VALLOX 252 M
OPERATING PRINCIPLE OF THE VENTILATION UNIT
Sound
attenuator unit
2
2
Installed above the unit
Models:
VALLOX 252 M L
VALLOX 252 M R
VALLOX 252 M 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
rooms via the unit. Good filtering of discharge air (EU3
+ EU5) diminishes the contamination of the unit and
ensures effective operation of heat recovery and the
discharge air fans. Clogging of the filters and the duct-
work can be monitored if the unit is equipped with
pressure difference switches.
With efficient 2-step heat recovery, most of the heat
of contaminated discharge 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.
In the summertime, needless heating of outdoor air
can be avoided with the heat recovery bypass function,
operated either manually or by remote control.
The automatic defrosting of the heat recovery cells in-
termittently stops the supply air fans when the tempe-
rature of discharge air goes under the pre-set threshold
value. To avoid or to decrease the stopping of the supp-
ly air fans, supply air can be heated with an electrical
preheater. If the unit is equipped with a preheater, def-
rosting starts when outdoor air temperature goes be-
low ca. -15/-25
°
C (max./min. supply air stream). Wit-
hout preheating, the operation starts when outdoor air
temperature falls below ca. -5
°
C.
VALLOX 252 M can be operated with the manual cont-
rol unit contained in the delivery. With the manual
control unit, you can select the min. or max. ventilation
power, and stop the unit. The control unit also features
a heat recovery bypass switch. The manual control unit
cannot be used in remote monitoring control.
In remote monitoring, you can stop the unit, and adjust
three different power positions (min, half, max). Heat
recovery bypass can also be controlled in remote mo-
nitoring. Control voltage in remote monitoring is 24
VAC.
The unit gives potential-free signals of operation mo-
des of the selected power positions and the optionally
installed pressure difference switches of the ductwork.
The unit can supply control voltage (24VAC) to separate
damper motors of the outdoor air and extract air ducts.
This control voltage is switched off when the unit is
stopped. The function can be used in both manual and
remote monitoring control.
The separate damper motors are not included in the
delivery.
2370
665
220
220
1100
187
222
282
222
187
1000
1370
Ø 250 Pcs.
VALLOX M 252-R
= EXTRACT AIR
= DISCHARGE AIR
= SUPPLY AIR
= OUTDOOR AIR
VALLOX 252 M-L
= OUTDOOR AIR
= SUPPLY AIR
= DISCHARGE AIR
= EXTRACT AIR
Main parts
Optional equipment
12
13
14
1
2
3
5
6
7
8
9
10
10
4
11
Post-heating unit
• water operated or electrical
Preheater
• electrical
Pressure difference switch unit
187
22
0
222
1100
187
222
282
1370
22
0
(Door and insulation 55 mm)
Ø2
50
4
Pcs.l
61
0 +
*
14
6
1
4
5
8
12
10
11
7
13
3
9
2
A
B
C
D
Supply air fans
Discharge air fans
Heat recovery cells
Heat recovery bypass
Supply air filter EU7
Discharge air filter EU5
Discharge air filter EU3
Outdoor air filter EU3
Condensing water reservoir
Condensing water outlet
Electrical connection lead-throughs
A
B
C
D
A
B
C
D
Internal
outlet collar
* detachable inner coupling
