NuAire MRXBOXAB-ECO4 Instruction Manual

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nuaire.co.uk 029 2085 8400 19. 08. 19. Leaflet Number 671797
MRXBOXAB-ECO4 (Standard Unit)
MRXBOXAB-ECO4-OH (Opposite hand Unit)
Mechanical Ventilation Units with Heat Recovery and
Heat Exchanger Bypass for Wall Mounting
Installation and Maintenance
The EMC Directive
2014/30/EU
The Low Voltage
Directive
2014/35/EU
1.0 Introduction
The ECO4 wall mounted units are designed to provide mechanical
supply and extract ventilation with heat recovery and an integral
automatic HX bypass.
The units also incorporate an integral humidistat and frost protection
(see page 7 for details).
To recover heat from the extract air the heat exchanger block is utilised.
The heat exchanger can recover up to 95% of the normally wasted
heat.
2.0 Installation
Installation must be carried out by competent personnel in accordance
with the appropriate authority and conforming to all statutory
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.
Please note a clear working space is required around the installed unit
to allow the cover to be removed and provide sufficient access for
maintenance such as filter change.
Please allow a minimum of 480mm in front of the unit.
The fan must be installed indoors, on a suitable wall away from direct
sources of frost, heat and water spray or moisture generation. For a
vibration-free result the unit must be mounted to a solid wall.
The unit is designed for wall mounting only on a solid wall, a
gypsum block or a stud wall will not suffice. Additional measures
such as extra studs or double panelling using 20mm MDF is
required.
1. One part of the mounting bracket (supplied) should be offered up
to the wall, ensuring it’s located horizontally. Mark the fixing points
through the pre drilled holes in the bracket and install with screws (by
others), whilst ensuring the interlock side is at the top (fig. 3).
2. Install the unit on the wall by ensuring the bracket on the unit
interlocks over the wall mounted bracket (fig. 4). Ensure the mains
power cable does not become trapped between the brackets during this
process as this will prevent engagement and potentially damage the
electrical insulation. The cable gland can be rotated through 90 degrees
to assist this operation and subsequent cable routing.
IMPORTANT
The unit must remain switched on at all times to maintain
ventilation within the dwelling. Turning the unit off will cause long
term damage to the unit and building fabric.
This appliance is not intended for use by persons (including children)
with reduced physical, sensory or mental capabilities, or lack of
experience and knowledge, unless they have been given supervision
or instruction concerning the use of the appliance by a person for their
safety. Children should be supervised so that they do not play with
the appliance.
Note: Care must be taken to ensure the unit is installed true in
all 3 dimensions. Failure to do so may result in overflow from the
internal condensation drip tray.
If fitting the MVHR in conjuntion with a MRXBOX-SIL4 the unit
should be mounted using alternative brackets supplied under part
code MRXBOX-AV4, the standard wall brackets supplied with the
MVHR are not rated for the additional load.
Extract air
from house
Intake air
from outside
Exhaust air
to outside
from house
Supply air
to house
Exhaust air
to outside
from house
Supply air
to house
Extract air
from house
Intake air
from outside
Figure 1. Airflow through unit (Standard unit).
Figure 2. Airflow through OH unit (Opposite hand unit).
Figure 3. Fixing the mounting bracket to the wall.

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nuaire.co.uk 029 2085 8400 19. 08. 19. Leaflet Number 671797
Installation and Maintenance The ECO4 Wall Mounted Range of Units
2.1 Option 1: Wall Mounting
The MVHR unit fixed to a solid wall construction using the
mounting bracket provided.
2.2 Option 2: Wall Mounting
If it is not practical to use a solid wall, the MVHR unit should be
fixed to a stud partition with a 25mm minimum thickness MDF
panel solidly fixed behind the plasterboard.
If fixing to a stud wall the MDF panel should extend, width wise, over a
minimum of 3 vertical studs with centres of no more than 400mm. Add
additional vertical supports if necessary.
Height wise, ideally, the MDF panel should extend from floor to ceiling
but as a minimum should be a least 2m high.
Fix the mounting bracket to the wall (as fig. 3) and use the wall
mounted bracket to mount the unit on (as shown in fig. 5).
Ducting in the
ceiling void.
Side view of unit
mounted on the
block wall in a
cupboard.
MVHR-DRAIN
Condensate drain,
uninsulated drain
pipe with min 5 o
fall running to SVP.
Valve in ceiling.
Figure 4. Typical example of a cupboard mounted unit (Standard
unit) fixed to a block work wall.
Ducting in the
ceiling void.
mounted in a
Side view of unit
a stud partition
cupboard fixed to
with the 25mm
MDF fixed behind
MVHR-DRAIN
the plasterboard.
Condensate drain,
uninsulated drain
pipe with min 5 o
fall running to SVP.
Valve in ceiling.
Figure 5. Typical example of a cupboard mounted unit (Standard
unit) fixed to a stud partition with the MDF panel fixed behind the
plaster-board.
2.3 Condensate Drain
1. The condensate must be discharged under a water level in a U-trap
drainpipe or an alternative drain method which acts as an airlock.
2. The condensate discharge drain is a 32mm male threaded
connection.
3. If using a U-trap please ensure the U-trap has been filled to a
suitable level of water to avoid any air locks.
4. If the condensation pipe is fitted in an unheated space the pipe
should be in insulated to prevent freezing.
Nuaire recommend MVHR-DRAIN be used as the primary
condensate take-off. (see figure 10 and 11).
Min 5o Drop
Collar
Figure 6. Wet option:
Condensate pipe connection
to unit and a typical
example of a “U” trap
drainpipe (Standard
configuration only).
Figure 7. MVHR-DRAIN option: Condensate
drain, uninsulated drain pipe with min 5° fall
running to SVP.
To SVP
“T” piece
MVHR Drain
To unit
To CONTRAP
Figure 8. IMPORTANT: When using a “T” Piece to connect the
CONTRAP drainage and the MVHR drain pipework the MVHR
drain must always be fitted before the “T” Piece to prevent
condensate from feeding back into the MVHR system.
2.4 Extract/Input Areas
The unit is designed to extract air from all wet rooms e.g. bathroom,
kitchen, en-suite, utility room (with sink). WC’s do not need to be
ventilated if openable windows are fitted.
Supply air should be to all habitable rooms e.g. bedrooms and lounge.
Extract / input grilles should be adjustable valve types (not supplied).
External grilles are to have a minimum free area of 12,250 sq. mm.

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nuaire.co.uk 029 2085 8400 19. 08. 19. Leaflet Number 671797
Installation and Maintenance The ECO4 Wall Mounted Range of Units
Table 1. ADF 2010 - Extract ventilation rates.
Table 2. Whole dwelling ventilation rates.
Notes:
1. In addition, the minimum ventilation rate should be no less than
0.3 l/s per m2 of internal floor area. (This includes all floors, e.g.
for a two-story building add the ground and first floor areas).
2. This is based on two occupants in the main bedroom and a single
occupant in all other bedrooms. This should be used as the default
value. If a greater level of occupancy is expected add 4 l/s per
occupant.
IMPORTANT
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.
Room Min high rate Min low rate
Kitchen 13 l/s
Total extract rate
should be at least
the whole dwelling
ventilation rate given
in table 2.
Utility Room 8 l/s
Bathroom 8 l/s
Sanitary
Accommodation
6 l/s
Number of bedrooms in dwelling
1 2 3 4 5
Whole dwelling
ventilation rate l/s
1,2
13 17 21 25 29
2.5 Ducting
It is recommended that rigid ducting be used it all times. Flexible
ducting has a very high resistance and it is impossible to calculate how
much resistance will be on a system if used.
If used, the flexible ducting must be kept to a minimum and should
always be pulled taut. A maximum of 300mm should be used on each
leg.
To prevent condensation on the exterior of the outside air inlet duct
and the air outlet duct from the unit, these ducts should be insulated
with material having a thermal resistance of >0.625m2 K/w.
Ducting must be installed in such a way that resistance to airflow is
minimised. Bends should be kept to a minimum.
A minimum distance of 200mm between the appliance and any bends
in ductwork is recommended. Ideally 200mm diameter or 204 x 60mm
rectangular ducting should be used.
Ducting joints must be sealed with silicone type sealant and shall be
adequately and reliably fixed to the appliance.
2.6 Ventilation Flow Rates
2.7 ADF 2010 Ventilation Calculations Design of MVHR
Systems
The MVHR system has been sized for the winter period. Additional
ventilation may be required during the warmer months and it has
been assumed that the provisions for purge ventilation (e.g. openable
windows) could be used.
Step 1: For any design air permeability, determine the whole dwelling
ventilation supply rate from Table 2.
As an alternative where the design air permeability is intended to be
more than (>) 5m3/(h.m2) 50 Pa, allow for infiltration for all dwelling
types by subtracting from the whole dwelling ventilation supply rate
from Table 2; 0.04 x gross internal volume of the dwelling heated
space (m3).
Step 2: Calculate the whole dwelling extract ventilation rate by
summing the individual room rates for ‘minimum high rate’ from Table
1.
(For sanitary accommodation only, as an alternative, the purge
ventilation provisions given in ADF 2010 can be used where security is
not an issue. In this case ‘minimum high extract rate’ for the sanitary
accommodation should be omitted from the step 2 calculation).
Step 3: The required airflow rates are as follows:
•The maximum whole dwelling extract ventilation rate (e.g. boost)
should be at least the greater of step 1 and step 2. Note that the
maximum individual room extract rate should be at least those
given in table 1.
•The minimum air supply rate should be at least the whole building
ventilation rate found in step 1.
For Scotland refer to BRE Digest 398.
For further information refer to “Domestic Ventilation Compliance
Guide” www.planningportal.gov.uk/buildingregulations/approved
documents/partl/compliance
Pre Commissioning MRXBOX95 MVHR Units
MRXBOX95 units are designed to ventilate the whole dwelling
and must not be used during site construction or the clean-up
period. Cement and plaster dust can be abrasive and can affect fan
performance and reliability. Please ensure that the filters are checked
prior to commissioning to ensure there is no build-up of dust or debris.
While the property is drying out, very high moisture levels are likely
to occur. Therefore it is advisable that if the installation and building
works are complete the unit is left running. If the building works are
not complete please close the air valves or cover up the air valves to
prevent condensation forming in the ductwork and the MRXBOX95 unit
due to natural migration of warm air.

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nuaire.co.uk 029 2085 8400 19. 08. 19. Leaflet Number 671797
Installation and Maintenance The ECO4 Wall Mounted Range of Units
290 139
485
710
710 585
Ecosmart connection
4 x Spigots
180mm Internal Diameter
200mm External Diameter
View from top
Side view
Front view
18
Mounting Bracket
= =
AB
AB
= =
200
176
534
67
492 CRS
67
40.0 CRS
5 Fixing
Points be fitted to
Bracket to
Volt Free Cable
Exit Point
Main Cable
Exit Point
the wall
40.0 CRS
86.0
Front view Side view
86.0
15.0
23.0
Flush mounting face to
wall or back box
25 25
Figure 9. Unit dimensions.
3.0 Dimensions (mm)
Figure 10. Dimensions: MRXBOX95-3SWITCH Figure 11. Dimensions: Unit wall mounting bracket
position (viewed from the back).

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nuaire.co.uk 029 2085 8400 19. 08. 19. Leaflet Number 671797
Installation and Maintenance The ECO4 Wall Mounted Range of Units
4.0 Ducting Arrangements - Standard Configuration
Figure 12. Typical ducted arrangement for a wall mounted unit using circular ducting.
Figure 13. Typical ducted arrangement for a wall mounted unit using circular ducting.
Air supply
to lounge
in ceilings.
via Air Valve
Extract air
from
kitchen/
bathroom
in ceilings.
via Air Valve
Exhaust air from
kitchen/bathroom to
outside via louvre grille.
Minimum distance as specified
in building regulations.
Intake air
from outside
via louvre grille.
All duct between MVHR
unit and atmosphere to
be insulated*.
*Insulated
supply duct.
Top of ceiling void.
Air supply to
bedrooms
in ceilings.
via Air Valve
mounted unit.
Nuaire wall
MVHR-DRAIN
Condensate drain, uninsulated
drain pipe with min 5
o
fall running to SVP.
*Insulated
extract duct.
New
ALSO FROM NUAIRE -
range of thermal ducting,
an all-in-one insulated ducting system
(see installation document 671780)
Exhaust air from
kitchen/bathroom to
outside via air brick.
Minimum distance as specified
in building regulations.
Intake air
from outside
via air brick.
All duct between MVHR
unit and atmosphere to
be insulated*. *Insulated
supply duct.
Air supply
to lounge
in ceilings.
Extract
via Air Valve air from
kitchen/
bathroom
in ceilings.
via Air Valve
Air supply
to bedrooms
in ceilings.
via Air Valve
Top of ceiling void.
mounted unit.
Nuaire wall
MVHR-DRAIN
Condensate drain, uninsulated
drain pipe with min 5ofall running to SVP.
*Insulated
extract duct.

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nuaire.co.uk 029 2085 8400 19. 08. 19. Leaflet Number 671797
Installation and Maintenance The ECO4 Wall Mounted Range of Units
5.0 Electrical Connection
IMPORTANT
For good EMC engineering practice, any sensor cables or
switched live cables should not be placed within 50mm of other
cables or on the same metal cable tray as other cables.
Please note: the electrical connection of the unit
must be be carried out by a qualified electrician.
The unit is supplied with a flexible cord for
connection to the mains supply.
Electrical details:-
Voltage: 240V 1ph 50Hz
Consumption: 2.5 Amp
Fuse rating: 5 Amp
NOTE This unit must be earthed.
The three core cable from the mains power
supply should be connected to a fixed wiring
installation, via a fused isolator, in accordance
with current IEE wiring regulations.
5.1 Examples of typical wiring layouts
MAINS
230V
50Hz N
L
3 Position Switch Ancillary code:
MRXBOX95-3SWITCH
Blue
Green/yellow
Brown
Black
Supply cord
from unit
Grey
L
1
2
Fuse 5A
MAINS
230V
50Hz N
L
3 Pole
Isolator
3 Position Switch Ancillary code:
MRXBOX95-3SWITCH
Blue
Green/yellow
Brown
Black
Supply cord
from unit
Grey
L1
2
Fuse 5A
2 Pole
Isolator
light
Room
Light
switch
(Double
Pole)
MAINS
230V
50Hz N
L
3 Pole
Isolator
3 Position Switch Ancillary code:
MRXBOX95-3SWITCH
Blue
Green/yellow
Brown
Black
Supply cord
from unit
Grey
L1
2
Fuse 5A Room
lights
Light
switches
(Double
Pole)
MRXBOXAB-ECO4
Figure 15. Unit only.
Disconnection from the supply mains must be
incorporated within the fixed wiring in accordance
with the wiring regulations and shall have a minimum
contact separation of 3mm.
MRXBOXAB-ECO4
Figure 16. Unit serving one bathroom.
Disconnection from the supply mains must be
incorporated within the fixed wiring in accordance
with the wiring regulations and shall have a minimum
contact separation of 3mm.
MRXBOXAB-ECO4
Figure 17. Unit serving two bathrooms.
Disconnection from the supply mains must be
incorporated within the fixed wiring in accordance
with the wiring regulations and shall have a minimum
contact separation of 3mm.
EXTRA
EXTRA
CT F
CT F
AN
LIAF
Supply Extract Supply Extract Supply Extract
SPEED 1 SPEED 2 SPEED 3
3
2
If more than one Ecosmart
sensor is required please
use MRXBOX-JB and refer
to leaflet No. 671700 for
installation instructions.
Note: Wiring is for reference
purposes only as the
connections above are
factory fitted.
Connection to Remote Fail
Indicator Ref: MRXBOX95-RFI
(optional).
Figure 14. PCB Details

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nuaire.co.uk 029 2085 8400 19. 08. 19. Leaflet Number 671797
Installation and Maintenance The ECO4 Wall Mounted Range of Units
+ -
Post commissioning remove
adhesive backing and seal
061021
Power Fan
Failure
+ -
Ventilation Controls
-
+
+
-
+
-
Speed 1
-
+
Speed 2 Speed 3
Supply Extract Supply Extract Supply Extract
IMPORTANT
The filters fitted inside the unit are protected with a plastic film.
Prior to commissioning remove the covers (figs. 15 & 16), take off the
film and replace.
1. For required air flow rates please refer to the design specification for
the property, follow 2.4 or refer to building regulations
ADF 2010.
2. The unit should be run for a minimum of 10 minutes to reach steady
state before commencing commissioning.
3. The humidity sensor is initially set to its least sensitive position, this
should be adjusted during commissioning. Depending on storage
and site conditions the unit may boost due to high relative humidity
levels, this will continue until the level drops below the specified set
point.
4. The unit is supplied with independent control for the various speed
airflows. (see fig. 19).
HX Bypass
(AB units only)
Speed 1
Speed 2
Speed 3
Supply Fan Fault
Extract Fan Fault
Frost Protection
Filter Change
5. Correct commissioning is essential to ensure the ventilation air flow
rates are met. It also ensures the unit is not over ventilating and
causing excessive power consumption.
6. Commissioning should be carried out in accordance with building
regulations document “Domestic ventilation compliance guide”.
www.planningportal.gov.uk/building regulations/approved
documents/partf/associated
A calibrated moving vane anemometer and hood will be required to
carry out commissioning.
7. Adjustment valves should be locked in place to prevent further
adjustment.
8. Once commissioned the home owner / tenant should be informed
that the unit should not be adjusted as it will have a detrimental
effect on the indoor air quality and could result in condensation and
mould growth. The clear panel covering the control has an adhesive
panel which should be exposed and sealed post commissioning to
prevent tampering.
6.0 Switch
To fix the switch to a wall or back box remove the front fascia by
inserting a terminal screwdriver into the two openings along the
bottom edge and prize open gently. The fixing points on the back plate
can then be accessed; once the switch has been secured the front fascia
can then be re-fitted.
6.1 Ecosmart controls
A single Ecosmart sensor can be connected to the unit using the
connector situated on the rear panel (see fig. 9). If more than one
Ecosmart sensor is required please use MRXBOX-JB and refer to leaflet
No. 671700 for installation instructions.
7.0 Commissioning
7.1 Humidity adjustment.
This product contains an internal humidity sensor fitted into the air-
flow extracting from the wet rooms. When the unit senses that the
humidity exceeds the set point the unit will boost to that set by the
commissioned boost speed. The set point can be found on the front
of the unit (see fig. 9) and is at its least sensitive when turned fully
clockwise. Note that the sensor is measuring humidity from all the wet
rooms at the same time and should not be relied on to solely boost the
unit.
Additional switch should be used local to the wet rooms (see wiring
diagrams).
8.0 Status Indication
The status of the unit is indicated by a series of LED’s on the front cover.
The variants are listed below.
8.1 Integral automatic HX bypass (AB units only)
Intake and extract temperatures are monitored at the point the
airflows enter the unit, if the range falls within the set parameters the
bypass damper is opened automatically to target an indoor comfort
temperature all year round.
Note: The extract temperature is an average from all wet rooms. If
this exceeds 25°C the unit may go into bypass depending on outside
temperatures.
Figure 18. Ecosmart
sensor connector on the
rear panel of the unit.
Figure 19. Detail of unit control
on front panel.Note: The display on the unit control panel will not indicate when a
higher speed setting has been triggered by an external source, such
as an ES-PIR2 etc.

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nuaire.co.uk 029 2085 8400 19. 08. 19. Leaflet Number 671797
Installation and Maintenance The ECO4 Wall Mounted Range of Units
Telephone [phone]
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10.0 Replacement of Parts
Should any component need replacing, Nuaire keep extensive stocks
for quick delivery. Ensure that the unit is electrically isolated, before
carrying out any work.
Note: The supply cable must be replaced by an electrically competent
person.
When ordering spare parts, please quote the serial number of the unit
and the ARC number of the purchase, if possible. (This information will
be available on the fan label).
Nuaire recommend that filters are inspected every 6 months and
replaced every 12 months. A flashing LED (section 8.0) will indicate that
a filter change is required. This indication repeats every 12 months and
will turn off automatically after 5 Days.
Remove the filter covers on the front panel of the unit by gripping the
two circular tabs either end of the filter covers and pulling away from
the unit. The filter can now be extracted by pulling the removal loop on
the front edge of the filter. Once the filters have been inspected return
or replace them as necessary.
Inspect the heat exchanger every 5 years. Generally check for damage
and security of components. Refit cover.
9.0 Maintenance
IMPORTANT
Isolation - Before commencing work make sure that the unit,
switched live and Nuaire control are electrically isolated from the
mains supply and switched live supply.
Filter covers
Filter being
removed
Filter cover
Figure 20. Removing the
two filter covers on the front
panel of the unit.
Figure 21. The filters can be
removed by pulling on the
black tab on the visible end
of the filters.
12.0 After Sales
For technical assistance or further product information, including spare
parts and replacement components, please contact the After Sales
Department.
8.2 Frost Protection
In the event of the intake air temperature at the unit dropping below
the predetermined set point (-5° C as standard) the supply fan will
reduce to minimum speed, once the temperature rises above the set
point the fan will return to its commissioned speed.
Please note this mode will only activate after ten days of continuous
run time. If commissioning of the unit is outside of this time frame
please notify the after sales department prior to site visit.
11.0 Warranty
The 5 year warranty starts from the day of delivery and includes parts
and labour for the first year and parts only for the remaining 4 years.
This warranty is void if the equipment is modified without
authorisation, is incorrectly applied, misused, disassembled, or not
installed, commissioned and maintained in accordance with the details
contained in this manual and general good practice.
The product warranty applies to the UK mainland and in accordance
with Clause 14 of our Conditions of Sale. Customers purchasing from
outside of the UK should contact Nuaire International Sales office for
further details.