VALLOX 252 D
9
DESCRIPTION OF OPERATION VALLOX 252 D VKL, with water radiator
Control of operation
Power supply can be controlled via the contactor in the distribution panel,
using a timer program, for instance. Upon starting, the ventilation unit
uses minimum power, and after that power is controlled on the basis of
measurement data given by air quality sensors and/or through manual
control on the control panel.
Fan speed adjustment
Manual control
Fan speed of the ventilation unit is controlled in 8 steps on the control
panel (
H
).
Carbon dioxide and humidity control
The fan capacity of the ventilation unit is controlled in multiple steps de-
pending on load, based on the measuring results of the
CO
2
and
RH
sen-
sors located in the ventilation zone. The aim is to keep the CO
2
and /or
humidity content of the zone below the setpoint that has been defined on
the control panel
H
. One or more modes of regulation can be used at the
same time. The dominant mode is the one demanding boosting. Ventila-
tion can be adjusted in a maximum of 8 steps. The basic and maximum
fan speeds can be set at the desired level on the control panel
H
.
Voltage and current signal control
The fan capacity of the ventilation unit is controlled in 8 steps with the
voltage signal 0…10 VDC, or with the current signal 0…20 mA. How-
ever, fan capacity cannot be set above the preset maximum fan speed
when automatic adjustments are active. The voltage or current signal con-
trol is used to control basic fan speed. Because of this, fan speed can only
be raised, but not lowered by the manual, CO
2
and %RH controls.
Supply air temperature
Supply air temperature can be controlled using either constant temperatu-
re adjustment or cascade adjustment.
Supply air constant temperature control
The control unit directs the operation of the control valve (
SV
) on the basis
of the measuring data on the temperature sensor
TE2
. The aim is to keep
supply air temperature at the temperature value set on the control panel
H
(+10…+30˚C).
Supply air cascade control
The control unit directs the operation of the control valve
(SV)
on the basis
of the measuring data on the extract air sensor
TE4
. The aim is to keep
extract air temperature at the temperature value set on the control panel
H
(+10…+30˚C).
Heat recovery bypass
When post-heating has been switched on, heat recovery is enabled all
the time. Automatic heat recovery bypass is active whenever post-heating
has been switched off and outdoor temperature exceeds the preset
threshold (range 0˚…+25˚C). In this case, the control unit directs the
operation of the damper motor (
FG
) on the basis of measuring results given
by the outdoor sensor
TE3
and the extract air temperature sensor
TE4
. The
aim is to get as cool supply air to the ventilation zone as possible.
However, heat recovery is in use whenever outdoor air goes below the
preset threshold.
Heat recovery anti-freezing
The control / adjustment center of the unit directs the operation of the
preheater (
LP1
) on the basis of the measurement data supplied by the
temperature sensor
TE1
. The aim is to prevent the risk of freezing and the
stopping of the supply air fan (
TF
). If the capacity of the preheater (
LP1
) is
not sufficient, or if there is no preheater, the control center intermittently
stops the
TF
supply air fan on the basis of the measuring data on the
temperature sensor
TE1
, thereby preventing the heat recovery cell from
freezing. As soon as the risk of frosting passes, the fan restarts
automatically. The threshold temperature for defrosting (-6…+15˚C) and
the difference area (+1…+10˚C) can be set on the control panel (
H
).
Overheating protection of the heating unit
The overheat protection thermostats
TZ1
and
TZ2
monitor the surface
temperature in the
LP1
heating unit. The indication of a freezing risk
appears in the display of the control panel. The
TZ1
overheating protector
is reset automatically, and the
TZ2
protector manually.
Antifreeze protection of the water radiator
On the basis of the measuring data of the outdoor air temperature sensor
TE3
(outdoor air < 0 ˚C) and of the supply air temperature sensor
TE2
(supply air < 7 ˚C), the control / adjustment center of the unit stops the
TF
and
PF
fans. This is done in order to prevent the freezing of the water
radiator
LP2
. The indication of a freezing risk ("Freezing alert) appears in
the display of the control panel. The fans automatically restart as soon as
the risk of freezing has passed (supply air > 10˚C).
Alarms
The pressure difference switches
PDS1
and
PDS2
monitor the pressure
difference between the supply and extract air sides. If the pressure
difference rises too high because of dirty filters or clogged ducts, an
alarm will be issued, showing as a symbol ( ) in the main display of the
control panel. If the unit is not equipped with pressure difference switches,
the symbol ( ) appearing in the main display of the control panel reminds
of the need of servicing the unit. The reminder interval can be set between
1...15 months. The factory setting is 4 months. This function is always
active. The fault signal relay in the unit gives potential-free alarm
indications on the following fault conditions:
• During water radiator anti-freezing, the relay points close and open at
10-second intervals.
• An alarm of high carbon dioxide content (>5000 ppm) switches on the
relay at 1-second intervals.
• In other fault situations, such as sensor faults and filter guard ( ) alarms,
the points of the relay close.
Booster or fireplace switch function
An extra switch
S
may be connected to the connection box of the
ventilation unit to work as a booster or fireplace switch. The operation of
the switch is selected on the control panel
H
. The booster switch function
raises fan speed to the preset maximum speed for 45 minutes.
The fireplace switch function stops the extract air fan for 15 minutes, and
causes overpressure in the ventilation zone.
LON remote monitoring control can be implemented with the VALLOX LON converter.
Voltage values for fan speeds:
0
(0.20...1.25 VDC)
1
(1.75...2.25 VDC)
2 (2.75...3.25
VDC)
3 (3.75...4.25
VDC)
4 (4.75...5.25
VDC)
5 (5.75...6.25
VDC)
6 (6.75...7.25
VDC)
7
(7.75...8.25 VDC)
8 (8.75...10.00
VDC)
Current signal values for fan speeds:
0 (0.5...2.5 mA)
1
(3.5...4.5 mA)
2
(5.5...6.5 mA)
3 (7.5...8.5 mA)
4 (9.5...10.5 mA)
5 (11.5...12.5 mA)
6 (13.5...14.5 mA)
7 (15.5..16.5 mA)
8 (17.5...20.0
mA)
Voltage and current signals
Code
Name
Technical details
Note!
Equipment
(factory settings in parentheses)
Parts list
CO
2
CO
2
sensor, max. 5 pcs
Adjustment range 500...2000 ppm (900)
Option
Carbon dioxide control
Adjustment interval 1...15 min. (1)
FG
Damper motor
Automatic heat recovery bypass 24 V, 2 W, 8 Nm Standard
X
H
Control panel, max. 3 pcs
Setting, operation, display
Standard, 1 pc
X
S
Booster / fireplace switch
Functions as either a booster or
Standard
X
a fireplace switch (booster switch)
LON
LON converter
Remote monitoring control
Option
LP1
Preheater
Electric radiator 2.5 kW
Option
LP2
Post-heating unit
Water radiator 5kW, 70/50˚C
Option
HRC1
Heat recovery cells
2-step, h = 70 %
Standard
X
HRC2
PDS1
Pressure difference switch
Adjustment range 0...500 Pa (420)
Option
Pressure guard for supply air
PDS2
Pressure difference switch
Adjustment range 0...500 Pa (420)
Option
Pressure guard for extract air
PF
Extract air fan
qv = 230 dm
3
/s (100 Pa)
Standard
X
%RH
Humidity sensor, max. 2 pcs
Adjustment range 1...99 % (50)
Option
Humidity control
Adjustment interval 1...15 min. (1)
SU
Filter
Supply air EU7, extract air EU5
Standard
X
SV
Actuator valve unit
230 V, open when dead
Option
TE1
Temperature sensor
Exhaust air temperature
Standard
X
Heat recovery defrosting
Adjustment range -6...+15˚C (HRC)
preheating control
Adjustment range -6...+15˚C (preheating)
TE2
Temperature sensor
Supply air temperature
Standard
X
TE3
Temperature sensor
Outdoor air temperature
Standard
X
TE4
Temperature sensor
Extract air temperature
Standard
X
TF
Supply air fan
qv = 230 dm
3
/s (100Pa)
Standard
X
TZ1
Overheating protector
Automatic reset (+90˚C)
Included
of the electric radiator
Self-resetting
in LP1
TZ2
Overheating protector
Manual reset (+95˚C)
Included
of the electric radiator
in LP1
