided that the switchboard is located within reach of the appliance.
●Commissioning may vary depending on the type of control system. Commissioning is carried out by a trained technician
following the separate documentation set included.
●The controls are described in a separate document entitled “Operating the control system”.
7. Hygienic instructions for the appliance as per VDI 6022
7.1 General instructions
The appliance has been manufactured in a hygienic design that complies with all requirements of the VDI 6022 standard for the
hygiene of HVAC devices. In order to meet those requirements during operation it is essential to ensure for the appliance to be
operated, maintained, inspected and cleaned by sufficiently qualified personnel in accordance with instructions contained in the
operation and maintenance manual. It is also essential to ensure for the remaining components of the HVAC system (HVAC
distribution systems, distribution elements, ancillary devices, noise silencers etc.) to meet all hygienic requirements of the VDI
6022 standard and be operated in compliance with those requirements.
An HVAC duct including other accessories with its own independent operation controls must be connected to the fresh-air
suction side of the appliance in front of the inlet to the appliance to ensure in compliance with the VDI 6022 standard the
appropriate treatment of suction air to eliminate the dampening of the air filter. If no air duct is fitted or does not contain such
accessories, the appliance should be put out of operation in periods when the dampening of the air filter may occur (thick fog,
flying snow etc.)!
Operators should be familiar with the tasks and functions as well as the individual components of the appliance.
The appliance must be regularly inspected, cleaned and maintained by sufficiently qualified personnel (see the following
chapter).
Regardless of their qualifications, personnel must undergo hygiene training (see the following chapter).

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The user must be able at any given time provide evidence as to the qualifications of their operators. If sufficient numbers of
qualified operational and service staff are not available, those activities should be commissioned by a specialist company
that will be responsible for the proper operation of the appliance.
The user has an obligation to carry out regular hygiene inspections of the appliance every 3 years (see following chapters).
The appliance may not be operated without air filters. The filter grade of supply fresh air must be at least F7. The filter grade
of exhaust air must be at least G4.
If the appliance has been out of operation for a prolonged period of time, it should be cleaned thoroughly before
recommissioning; if stricter hygienic requirements apply, disinfecting should be carried out.
After disinfecting, make sure that no toxicologically suspicious or odour-active substances enter the air supply!
The user has an obligation to appropriately record the appliance's operation (e.g. in the operational logbook).
7.2 Required qualifications of personnel as per the type of activity
Activities Operators Inspection Maintenance Repairs
Required personnel
qualifications
No special
professional
qualification
s
Professional engineering
qualifications in building
maintenance, familiarity with
measurement procedures for
the hygiene inspections of
HVAC devices
Professional qualifications in electrical or metal
engineering with relevant experience in the field of
HVAC (familiarity with equipment design,
measurement technologies, equipment control and
function)**
Required hygiene
training of personnel Category B Category A Category B
Simple inspection and maintenance of equipment (e.g. replacing filter fabric, regular cleaning of equipment etc.)
may be
carried out by personnel without professional qualifications who have received category B hygiene training
a) Category B hygiene training of personnel
Personnel should demonstrate familiarity with the following areas:
(1) Need for and the importance of hygiene during the operation of HVAC equipment
(2) Hygiene issues of individual aggregates carrying air through HVAC equipment
(3) Maintenance of HVAC equipment, the effects of its size on determining maintenance intervals
(4) Simple measurement methods for checking HVAC equipment
(5) Actions to be taken in the case of occurrence of substances harmful to the environment and their removal
(6) Personal protective measures in the area of hygiene during operation and service activities
(7) Key regulations (in particular regulations on accident control) and technical standards
(8) Handling chemical cleaning and disinfecting agents
a) Category A hygiene training of personnel
Personnel should demonstrate familiarity with the areas of category B training specifications in addition to the following:
(1) Hygiene basics
(2) Significance of the various hygienic methods of air treatment
(3) Physical and chemical measurement methods, hygiene and microbiological inspection methods
(4) SBS (Sick-Building-Syndrome) issues, symptoms of problems and possible causes
(5) Technical development and its practical applications
(6) Hygiene regulations and technical rules for the operation of HVAC equipment
8. Inspecting the appliance
8.1 Overview of inspections and measures to ensure compliance with hygiene
requirements
The appliance must be regularly inspected for the following areas from the list below
Required interval in calendar months
Activity Measures to be taken 1. 3. 6. 12. 24. Hyg.
inspection
2
Unit´s cabinet
2.
1 Check for impurities on air side, damage and corrosion Clean and repair x
2.
2 Check water production Clean, determine causes and
repair x
3
Air filters
If these instructions are not adhered to, the manufacturer cannot guarantee the permanent
maintenance of the unit´s hygiene requirements.

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Required interval in calendar months
Activity Measures to be taken 1. 3. 6. 12. 24. Hyg.
inspection
3.1 Check for unacceptable impurities
and damage (leaks)
Replace affected air filters if no
replacement has taken place
within the previous 6 months,
otherwise replace the entire
filter stage
x
3.2 Check differential pressure Replace filter stage x
3.3 Replace filters that cannot be
regenerated later, clean thoroughly x
3.4 Check hygienic conditions x
4 Drop eliminator
4.1 Check for impurities, damage and
corrosion Cleaning and functional maintenance x
4.2 Check drop eliminator for deposits Cleaning and functional maintenance in case of visible
deposits x
4.3 Check hygienic conditions x
5 Heat exchangers
5.1 Check for impurities, damage and
corrosion Cleaning and repair x
5.2
Check for impurities and corrosion,
check water chiller, condensate
tray and drop eliminator for
functionality
Repair
x
5.3 Check for impurities and
functionality of siphon trap Cleaning and repair x
5.4 Cleaning water chiller, drop
eliminator and condensate tray x
5.5 Check hygienic conditions x
6 Fans
6.1 Check for impurities, damage and
corrosion Cleaning and repair x
6.2 Cleaning functional maintenance of air-carrying fan parts and water
discharge x
7
Heat recovery exchanger
7.1 Check for impurities, damage and
corrosion Cleaning and repair x
7.2 Check tightness between exhaust
and outdoor air Repair x
7.3 Check condensate tray for impurities, corrosion and
functionality Cleaning and repair x
7.4 Check for impurities and
functionality of siphon trap
Cleaning and repair x
7.6 Check hygienic conditions x
8 Air duct and noise silencers
8.1 Check accessible sections of air
duct for damage Repair x
8.2 Check internal air duct surfaces at
two or three sample points for
impurities and corrosion
Determine cause, clean
relevant air duct sections x
8.3 Check noise silencer for impurities,
damage and corrosion Repair x
8.4 Check hygienic conditions of air
duct at sample point Determine cause, clean relevant air duct sections x
9 Air vents
9.1 Check mounted perforated metal
sheet, wire mesh or screens
(random checks) Clean or replace x

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9.3 Check around air vents with room air induction and extraction air
outlets for solid deposits Clean
If
nece
ssar
y
9.4 Clean structural parts of secondary
air flow x
While checking air filters make sure the following is documented (e.g. in the operational logbook):
−Pressure difference
−Time of operation
−Appearance (check for cracks in filter material and leaks between the frame and mounting wall)
If significant contamination or cracks are present the air filter should be replaced!
Hygiene inspections should be carried out regularly every 3 years. As per the requirements of the VDI 6022 standard the
inspection must include the following steps:
−Inspecting the application and rooms it supplies with the company´s doctor and HR representative in attendance, with
attention paid to apparent deficiencies
−Measurement of physical climatic parameters (temperature, humidity, air flow rate) at sample points in the appliance and in
the rooms
−Inspecting hygienic conditions including specific tapping on filters and heat exchangers
−Checking the total content of Legionella germs (must be carried out by the hygiene authority)
−A written report on the inspection results to the user with recommendations and required corrective measures during a
business meeting
The total number of Legionella germs should not exceed 1 KBE/ml.
All inspections should be documented
9. Cleaning and maintenance
9.1 General
●During the maintenance of the appliance follow instructions from the previous chapters, observe the basic rules of safety at work
and proceed in compliance with the working regulations and use suitable means of access to the HVAC equipment (ladders,
mobile stepladders, platforms etc.).
●Maintenance consists particularly in the visual inspection of the appliance, a regular replacement of air filters and cleaning the
heat recovery exchanger.
●Observe personal hygiene during the maintenance of the appliance. We recommend using personal protective equipment (face
masks, rubber gloves etc.).
●We recommend commissioning the maintenance and cleaning of the appliance to a specialist service company.
9.2 Cleaning the cabinet
●After opening the door of the unit vacuum clean all impurities. Possibly wipe clean and disinfect.
●Check the condition of the door seal.
●Check the condensate drain for cleanliness and flooding.Ablocked drain might cause serious problems.
9.3 Air filters, replacing filter cassettes
●As standard, the appliance contains outdoor (e1/ODA) and extraction air filters (i1/ETA), which should be regularly replaced.
●The filters are designed to capture dust particles and thus protect your health as well as the other parts of the appliance from
contamination; therefore make sure they are replaced regularly!
●Only carry out filter replacement operations if you do not suffer from allergies to dust particles. Avoid replacing filters when
persons with such allergies are present.
●Replacement is carried out depending on the dust load of the external and internal environment and the subsequent
contamination of filters and an increase in air resistance indicated by the differential manostats every 500 to 2000 running hours.
The filter cassettes are replaced when the final permitted difference between filter pressures or the time interval for replacement
have been reached, or if the filters show technical or hygienic functional defects. Earlier replacement or shorter replacement
intervals are desirable if the results of a hygiene inspection show it appropriate.
When replacing the filter cassettes, avoid the contamination of the surroundings, other air-handling parts of the appliance as well
as the rooms being ventilated. In particular make sure that the newly installed filters have not been contaminated by dust from
the old ones!
●Spare filter cassettes are to be ordered from the manufacturer. Please include in your order the order code of the cassette (the
code is shown on the identification plate of the appliance).
●After opening the unit door, slide out the contaminated cassettes from the guide rails and insert new ones.
●During insertion make sure that the identification plate of each filter cassette faces your direction (i.e. the appliance door) and
that the arrow showing the direction of air flow always points toward the heat recovery exchanger!
●Make sure that each section (supply, exhaust) has filter cassettes with the correct filter grade as indicated on the identification
plate of the appliance.
●Dispose of the contaminated cassettes with general municipal waste.

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ATTENTION:
Always record the date of replacement of filter cassettes in a suitable way, e.g. in the operational logbook.
Only use original filter cassettes! If different cassettes are used, the manufacturer cannot guarantee their
proper function!
9.4 Cleaning heat exchangers (heater / chiller)
It is necessary to clean the exchanger when it only shows minimum signs of contamination.
●After opening the door vacuum clean all impurities.
●If the vacuum cleaning of impurities while the exchanger remains in its place does not suffice, disconnect it from the heating /
cooling medium, remove it and clean it using a high-pressure cleaner.
●When cleaning the exchanger proceed in such a way so as to prevent impurities or moisture from entering other parts of the
appliance.
9.5 Cleaning the plastic heat recovery exchanger
●The recommended period for cleaning the exchanger is approximately 30 to 50 thousand running hours depending on the nature
of the operating environment.
It is necessary to clean the exchanger when it only shows minimum signs of contamination.
●After opening the door and unlocking the fixing elements, slide individual recovery exchanger blocks out of the guide rails in the
following order: DUPLEXVENT FLEXI DV1600 - 1, 2, 3, DUPLEXVENT FLEXI DV2600 - 2, 1, 3, 4. Rinse the individual blocks
with hot water containing detergent at a maximum temperature of 70°C.
●After letting them dry thoroughly, slide the individual heat recovery exchanger blocks back in in the reverse order and secure
them in place.
●Check for a tight fit of the exchanger in the guide rails.
●Do not expose the exchanger to ultraviolet light; store it in darkness if necessary.
ATTENTION: Never clean the exchanger with agents that might contain organic solvents - there is a risk of irreversible
damage to the exchanger!!
9.6 Draining and inspection of the condensate collection tank (not included in delivery)
●If the condensate is drained into a sufficiently large and accessible tank, make sure it is inspected and drained regularly.
●Make sure the tank is easily accessible; keep it clean!
9.7 Other minor maintenance
●When replacing the air filters also check the following:
- Cleanliness of the condensate drain. Ablocked drain may cause serious problems.
- Condensate drain flooding.
- Door seal condition.
●Regularly check the liquid level in the manometers, if necessary adjust the zero value using the bottom knob (marked with - +).
Before adjusting to zero make sure that no pressure enters the manometer by disconnecting both hoses located on the top of
the appliance.
●Also regularly check the condition of the sludge filter (part of the heating / cooling system) on the inlet of heating / cooling water
into the hot water heater / water chiller.
●Keep the heating/cooling systems including the heater / chiller and the control set bled of air. Check pressure in the heating /
cooling system.
10. Failures and troubleshooting
Failure Symptoms Possible causes Troubleshooting
Appliance will not start
up
- Power supply is not connected
- Connect to power supply (switch on primary
circuit breakers)
- Power supply or interconnecting electric
cables are interrupted
- Disconnect from power supply and contact
a service technician
- Not found - Disconnect from power supply and contact
a service technician
Appliance supplies
insufficient air volume
- The appliance supplies
considerable lower air
volumes
- Clogged air filters
- Switch off the appliance
- Disconnect from power supply
- Replace air filters
- Mechanical obstruction in fresh air
intake or supply air outlets
- Look for mechanical obstructions of fresh air
inlet ports
- Look for mechanical obstructions of supply air
outlets
- Remove obstructions, if any
- Not found
- Disconnect from power supply and contact
a service technician

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Failure Symptoms Possible causes Troubleshooting
Appliance does not
heat at all or heats
insufficiently
- Cool air is supplied
continuously
- Air in hot water heater - Check heating water temperature
- Bleed air
- Heating water temperature in the hot
water heater too low
- Check heating water temperature
- Heating water flow rate too low - Check the condition of the sludge filter on the
heating water inlet; clean the filter
- Maximum heater capacity too low - No failure (incorrect design capacity - too low)
- Not found - Disconnect from power supply and contact
a service technician
Appliance does not
cool at all or cools
insufficiently
- Warm air is supplied
continuously
- Air in water chiller
(only in CHW version) - Air bleed the water chiller
- Cooling water temperature too low (only
in CHW version) - Check cooling water temperature
- Cooling water flow rate too low (only in
CHW version) - Check the condition of the sludge filter on the cooling water inlet; clean the filter
- Condensation unit is not running (only
in CHF version) - Switch on the condensation unit
- Maximum chiller capacity too low - No failure (incorrect design capacity - too low)
- Not found - Disconnect from power supply and contact
a service technician
Water dripping from
appliance
- Drops of water form
between the door and
frame of the appliance
during operation
- Condensate drain siphon trap is
insufficiently filled with water - Disconnect from power supply and fill the condensate drain siphon trap with water
- Condensate drain is blocked
- Disconnect from power supply and clean
the condensate drain including the siphon trap
and pipes
- Damaged door seal
(the symptoms might include a whistling
sound caused by air flowing through the
gap)
- Disconnect from power supply and check
the condition of the door seal
- If serious damage is discovered, contact a
service technician
- Water drops from at the
condensate drain
connection point
- Condensate drain seal or pipes
damaged - Disconnect from power supply and contact a service technician
- Not found - Disconnect from power supply and contact
a service technician
ATTENTION: If the unit is disconnected from the electricity supply, follow the instructions given in chapter 3.2 Operational
safety.
●For further description of possible problems and troubleshooting contact your supplier of the control and measurement system.
11. Repairs, spare parts
All warranty and post-warranty repairs are performed by the manufacturer or an authorized service company. Service technician will
have an updated list of spare parts; you can also contact the manufacturer.

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12. Visual appendix - manuals
12.1 Turning the fan

16
12.2 Connecting the condensate drain outlet

17
12.3 Installing filters

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13. Warranty
The product is covered by warranty according to general delivery terms and conditions and the warranty conditions of the
manufacturer, which are a part of the accompanying documentation.
This product has a warranty period of two years from the date of purchase against faulty material or workmanship.
The warranty covers the product only and not the installation cost.
In case such a fault in the manufacture becomes apparent during the Warranty Period, Airflow may, at its absolute discretion, repair
the product free of charge or refund the cost of the productAS LONGAS AND ONLY IF:
1. The product is returned within the Guarantee Period with evidence of purchase date
2. The product has not been misused or handled carelessly or used on an inappropriate voltage supply
3. Repairs have not been attempted other than byAirflow’s service staff or
4. In Airflow’s sole discretion, the product is found to be faulty. If it were not found to be faulty, the product would be
available for collection from the relevantAirflow premises within one calendar month and if it was not collected, it would
be subsequently delivered byAirflow and a delivery charge will be made.
This warranty does not confer any rights other than those expressly set out above and does not cover any claims for consequential
loss, damage or any costs incurred in the replacement of the faulty product.
Airflow Developments Ltd. is not liable for damage caused by unprofessional installation and operation that is not in compliance with
the operation and maintenance manual and general practices applied during installation and operation of HVAC equipment and
control systems.
This warranty is offered as an extra benefit and does not affect your statutory right as a consumer.
All information believed correct at time of going to press.
All goods are sold according to Airflow Developments Limited’s Standard Condition of Sale which is available on request.
In the interest of continuous development Airflow Developments Limited continuously strive to improve their products and reserve the
right to change specifications and prices without prior notice.
©Copyright 2011. Airflow Developments Ltd
Airflow Developments Limited
Aidelle House, Lancaster Road
Cressex Business Park, High Wycombe,
Buckinghamshire. HP12 3QP. U.K
www.airflow.com
E-mail: [e-mail]
Telephone: [phone]
Facsimile: [phone]