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Leaflet Number 671366 July 2007
Installation and Maintenance
mrXbox90S Mechanical Ventilation with Heat Recovery
5.0 Installation
Installation must be carried out by competent personnel in
accordance with the appropriate authority and conforming to all
statutory and governing regulations.
All mains wiring must be in accordance with the current I.E.E.
Regulations, or the appropriate standards.
Ensure that the mains supply (Voltage, Frequency and Phase)
complies with the rating label. It is recommended that the connection
to the unit is made with flexible cable.
The unit must be fitted indoors, away from any direct sources of heat,
water spray or moisture generation.
The units condensate drain must be connected to the building foul
water drainage system.
If an extract grille associated with the unit is sited in a room containing
a fuel burning unit, the installer must ensure that air replacement is
adequate for both units. Also ensure that the units external grilles are
located at least 600mm away from any flue outlet.
If the ductwork passes through an unheated loft void or similar
location, it should be insulated.
Certain applications may require the installation of sound attenuation
to achieve the sound levels required.
Unit installation procedure can be summarised as
follows:
1. Placing the unit (5.1)
2. Connecting the ducts (5.2)
3. Connecting the condensate discharge (5.3)
4. Electric wiring diagram:
connecting the multiple switch and, if necessary, the power
supply (5.4)
The mrXbox90s must be installed in accordance with:
• the regulations for ventilation of dwellings and residential
buildings
• the safety regulations for low-voltage installations (current
IEE regulations)
• the regulations for connection to interior sewers in dwellings
and residential buildings
• any additional regulations of the local utilities
• the installation instructions for the mrXbox90s
5.1 Placing the unit
The mrXbox90S can be directly mounted to the wall using the
suspension strips supplied for that purpose. For a vibration-free
result the unit must be mounted to a solid wall with a minimum mass
of 200kg/m
2
. (NB: a gypsum block or metal stud wall does not
suffice. Additional measures such as double panelling or extra studs
are required).
• the unit must be placed level
• the installation room must be such that a good condensate
dis charge with air trap and pitch for condensate can be made
• the installation room must be frost-free
• make sure there is a free space of at least 70cm at the front of
the unit and a free headroom of 1.8m for cleaning the filters
and carrying out maintenance
5.2 Connecting ducts
The air outlet duct does not have to be fitted with a control valve; the
unit itself controls the air quantities.
To prevent condensation on the outside of the outside air inlet duct
and the air outlet duct from the mrXbox90S, these ducts must be
insulated externally vapour-proof as far as the unit.
Pay attention to crosstalk and installation noise, also for incorporated
ducts. Design the duct with separate branches to the valve to prevent
crosstalk. if necessary, the input ducts must be insulated, for instance
when they are installed outside the insulated shell.
The duct must always have an adequate diameter, of 150mm for air
quantities up to 250 m
3
/h, a diameter of 160mm for air quantities up
to 325 m
3
/h and a diameter of 180mm for air quantities up to 400
m
3
/h. The duct spigots of the unit are fitted with loose sealing rings
160mm diameter.
Figure 6. A duct diameter of 125mm is recommended.
