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Airflow Duplexvent BV400 Heat Recovery Unit 90000660

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Airflow Duplexvent BV400 Heat Recovery Unit 90000660
£962.40 including VAT Excluding VAT £802.00
Airflow Duplexvent BV400 Heat Recovery Unit - 90000660


Airflow BV400 Heat Recovery Unit - 90000660

Very popular and cost efficient Heat recovery unit from Airflow with Automatic Summer Bypass and hard wired controller  

Ideal for developers and home builders requiring a quality unit at economical cost  

  • Up to 93% Heat recovery
  • Built in humidity sensor
  • 425m3/h @100pa suitable for houses with Max floor area of 250m2
  • Specific fan power as low as 0.45 wls
  • EC motors
  • 3 speed hard wired controller
  • Summer Bypass  
  • 100% Adjustable air flow rates
  • G4 (standard) to F7 (optional) pollen filter options
  • Frost protection
  • Multiple control options
  • SAP Appendix Q listed
  • Left to right ductwork configuration possible
  • 3 year warranty
  • Developed and manufactured in th UK
Technical Specification

Technical Specification tab

Technical Specification

  • Up to 93% Heat recovery
  • Digital control panel
  • Internal humidity sensor
  • Max Air flow 475 - 425 m3/h @100pa
  • suitable for houses with Max floor area of 250m2
  • Kitchen plus 7 extraction points 
  • Specific fan power as low as 0.45 wls
  • Dimensions WxHxD (mm) 710x725x630
  • Duct Diameter 4 x160mm
  • weight 41kg
  • Filtration 2xG4
  • 100% Summer Bypass  
  • Sound level 23 to 41 @3m db(a)
  • Wall mounted
  • Frost protection  
  • 100% Adjustable air flow rates via digital control panel
  • Multiple control options
  • SAP Appendix Q listed
  • 3-year warranty (excludes motors)
  • Developed and manufactured in the UK
  • Counterflow heat exchanger (PVC)
Download Documentation
Airflow BV400 Catalogue
Airflow BV400 Installation instructions
Airflow BV400 Controller operation
Further Information

How to install a Airflow BV400 using a radial duct-work system

Initial Design -

Pre designed plan - Please follow the plan ensuring the correct number of pipes to each area - Please note the plan is only a guide and you may have to reroute pipe work differently and reposition valves to suit layout of rooms

No Plan - If a design is not possible due to renovation, Retrofit or properties with multiple obstacles simply follow the listed recommendations

We would recommend that you

  • Install 2 x pipes from the distribution box to the room air plenum if air flow requirement exceed 10 L/s or if length over 15 meters  

  • Install 2 x pipes from the distribution box to the air extract plenum in the main shower rooms and Kitchen

  • All other areas only require a single pipe from the distribution box to the room air plenum

  • Radial ductwork is suitable to be fitted below your loft insulation providing superior heat retention Insulate any ductwork or Manifold/ Distribution boxes with a minimum of 25mm thermal duct wrap that go above insulation in unheated attic spaces

  • Slim-line manifolds are suitable for installation to concrete ceilings and only require a 100mm service void

  • Position supply plenums approx. 500mm from corner of wall (avoid areas above beds and wardrobes)

  • Position extraction plenums to outside of showers and above kitchen sink (not cooker)

  • Only extract from a room with a open appliance (stove) if there is a supply with equal or higher airflow

Installation Guide

1st Fix

  1. Position unit proverbially on a wall or vertical timber frame with provided wall bracket

  2. Install wiring for controllers (see bottom of page for further details)

  3. Install condensation drain from unit to internal or external drain

  4. Install wall /Soffit vents or roof vents (Minimum 1.5 meter apart) Pipes are 125mm diamater

  5. Position distribution boxes in the chosen location (proverbially in a central location minimising duct lengths )

  6. Install silencer (if specified) to air supply distribution box

  7. Install solid rigid duct-work and between distribution boxes and MVHR unit, (If possible allow for insulated flexible duct-work for final connections of MVHR unit )

  8. Install radial pipe into the distribution box ,

  9. Cut to length and install pipe into ceiling plenum, (insure you install rubber seal onto pipe) secure pipe in place with fixing band or pipe clips

Warning! There can be either one or two pipes going from the distribution box to the plenum depending on the required airflow , Always check plan that will indicate 1 or 2 pipes Install insulated rigid or insulated flexible ductwork to external vents Seal all open pipes to prevent debris and moisture ingress


2nd fix

  1. Trim ceiling Plenums to height of plasterboard (Easier to do before plastering ceilings)

  2. Install air valves to plenums (slightly open valve by two turns)

  3. Install all controllers

  4. Check that condensation drain has been fitted

  5. Switch unit on and follow the set up procedures

  6. Check air flow rates and commission system

Wiring Requirements

  • 3amp switched spur beside unit

  • A optional boost switch can be wired to the unit- install a 4 core 1mm cable from unit to single box outside bathrooms, we have various options on our website under controllers

  • 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 

  • * 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.

  • * 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..


  • 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 (do not force or over adjust)

  • Control Switch Potentiometer for Low Speed Medium speed will be set automatically by the controller's software taking the mid-point of the High and Low fan speed settings. 


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