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nuaire.co.uk
029 2085 8400
04. 11. 19. Leaflet Number 671859
Installation and Maintenance
MRXBOXAB-ECO2-AESW Mechanical Ventilation Unit with Heat Recovery
2.9 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
70 6
1
1
6
448
55
172 CR S
144
417 CR S
=
=
Ø125.0
UNIT WEIGHT = 45Kg
if ancillary distribution box (DB-ECO2) is to be used refer to documentation
supplied with DB-ECO2 as requirements will differ.
142
142
N
N)
Condensate drain
connection
(opposite hand
configuration)
Condensate drain connection
on centre line of unit
Condensate drain
connection (standard
configuration)
Figure 11. Unit dimensions.
3.0 DIMENSIONS (mm)
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.
