Any air intake terminal MUST be installed in accordance
with the appropriate regulation.
As a guide, the BS5440 series of British Standards
deals with this issue and currently states that an air
intake must be at a minimum distance of 300mm from a
gas boiler balanced flue. Installers are advised to be
aware of the requirements of this standard when
installing ‘through the wall’ supply air ducting.
Similarly, supply and extract air grilles should be
at least 300mm apart.
4.0 Outline description
The Nuaire MRXBOX90L is a highly advanced heat recovery unit,
specially designed for minimum energy consumption and maximum
comfort. This is achieved with the aid of various electronic control
systems. A control unit with microprocessor controls/monitors the
safe operation of the unit and ensures that the air quantities remain
constant, and at the preset values. MRXBOX90L units incorporate a
control panel with display, enabling stepless adjustment of the volume
without having to open the unit. Moreover, information regarding the
operation can be read out from the outside of the unit.
4.1 LED display system and
operating panel
The MRXBOX90L control panel positioned on the front panel of the
unit can be used to retrieve and modify the settings in the control unit
program.
The control panel has four keys and a display.
1. = Display
2. = Key “OK” (confirm, ready)
3. = Key increase parameter
4. = Function key
5. = Key decrease parameter
On the left the display indicates the ventilation setting or the
parameter type. on the right it shows the readout value, for instance
the preset volume.
Example:
The display now shows ( figure 5) that the unit is running at
ventilation setting 3 at a flow rate of 280 m
3
/h.
The four keys have the following functions:
•
F
Function key/switching on and off parameter menu
•
+
next parameter/increase value
•
-
previous parameter/decrease value
•
OK
Switching on and off settings menu/manual fault reset
Other commands can be entered with key
combinations:
•
F
and
+
(set), confirm parameter value
•
F
and
-
(reset), reset filter indication, parameter value back to
factory setting
•
OK
and
+
(ON), switch on unit
•
OK
and
-
(OFF), switch off unit
This applies throughout this manual when a key has to be pressed,
The key in question is printed in quotation marks and in bold.
Example: - press key
“OK”.
4.2 Bypass conditions
The bypass, makes it possible to supply fresh outside air that is not
heated by the heat exchanger. This can be desirable during summer
nights when the hot air in the dwelling can be replaced by cooler
outside air. The bypass damper opens when the interior temperature
exceeds an adjustable temperature (standard 22°C) and when the
outside air is warmer than an adjustable temperature (standard 10 °C)
but colder than the interior air.
Outside air supplied through the bypass is still being filtered, so the
air quality is optimal, irrespective of the bypass setting.
The installer can set the bypass for different situations at adjustable
parameter 8.
4.3 Frost safety
The frost protection system ensures that the secondary side of the
heat exchanger (outlet side) does not freeze up by introducing an
imbalance between the inlet and outlet air flows, dependent on the
outside air temperature and the pressure across the heat exchanger.
Under severe conditions the inlet air flow will shut down. NB:
Settings are not adjustable.
4.4 Filter indication
The unit is fitted with a filter indication system. It indicates on the
display when the filter is fouled. For more detailed information refer
to section 9.
3
Leaflet Number 611272 January 2012
Installation and Maintenance
MRXBOX90L Mechanical Ventilation with Heat Recovery
1
2
3
4
5
Figure 4. Control panel
Figure 5.
