MODEL: BV400 Part No:

MODEL: BV400 Part No: 90000312 Mechanical Ventilation with Heat Recovery Installation and Commissioning Manual PLEASE RETAIN THESE INSTRUCTIONS WITH THE PRODUCT

INDEX 1. Introduction... 3 2. General Instructions... 3 3. Product Description... 5 4. Technical Data... 6 5. Performance Curve... 7 6. Sound Curve... 7 7. Dimensions... 8 8. Installation... 9. Operating Connections... 9 19 10. Maintenance Instructions... 24 11. Accessories... 26 12. Troubleshooting... 27 13. Warranty... 28 Page 2 of 28

1. Introduction Dear Customer, Thank you for choosing a Duplexvent Basic Line ventilation system. Please read and follow the instructions in this manual carefully before you start installing your equipment. In this document you will find instructions for mounting, commissioning and maintenance which are necessary to operate your unit properly and improve the longevity of your ventilation system. This technical guide is intended for professional installers. If you have any further questions, please contact: Airflow Developments Limited Aidelle House, Lancaster Road, Cressex Business Park High Wycombe, Buckinghamshire, HP12 3QP United Kingdom Tel: (Int +44) (UK 0) 1494 560800 Fax: (Int +44) (UK 0) 1494 461073 E-mail: info@airflow.com Visit: www.airflow.com Please keep this manual in a place where it is accessible at all times. In case of loss of this document please refer to the product page on our website. The manufacturer is not liable for damage caused by unprofessional installation and operation that is not in compliance with this manual. Failure to follow these instructions may cause the loss of product warranty. 2. General Instructions To maintain a healthy indoor environment, closely controlled ventilation is essential. There are many pollutants that will affect the indoor air quality: biological, dead skin, perspiration and moisture. Add to this the waste products of cooking (cooking smells), showering (moisture), gases from building materials and the bi products of pets. Without proper ventilation this would be the perfect environment for the growth of mould, subsequent damage to the fabric of a home and to the health of its occupants. This heat recovery unit is fitted with two, low energy EC fans with balanced (100% adjustable) air volume. The system operates on the principle of air exchange complying with the energy utilization regulations according to DIN 1946, which ensures hygienic and sanitary conditions in the house at the nominal fan speed. The filters in the unit ensure that the fresh supply air is clean as it enters the home. Also, the extract air from the property is filtered to protect the heat exchanger from unwanted contamination. These filters should be maintained depending on the level of pollution and replaced after a maximum of two cleaning cycles (6 months). Page 3 of 28

It is important to follow the advice in this manual and correctly maintain the system to ensure a healthy indoor environment. 2.1 Safety Instructions Do not install this product in areas where the following may be present or occur: * Corrosive or flammable gases, liquids, vapours or excessive grease laden atmosphere. * Ambient temperatures higher than 40 C and lower than 5 C. * Possible obstructions that may hinder access to the unit for servicing purposes. All wiring must be in accordance with the current IEEE wiring regulations. Installations should be inspected and tested by a suitably qualified person after completion. All regulations and requirements must be strictly followed to prevent hazards to life and property, both during and after installation. Before opening the door of the unit for cleaning, filter replacement or general maintenance always make sure that the equipment is disconnected from the power supply and prevent its reconnection by another person. This appliance should only be used after the user and maintenance manual has been read. 2.2 Installation Instructions The installer is responsible for the installation and electrical connection of the Duplexvent unit on site. It is the responsibility of the installer to ensure that the equipment is safely and securely installed and left in a mechanically and electrically safe condition. Intended use includes compliance with the user and maintenance instructions provided by Airflow Developments Ltd. Only qualified persons are permitted to carry out the installation and commissioning of the unit. In addition, the end user should be handed a copy of these instructions and shown all the main elements of the complete system on hand over. When installing the unit, please make sure that the mains supply (voltage, frequency and phase) complies with the rating label. This unit must be earthed. This appliance is not suitable for outdoor installation and should not be used for dehumidification purposes. It may only be installed in suitable and temperate indoor conditions. The condensate drain for the unit should be sited in a frost-free area. If this is not possible the drain pipe should be insulated to protect against freezing. If ductwork passes through an unheated area such as loft void or similar location it should be insulated. The supply and exhaust air must only be vented to the exterior of the property. If an extract grille associated with the unit is sited in a room containing a fuel burning appliance, the installer must ensure that air replacement is adequate for both appliances. If there is any doubt the manufacturer of the fuel burning appliance should be consulted. Page 4 of 28

2.3 Commissioning and Operating Instructions This equipment may only be put into operation after the control switch has been properly installed and connected to the unit. The supply and exhaust valves must be fully opened prior to commissioning. They should be positioned a minimum of 300mm from obstacles to enable air flow measuring equipment to fit correctly over the valve. The condensate drain and associated pipe work must be clear of any debris prior to commissioning. It is recommended that open ended ducts are sealed off and air valves are closed until any building work is completed in order to stop any ingress of contaminants. When fitted to a new build property or one that has had recent building work of any kind, the supply and exhaust filters should be checked at one month intervals for the first six months for excessive dust build-up. Certain applications may require the installation of sound attenuation devices to achieve the sound levels required. DO NOT switch off the unit it is designed to run continuously. If the unit is switched off, indoor pollutants and moisture levels may increase which could endanger your health or damage your home. 3. Product Description Duplexvent BV400 Duplexvent BV400 is a ventilation unit with state-of-the-art technology suitable for medium and large size houses. The unit is designed for continuous 24 hours exhaust ventilation of stale moist air from bathrooms, toilets and kitchens. As the stale air is extracted, a heat exchanger within the unit transfers more than 90% of the heat into the supply air entering the bedrooms and lounge etc. 5 6 1 2 3 1 2 3 Control Box Extract & Supply Air Filters By-pass Module 4 4 Heat Exchanger 6 5 6 Metal Casing Extract & Supply Air Fans Page 5 of 28

5. Technical Data Performance EC Fan Speed settings selected on installation (Low & High speed levels are 100% adjustable) Low Middle High Boost Typical Ventilation Settings at 100 Pa 75 m³/hr 200 m³/hr 350 m³/hr 425 m³/hr Rated Voltage 3.0 V 5.5 V 8.0 V 10.0 V Maximum Air Volume (at 0 Pa) Air Volume (at 100 Pa) 475 m ³ /hr (132 l/s) 425 m ³ /hr (118 l/s) Thermal Efficiency (ref. SAP Appendix Q) 93% Specific Fan Power (ref. SAP Appendix Q) 0.45 W/l/s Power Power Supply Maximum Power Input Maximum Current Supply Fuse 230V / 1PH / 50Hz 180 W 1.54 Amp 3 Amp (for standard unit) 13 Amp (for additional accessories such as heaters) Physical Dimensions (W x H x D) Weight Filter Class (conforming to EN779) Duct Connection Ø Condensate Discharge Ø Protection Class 710 x 725 x 630 mm 41 kg G4 (F7 optional) 160 mm 22 mm IP44 Operation Operating Temperature Operating Humidity -10 C to +40 C 0% to 80% rh Page 6 of 28

6. Performance Curve 500 450 External Pressure (Pa) 400 350 300 250 200 150 Low Speed Medium Speed High Speed Boost 100 50 0 0 50 7. Sound Curve Octave Sound Pressure Level (db: Overall A Scale ) db(a) 60 50 40 30 20 100 150 200 250 300 350 400 450 500 550 Air Volume (m³/h) NR20 NR30 NR10 NR0 10 63 125 250 500 1000 2000 4000 8000 Hz Central Frequency (Cycle per Second) Page 7 of 28 NR50 NR40 Low Speed Medium Speed High Speed Boost

7. Dimensions Front View Top View 160 Rear 130 475 103 10 733 731 725 630 610 287 116 23 710 Front Service Space Front View Top View Rear min. 110 mm. Clearance for condensate drain Front A clear space of 600mm should be provided in front of the unit to allow for servicing. *All dimensions are in mm. Page 8 of 28

8. Installation The Duplexvent BV400 is suitable for floor or wall mounting. Units are typically installed in utility rooms, storage cupboards or similar areas. When wall mounting, consideration should be made regarding the wall's strength and its suitability. When floor mounting, please ensure that there is enough space below the unit to accommodate the condensate drain. Take into consideration the position of the electrical equipment and ensure there is adequate access for installation, operation and maintenance. The unit should always be mounted vertically with ducting exiting the unit vertically. Care should be taken when choosing the location of the unit. Although care has been taken in the design of the unit, some mechanical noise may be transmitted through the unit. 8.1 Selecting The Unit Configuration The unit is supplied from the factory as a right handed version (see Figure 1). If needed, the unit can be changed to the left handed version in which the outdoor air enters the unit from the left hand side when viewed from the front of the unit (see Figure 3). Installing the unit in the opposite handing involves removing the front door cover and rear cover, rotating them 180 degrees, and re-attaching them on the opposite sides of the unit ie: The front cover to the back and the back cover to the front. Remove the front cover (4 screws) and rear (6 screws) cover by unscrewing the fixing screws. EA SA OA RA Fig. 1 Duplexvent BV400 (right handed standard delivery) EA SA OA RA Exhaust air to atmosphere Supply air to dwelling Outdoor air from atmosphere Return air from dwelling Page 9 of 28 Fig. 2 Removing the front and rear covers

RA OA SA EA EA SA OA RA Exhaust air to atmosphere Supply air to dwelling Outdoor air from atmosphere Return air from dwelling Fig. 3 Duplexvent BV400 (left handed) 8.2 Optional Spigot Installation The Duplexvent BV400 has a number of options regards positioning of the four entry/exit spigots. This enables more flexibility when positioning the heat recovery unit and system ducting. For example connection to the unit from the bottom. The standard unit supplied is configured for top entry connection. It is possible to configure the unit for bottom entry connection should space consideration for connecting duct runs necessitate it. Spigots OA and RA may be separately (ie: one or both of them) re-located to the bottom of the unit if required. However, if spigots SA and EA are needed to be moved they must be BOTH moved and relocated together. If the unit has been modified into a left hand unit (as section 8.1) then the opposite procedure to the above is necessary. Relocating spigots RA and OA (if required) Remove the relevant spigot/s by unscrewing the 4 screws on the top of the unit. Remove the corresponding blanking cap at the bottom of the unit by unscrewing the 4 screws. After removing this blanking cap also remove the sealing cap. Spigot Sealing Cap Blanking Cap Fig. 4 Duplexvent BV400 spigot relocation Page 10 of 28

Swap the spigot with the relevant removed blanking and sealing caps. Insert the spigot into the entry/exit hole and secure with the retaining screws. Insert the blanking and sealing cap into the entry/exit hole and secure with the retaining screws. EA SA EA SA OA EA SA RA EA SA OA RA Exhaust air to atmosphere Supply air to dwelling Outdoor air from atmosphere Return air from dwelling OA RA RA OA Fig. 5 Optional OA and RA spigot variations Note: Always fit the sealing and blanking caps to the entry or exit hole not in use to ensure the correct air flow into and out of the unit. Relocating spigots SA and EA (if required) Remove the relevant spigot/s by unscrewing the 4 screws on the top of the unit. Remove the corresponding blanking cap at the bottom of the unit by unscrewing the 4 screws. After removing this blanking cap also remove the sealing cap. Remove the front cover, bypass module and heat exchanger respectively. Fig. 6 Remove the front cover, bypass module and heat exchanger Page 11 of 28

Remove the fan module, rotate it 180 vertically. Re-install the fan module, heat exchanger, bypass module and front cover respectively. Control Box Fan Module Bypass Module Heat Exchanger SA EA Front Cover Fig. 7 Rotate the fan module and re-install it matching air paths EA-SA as shown Fan Module Note: Remove the electrical connections of the fans from the back of fan module (see figure 8). Re-connect the electrical connections of the fans in the opposite direction (EA as SA, SA as EA). Fig. 8 Changing the fan connections Page 12 of 28

Swap the spigots with the relevant removed blanking and sealing caps. Insert the spigots into the entry/exit holes and secure with the retaining screws. Insert the blanking and sealing caps into the entry/exit holes and secure with the retaining screws. OA RA EA SA OA RA Exhaust air to atmosphere Supply air to dwelling Outdoor air from atmosphere Return air from dwelling EA SA OA EA SA OA RA RA Important Note: You cannot change the SA and EA spigots separately. Both spigots must be installed next to each other, either on the top or at the bottom of the unit (see Figure 9). EA SA RA Note: Duplexvent BV400 units have spigots suitable for 160mm ducting and have a rubber seal incorporated to enable leakage-free connection. For the best performance we recommend our Airflex ISO insulated rigid ducting be used in conjunction with the Airflex PRO semi-rigid ducting system (details can be found on www.airflow.com). 8.3 Installation The Duplexvent BV400 should be installed vertically. The unit is suitable for wall or floor mounting in a position where the temperature does not fall below 5 C. Please check that the unit is configured correctly and ensure that there is enough space for the condensation fitting, duct connections and future servicing. The contents include: 1 x BV400 Ventilation Unit 1 x BV400 Control Switch 1 x User and Maintenance Manual 1 x Installation and Commissioning Manual 2 x Mounting Brackets (for wall or floor installation) 4 x Wall Screws (Ø5 x 40) and 4 x Plugs (Ø7) 8 x Small Screws (M5 x 10-8,8) (for wall installation) 4 x Small Screws (4.8 x 15-8,8) (for floor installation) 2 x Screws (Ø4 x 30) and 2 x Plugs (Ø6) (for control panel) Page 13 of 28 EA SA OA Fig. 9 Optional EA and SA spigot variations

8.3.1 Wall Mounting Important Note: Before starting the installation, please ensure that the wall selected is suitable to withstand the weight of the unit (41 kg). Note: Incorrect installation may cause excessive noise levels. The unit should ideally be installed onto a medium density block wall. If the unit is to be mounted onto a stud wall, then it should be screwed directly onto the studs, using the mounting brackets provided. If space is limited and it is not possible to screw directly onto the studs, then additional battens should be fitted to the studs and the unit secured to these battens. Unit Installation: Screw the two mounting brackets (supplied) to the rear cover, using the eight small screws provided (4 along the top bracket and 4 along the bottom bracket) (see Figure 10). Position the four screws and wall plugs (2 x top, 2 x bottom) in the wall based on the distance between the holes on the mounting brackets (see Figure 11). If the four screws and wall plugs supplied do not suit the fabric of the wall, suitable fixings should be provided by the installer. Fig. 10 Installing mounting brackets Mount the unit on the wall by attaching the unit complete with brackets to the screws on the wall. Brackets should fit over the screws giving a secure fit between the screw head and the wall. 600 Fig. 11 Wall Installation Page 14 of 28 500

8.3.2 Floor Mounting Note: Before installation please ensure that there is enough space under the unit for the condensate drain. Unit Installation: Remove the base feet (four pieces) from the bottom of the unit. Install both mounting brackets to the bottom of the unit, using the four small screws (2 along the right bracket and 2 along the left bracket) before attaching the base feet to the brackets. The same mounting brackets are used for installation on the wall or on the floor 23.08 Fig. 12 Installing mounting brackets 8.4 Condensate Discharge During the heating season, humidity from extract air condenses in the unit. This should be drained out of the unit in order to prevent damage to the unit and duct system. The unit comes complete with a condensate drain fitting on the under side. min. 110 mm. Fig. 13 Condensate discharge for wall and floor mounting Clearance for condensate drain Page 15 of 28

A standard 22 mm condensate pipe is suitable for connection to an appropriate drain location. Please ensure that the drain incorporates a U-bend to prevent air penetration back to the unit. Care should be taken to ensure that there is enough space to clean the condensate U-bend at a later date. The condensate pipe should be installed to have a minimum of 5 fall from the unit. Fig. 14 Condensate pipe connection Note: The condensate U-bend should be checked at regular intervals for any blockages and that there is sufficient water in it. Any condensate pipe installed outside the insulated envelope of the building should be insulated to protect against freezing. 8.5 Electrical Connections WARNINGS Mains supply voltages (230V AC) are present in this equipment which may cause death or serious injury by electric shock. Only a qualified electrician or installer should connect the power supply to this unit. This unit must be correctly earthed. Danger Electric Shock risk To connect the power supply: Ensure the electric circuit allocated to the unit is securely isolated. The unit is supplied with a 3 metre long fly lead (3-core x 1.5 mm²) for connection to the power supply. A switched fused spur should be provided for electrical connection (Fuse Rating: 3 Amp for standard unit, 13 Amp for unit with heater). This enables the unit to be isolated for service and maintenance purposes. Page 16 of 28

ON CEY 1 2 3 4 8.5.1 Control Switch Mounting The unit is supplied with a three speed control switch as standard. The control switch is suitable for surface mounting with the connecting low voltage cable recessed into the wall (recommended). * Channel out the wall to run the cable to the required location (see Figure 15) * Drill a hole (15mm diameter x 15mm deep) to recess the connecting plug in the surface. * Alternatively, if surface mounting of the connecting cable (within conduit) is required, there is an optional cut-out in the top of the controller which allows surface cable entry. Cable connected to the MVHR unit Control Switch * Remove the metal plate from the switch and mount it on the wall using two screws (supplied). * Connect the cable to the control panel. * Fix the control panel to the metal plate using the screw at the bottom of the switch. * The unit is supplied with a 5 metre long cable with plugs to connect the control switch to unit. (see wiring diagram). 8.6 Fan Speed Adjustment Wall Fig. 15 Control switch mounting Persons commissioning the finished ventilation system are responsible for setting the required air volume rates which should be set according to the relevant guidelines and approved documentation by a competent person. This is to ensure correct ventilation rates at the most economic unit settings. The low and high speed levels can be adjusted using two potentiometers found on the PCB in the control box. To increase fan speed turn the potentiometers clockwise. PCB Diagram Connection Socket for Control Switch Cable Fan speed potentiometers Page 17 of 28 Potentiometer for Low Speed Potentiometer for High Speed Medium speed will be set automatically by the controller's software taking the mid-point of the High and Low fan speed settings.

8.7 Wiring Diagram 400V 3 PHASE 400V 3 PHASE 230V 1 PHASE 230V 1 PHASE Page 18 of 28

9. Operating Instructions Continuous ventilation is necessary to ensure a healthy indoor air quality and to maintain the building fabric in good condition at all times. Even with prolonged absence of residents (ie. holiday) it is not recommended to switch off the ventilation unit since indoor contaminants are still being produced and entering the air, causing the air to get stuffy and a high possibility of moisture damage due to excess humidity during the heating season. Do not turn off the device! This is required for protection against moisture in accordance with DIN 1946 Part 6 and Building Regulations 2010 Approved Document Part F. The ventilation unit works properly when the flow rates are adjusted in accordance with the above regulations to ensure optimum ventilation of the house. Default Factory Settings Parameters Low Speed Supply/Extract Medium Speed Supply/Extract High Speed Supply/Extract Boost Speed Supply/Extract* Manual Boost Overrun* On-demand Boost Delay* Filter Timer* Requested Indoor Temperature* Indoor Temperature Selection* Defrost Temperature* Defrost Cycle* Pre-heater Temperature* Settings 30% (3V) 55% (5.5V) 80% (8V) 100% (10V) 15 min 1 min 3000 hours 22 C Extract Air Temperature -3 C 15 min 0 C Note: The low and high speed levels can be adjusted by manual potentiometers. The medium speed has been set in the controller's software by the manufacturer and is set as the average value of the manually adjusted low and high speed levels. * These values are factory set and can only be adjusted via the digital controller (BV400 SE). Page 19 of 28

9.1 Basic Control Settings ON/OFF: Press for 3 seconds. Press to increase fan speed. Press to decrease fan speed. Press to activate the manual boost function. Child Proof Protection: To activate this function, press and simultaneously for 3 seconds. When child proof protection is active, keypad is locked and buttons do not work. To deactivate this function press and for 3 seconds. 9.2 Fan Speed Adjustment The installer is responsible for setting the required air volume rates for every room in compliance with the Domestic Ventilation Compliance Guide 2010. The Duplexvent BV400 unit has a 3-speed control switch which is supplied as standard. The low and high speed levels can be adjusted by manual potentiometers for commissioning purposes. This can be done through the control box which is located on top of the unit. The medium speed has been set in the controller's software by the manufacturer and is set as the average value of the manually adjusted low and high speed levels. Page 20 of 28

9.3 Other Control Functions Boost Function This function is used when large amounts of exhaust and fresh air are required. There are 2 different boost functions (Manual and On-demand): a) The Manual Boost function is activated after pressing the Boost button on the control panel Once activated, the unit runs at the boost speed for 15 minutes. Note: During the manual boost operation the Low, Medium and High speed LED lights flash at the same time. b)the On-demand Boost function is activated via volt-free or switched live contact (see section 11) on the control board. When activated, the unit starts running at the High speed until it is deactivated and goes back to the speed level that was set before the boost operation. Summer Bypass Volt-free connection for boost Switched live connection for boost Requires both a switched live and neutral The Duplexvent BV400 unit is fitted with a bypass facility as standard. This can be used for keeping indoor air temperature at a comfortable level. If the house indoor air temperature is hotter than the unit temperature sensor setting (factory set at 22 C), with the incoming air temperature lower than the indoor air temperature, the bypass damper will open. This will tend to lower the indoor air temperature until it reaches the set temperature level (22 C). Page 21 of 28

At other times the unit will recover heat as long as the related dip switch in the control box is activated. The bypass function is activated from dip switch 1 in the control box on top of the unit. ON CEY 1 2 3 4 This can be switched off in the heating season to have heat recovery at all times. Frost Protection In case of very low outside temperatures, the supply fan will reduce its speed automatically for a short period to protect the heat exchanger from freezing. This function is active when the outdoor air temperature falls below -3 C. For uninterrupted air supply and extract volumes in regions with low outside temperatures (< -5 C for more than 24 hours), an in-line electric pre-heater (see section 11) can be used in the supply air stream from the outside to the dwelling to avoid the heat exchanger freezing. The heater automatically switches on when the outdoor air temperature falls below 0 C. Once installed, the pre-heater control must be activated from dip switch 2 in the control box on top of the unit. Filter Maintenance Indicator The unit is fitted with a maintenance reminder facility which has been pre-set to 4 months. When this time interval is reached the red warning light on the control panel flashes for filter maintenance indication. After cleaning/replacing the filters press the and buttons simultaneously for 3 seconds to reset the timer. Alternatively, optional pressure sensors (see section 11) can be used to measure the actual pressure difference between supply and exhaust air hence monitor the filter status. The red warning light on the control panel flashes as soon as the filters need to be maintained. After cleaning/replacing the filters, the red warning light goes off automatically. Page 22 of 28

Electric Post-heater For most of the year, heat recovered from the extracted air is sufficient to warm the fresh incoming air to the required temperature. If the heat gain from the extract air is not sufficient an optional post-heater (see section 11) can be used to increase the indoor air temperature. The heater is switched on/off automatically based on the extract air temperature in order to maintain the requested indoor air temperature (factory set at 22 C). Once installed, the post-heater control must be activated from the dip switch 3 in the control box on top of the unit. Fire Switch This volt-free contact can be used to shut down the unit in case of a fire or any other emergency. A volt-free switch should be connected to the corresponding socket to activate this function. MODBUS Control / MODBUS Monitor The MODBUS (via RS485) BMS control function helps to control the functions from a central automation system. For more information, please contact our technical support team. The MODBUS BMS monitoring enables the user to display the operating status of the unit and receive fault signals (as different voltage outputs) in an unexpected failure of the unit. This function is activated from dip switch 4 in the control box on top of the unit. Page 23 of 28

10. Maintenance Instructions Heat recovery units, by their very nature, require regular maintenance. The Duplexvent BV400 has been designed to facilitate easy access to enable maintenance to be carried out. Note: The heat exchanger will be damaged if the unit runs without the filters. WARNING THE FAN AND ANCILLARY CONTROL EQUIPMENT MUST BE ISOLATED FROM THE POWER SUPPLY DURING MAINTENANCE. 10.1 Filter Maintenance Danger Electric Shock risk In the Duplexvent BV400, both supply and exhaust air streams are filtered through G4 class course filters. The filters should always be kept in place when the ventilation unit is in operation. To prevent the contamination of this ventilation system, to guarantee years of trouble-free operation and ensure that clean air is supplied into your home the filters must be periodically cleaned or replaced (depending on contamination of the outdoor air). Step 1: Slide the service cover to the left, open it and remove the filters. Slide the Service Cover Left Open the Service Cover Remove the Filters Step 2: Use a vacuum cleaner to clean the dust from the air filter. If necessary, use warm water with detergent to remove the persistent dirt. Leave the filters to dry before placing them back in the unit. Vacuum Cleaner Filter Page 24 of 28

Note: The G4 filters should be replaced once every six months or after a maximum of two cleaning cycles. If an optional F7 filter is used please replace these filters after every maintenance cycle (replacement filters are available on www.airflow.com, see page 15 for part numbers). Step 3: Place the filters in the filter slots, close the service cover and slide it to the right to secure. 10.2 Heat Exchanger Maintenance Approximately every two years it is recommended that the heat exchanger is checked for contamination. This time scale may vary depending on the surroundings of the property. Inspection should be carried out when checking the filters. WARNING THE FAN AND ANCILLARY CONTROL EQUIPMENT MUST BE ISOLATED FROM THE POWER SUPPLY DURING MAINTENANCE. Step 1: Remove the front cover plate and the bypass module by unscrewing the screws. Danger Electric Shock risk Step 2: Remove the filters and pull the heat exchanger out gently using the green strap. Caution: The fins of the heat exchanger are very thin and can easily be damaged. Page 25 of 28

Step 3: Remove the dirt from the outside walls of the heat exchanger with a vacuum cleaner. Vacuum Cleaner Caution: Never use water or any other cleaning materials. 10.3 Other Maintenance Procedures During maintenance work in autumn please check the condensate drain is secure and not clogged. This can be tested by pouring some water into the drain pan and checking the water coming out of the unit through the condensate drain. Clean the drain, if necessary. Also ensure that the insulation of the condensate pipe is adequate. Check that the unit and all wall-mount fastenings are sufficiently tight and have not become loose. Re-tighten if necessary. 11. Accessories The following accessories for this unit can be ordered from Airflow Developments Ltd: Part Number Product Description 90000336 Digital control display 90000322 90000323 90000228 90000324 9041570 51969702 90000325 90000326 G4 filter pack (2 filters) F7 filter pack (2 filters) Boost switch (1-way) Electric duct heater (1 kw) (can be used as pre-heater or post-heater) Room humidistat PIR Motion sensor Built-in humidity sensor Pressure sensors for filter monitoring Mechanical ventilation units require good quality ducting and a high standard of installation. To ensure the best results, we recommend the innovative AIRFLEX PRO semi-rigid ducting system. Page 26 of 28

12. Troubleshooting Diagnosing a Problem In the event of a problem, always troubleshoot the unit according to LED fault. There are two types of warnings displayed on the control switch: a) Red LED f lashes on/off: Filter Maintenance Alert / Press Boost and -- for 3 seconds to reset b) Red LED flashes continuously: Failure of Components (Fans, Sensors, Heaters) c) Blue Light flashes / Fan Disabled / Press Boost and + for 5 seconds to reset Failure Reason Solution Outdoor air coming into the dwelling is cold The unit has been switched off unexpectedly The unit makes a lot of noise Water leakage near the unit Unpleasant smell near the unit Unpleasant cooking smell in the house Too much condensation in the bathroom * Air cools down in the attic ducts * The heat exchanger is frozen which is why extract air cannot heat the incoming air * The extract fan is not running * The extract air filter or the heat exchanger is clogged * Mains voltage failure Gurgling noise * Condensate trap water level is too low * Condensate pipe is not completely in the trap * Condensate pipe or condensate trap is blocked or frozen Rumbling/Rattling noise * Fan motor fault * Condensate trap is clogged or frozen * Condensate pipe has come loose * Condensate trap (U-bend) below the unit is empty * The condensate pipe is not completely in the trap * The condensate pipe or condensate trap is blocked or frozen * Air extract rates are too low * The filters are polluted/blocked * The grilles are dirty * Air extract rates are too low Page 27 of 28 Check the duct insulation If the heat exchanger is frozen contact your supplier/installer to reduce the set point of the frost protection facility Contact your supplier/installer Check that the filters and the heat exchanger are clean Consult a qualified electrician to check mains power supply to units. Fill the condensate trap with water Push the pipe deeper into the trap Check the condensate drain and clean it, if necessary Contact your supplier/installer Check the condensate drain and clean it, if necessary Fill the condensate trap with water Push the pipe deeper into the trap Check the condensate drain and clean it, if necessary Activate the boost speed when cooking Replace the filters Clean all grilles Activate the boost speed while showering or bathing

13. Warranty Applicable to units installed and used in the United Kingdom. Airflow guarantees the Duplexvent BV400 units for 3 YEARS from date of purchase against faulty material or workmanship. To be aware of the latest updates of Duplexvent BV400, please register your product at www.airflow.com. The warranty only covers the unit, not the re-installation of it if required. In the event of any defective parts being found, Airflow Developments Ltd reserve the right to repair or at our discretion replace without charge provided that the unit: 1. Has been installed and used in accordance with the fitting and wiring instructions supplied with each unit. 2. Has not been connected to an unsuitable electrical supply. 3. Has not been subjected to misuse, neglect or damage. 4. Has not been modified or repaired by any person not authorised by Airflow Developments Ltd 5. Has been installed in accordance with latest Building Regulations and IEEE wiring regulations. 6. Has been installed by a competent person who is qualified to do so. Airflow Developments shall not be liable for any loss, injury or other consequential damage, in the event of a failure of the equipment or arising from, or in connection with, the equipment excepting only that nothing in this condition shall be construed as to exclude or restrict liability for negligence. 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. This warranty does not in any way affect any statutory or other consumer rights. All information believed correct at time of going to press.