VALLOX 252 D
OPERATING PRINCIPLE OF THE VENTILATION UNIT
2
2
Silencer
Installed above the unit
Models:
VALLOX 252 D-L
VALLOX 252 D-R
VALLOX 252 D removes contaminated air
and replaces it with filtered and heated
outdoor air.
Efficient filtering of outdoor air
(EU3 + EU7) prevents harmful particles
from entering the ductwork and the rooms
via the unit. Good filtering of extract air
(EU3 + EU5) diminishes the contamination
of the unit and ensures effective operation
of heat recovery and the extract air fans.
Clogging of the supply/extract air filters
and the ductwork can be monitored if the
unit is equipped with a pressure
difference switch.
With efficient 2-step heat recovery, most
of the heat of contaminated extract air
can be transmitted to outdoor air coming
inside. The efficiency of the heat recovery
cells is approx. 70%, or 75…80% if
supply air fan heat is taken into account.
If outdoor air does not get sufficiently
warm in the heat recovery cells, it is
possible to use an (optional) heating unit
operated by water or electricity.
The unit features an automatic heat
recovery bypass function, which
eliminates needless heating of outdoor air
in the summertime. The unit also includes
an automatic defrosting function of the
water operated post-heating unit.
The automatic defrosting of the heat
recovery cells intermittently stops the
supply air fans when the temperature of
exhaust air goes under the preset
threshold value. To avoid or to decrease
the stopping of the supply air fans, you
can heat outdoor air with an electric
preheater. If the unit is equipped with a
preheater, defrosting starts when outdoor
air temperature goes below ca. -15/-
25˚C (max./min. supply air flow).
Without preheating, defrosting starts
when outdoor air temperature falls below
ca. -5˚C.
VALLOX 252 D can be controlled with the
control panel coming with the unit (3 at
most) and with optional CO
2
(5 at most)
and %Rh sensors (2 at most).
Fan speeds can be monitored remotely
with current or voltage signals. In case of
failures in the ventilation unit, a potential-
free relay point signal is received.
The optional VALLOX LON converter
allows remote monitoring based control of
the unit.
VALLOX 252 D-R
= EXHAUST AIR
= EXTRACT AIR
= SUPPLY AIR
= OUTDOOR AIR
Options
13
14
15
16
VALLOX 252 D-L
= OUTDOOR AIR
= SUPPLY AIR
= EXTRACT AIR
= EXHAUST AIR
Main Parts
Supply air fans
Extract air fans
Heat recovery cells
Heat recovery bypass
Supply air filter EU7
Extract air filter EU5
Extract air filter EU3
Outdoor air filter EU3
Condensing water reservoir
Condensing water outlet
Electrical connection
lead-throughs
Control panel
1
2
3
5
6
7
8
9
10
10
4
11
Post-heating unit
• Electric or water
Preheater
• Electric
Pressure difference switch
Carbon dioxide sensor
Humidity sensor
LON converter
12
17
18
12
15
3
2
9
6
1
4
5
8
13
14
10
11
7
187
220
222
1100
187
222
282
1370
220
(Door and insulation 55mm)
fl250 4pcs
610 +
16
17
18
A
B
C
D
A
B
C
D
A
B
C
D
*
Detachable inner coupling
*
2370
665
220
220
1100
187
222
282
222
187
1000
1370
Ø 250 4 pcs
