Unit must not be switched off, product is
designed to run continuously.
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.
Isolation - Before commencing work make sure that the unit,
switched live and Nuaire control are electrically isolated
from the mains supply. Note this product must be earthed.
Carry out all required electrical connections before fitting
the front section.
3
Leaflet Number 671365 October 2009
Installation and Maintenance
mrXbox70 Mechanical Ventilation with Heat Recovery
4.0 Electrical Wiring
The unit is designed to be wired directly to the mains supply
through a fused spur isolator (by others). With the rear
section only fixed in position bring the mains wiring through
the supplied cable gland (this gland can be moved to the
side position if required).
Additional grommeted holes are provided to allow additional
wiring to each blower.
The two fans are pre-wired into an internal wiring block for
ease of connection. (see figure 9 for connection details).
All incoming mains connections must be routed through a
suitable local isolator for maintenance purposes.
L
N
Fuse 3A max.
230V ac
signal
must be
routed
through
isolator
2
1
L
N
E
Signal to
activate
supply fan
Signal to
activate
extract fan
230V
50Hz
mains
supply
Isolator (by others)
Figure 9. Terminal Block Connections.
5.0 Setting to Work
Each fan is factory set to operate at trickle airflow when
power is applied and switch over to the boost flow rate
when a switched live signal is present. The pot marked ‘MIN
Airflow’ adjusts the trickle flow rate and the boost flow rate
by the pot marked ‘MAX Airflow’. These flow rates for the
supply and extract fan are adjusted separately. When the
switched live signal is removed, the fan will continue to run
at boost flow rate for a preset period as dictated by the pot
marked ‘RUN-on’.
6.0 Run-on Timer
The Run-on timer adjustment is from 0 - 60 mins.
Run-on is
only available from the switched live (SL) signal.
7.0 Maintenance
It is inevitable that even with filtered extract grilles as
recommended in BRE digest 398 some dust, fluff etc. will
pass through the filter, and which, if allowed, will build up
internally on motors and impellers, shortening the life of
the unit and, in severe cases, leading to overheating of the
motors. Consequently, it is strongly recommended that all
units are inspected and cleaned every 18 months.
8.0 Cleaning
Remove covers and carefully clean out interiors as
necessary. To clean the filters, remove from the unit and
vacuum clean or wash in tepid water to which a little
detergent has been added. Shake out excess water and
allow to dry naturally. Replace when dry. The heat exchanger
core can be safely cleaned in a domestic dish washer.
Check for damage and security of components. Refit covers.
9.0 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.
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).
10.0 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 conditional on
planned maintenance being undertaken.
11.0 Service Enquiries
Nuaire can assist you in all aspects of service. Our service
department will be happy to provide any assistance required,
initially by telephone and If necessary arrange for an
engineer to call.
Customer Services Department
on 08705 002 555
N
L
SL
Do not use
To OPUS-SPD
speed control
Internal
humidity adj.
To remote
fail indicator
ES-MEV-AVI
TEST
Status
30
0
60
Run-on
(mins)
25
100
Max
Airflow
(%)
25
100
Min
Airflow
(%)
LVT
NET
TR
240V 1ph
supply
pre-wired
to terminal
box
Switch live
input
pre-wired
to terminal
block
(Terminal 1 for extract fan)
(Terminal 2 for supply fan)
4.1 Additional Control Wiring Option
Other control wirings are available on each fan. Open the
cover of the unit to gain access to these connections on
each fan (see figure 10).
Figure 10.
