Control of operation
Power supply to the unit can be controlled with a contactor in the distribution panel if nee-
ded, e.g. with a timer programme. After starting, the unit first operates at basic fan speed.
After that power is adjusted based either on the measurement data received from air quality
sensors and/or on manual control at the control panel.
Fan speed adjustment
Manual control
Fan speed of the ventilation unit is controlled in 8 steps at control panel
H
.
Week clock control
Fan speed of the ventilation unit is controlled in 8 steps using the week clock in control panel
H
. The week clock can be used to programme the desired fan power option for each hour in
the day.
Carbon dioxide and humidity control
The fan power of the ventilation unit is controlled in multiple steps depending on loads, and
based on the measurement results of the air quality sensors (CO
2
and %RH sensors) located
in the ventilation zone. The aim is to keep carbon dioxide and/or humidity content below
the threshold set at control panel
H
. It is also possible to select an automatic search for the
humidity content setpoint at the control panel. One or more modes of control may be used
simultaneously. The dominant mode is the one demanding boosting. Fan speed varies de-
pending on load status between the basic and maximum fan speeds. The basic and maxi-
mum fan speeds can be set at the desired level at control panel
H
.
Control through voltage or current signal
The fan power of the ventilation unit is controlled in 8 steps with a voltage signal of 0…10
VDC, or with a current signal of 0…20 mA. However, fan power cannot be raised above the
set maximum fan speed.
Voltage or current signal control is used to control basic fan speed. Because of this, it is
possible to raise fan speed with the manual, CO
2
and %RH controls when needed, but not to
lower it.
Supply air temperature
Supply air temperature can be controlled with either constant temperature control or casca-
de control.
Supply air constant temperature control
The control unit directs the operation of post-heating unit
LP2
on the basis of the measuring
data given by by supply air temperature sensor
TE2
, aiming at keeping supply air tempe-
rature at the temperature value set at control panel
H
(+10…+30 ˚C).
Supply air cascade control
The control unit directs the operation of post-heating unit
LP2
on the basis of the measure-
ment data given by extract air temperature sensor
TE1
, aiming at keeping extract air tem-
perature at the temperature value set on control panel
H
(+10…+30 ˚C).
Heat recovery bypass
Heat recovery is enabled whenever post-heating has been switched on. Automatic heat reco-
very bypass is active whenever post-heating has been switched off and outdoor temperature
exceeds the setpoint (to be set between 0…+25 ˚C). In this case, the control unit directs the
operation of damper motor
FG
on the basis of measuring results given by outdoor sensor
TE3
and extract air temperature sensor
TE1
. The aim is to get as cool supply air to the
ventilation zone as possible. However, heat recovery is always active when outdoor air tem-
perature is below the setpoint.
Heat recovery defrosting
Active when outdoor temperature is less than 0 ˚C. The control centre of the unit controls the
operation of preheating unit
LP1
on the basis of the measurement data of exhaust air
temperature sensor
TE4
, preventing freezing alerts and the stopping of supply air fan
SF
. If
the power of preheating unit
LP1
is not sufficient, the control centre keeps stopping supply
air fan
SF
on the basis of the measurement data of exhaust air temperature sensor
TE4
, thus
preventing the
HR
cell from freezing. As soon as the risk passes, the fan restarts automatical-
ly. The threshold temperature (–6...+15 ˚C) and the difference area (1...10 ˚C) for defrosting
can be set at control panel
H
. When the
SF
fan stops, power supply from preheating unit
LP1
is stopped and post-heating radiator
LP2
continues to heat.
Overheating protection of heating unit
Overheating protection thermostats
TZ1
and
TZ2
monitor the surface temperature of hea-
ting units
LP1
and
LP2
. If surface temperature exceeds the threshold, overheat protection is
triggered and power supply to the heating unit is stopped. Overheat protector
TZ1
is reset
automatically and
TZ2
manually.
Alarms
Pressure difference switches
PDS1
and
PDS2
monitor the pressure difference between the
supply and extract air sides. If the pressure difference rises too high, an alarm will be issued.
This is indicated by 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:
• alarm of high carbon dioxide content (> 5000 ppm ) switches the relay at 1-second inter-
vals. The fans stop. This is acknowledged by switching off the unit.
• in other fault situations, such as a sensor fault and a filter guard alarm ( ), the points of
the relay close.
Booster or fireplace switch function
The booster or fireplace switch function of the unit is controlled either at control panel
H
and/or separate switch
S
, which can be connected to the connection box of the unit. The mode
of switch operation is selected at control panel
H
.
The booster switch function raises fan speed to the set maximum speed for 45 minutes. The
fireplace switch stops the extract air fan for 15 minutes and produces overpressure in the
ventilation zone.
LON
remote monitoring control can be implemented with a
VALLOX LON
converter.
VALLOX 280
DESCRIPTION OF OPERATION, electric post-heating unit
11
© VALLOX • We reserve the right to make changes without prior notification.
PARTS LIST VALLOX 280, electric post-heating unit
Code
Name
Technical data
Standard /
(factory settings in parentheses)
Option
Voltage and current signal values (selection in the motherboard)
Voltage values for each fan speed:
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 values for each fan speed:
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
CO2
Carbon dioxide sensor, 5 at most
Adjustment range 500...2000 ppm (900) Option
Carbon dioxide control
Adjustment interval 1...15 min. (10)
FG
Damper motor
HR bypass automation, 24 V, 2 W, 8 Nm Standard
H
Control panel, 3 at most
Setting, operation, display, 1 included
standard
S
Booster / fireplace
Either booster or fireplace switch
Standard in
switch function
operation (booster switch)
control panel
LON
LON converter
Remote monitoring control
Option
LP1
Preheating unit
Electric radiator 2.5 kW
Option
LP2
Post-heating unit
Electric radiator 2.5 kW
Option
HR1, HR2 Heat recovery cell
2-step, = 70%
Standard
PDS1
Pressure difference switch
Adjustment range 0...500 Pa
Option
Pressure guard of the supply air filter
PDS2
Pressure difference switch
Adjustment range 0...500 Pa
Option
Pressure guard of the extract air filter
EF
Extract air fan
qv = 290 dm
3
/s (100 Pa)
Standard
%RH
Humidity sensor, 2 at most
Automatic / adjustment range 1...99% Option
Humidity control
Adjustment interval 1...15 min. (10)
G3, F7
Filter
Supply air G3+F7, extract air G3
Standard
F5
Filter
Extract air F5
Option
TE4
Temperature sensor
Exhaust air temperature
Standard
HR cell antifreezing,
Adjustment range -6...+15 ˚C (3)
preheating control
Adjustment range -6...+15 ˚C (5)
TE2
Temperature sensor
Supply air temperature
Standard
TE3
Temperature sensor
Outdoor air temperature
Standard
TE1
Temperature sensor
Extract air temperature
Standard
SF
Supply air fan
qv = 245 dm
3
/s (100 Pa)
Standard
TZ1
Overheating protection
Automatic (+ 60 ˚C), Self-resetting
Included in
of heating unit
LP1/LP2
TZ2
Overheating protection
Manually reset (+95 ˚C)
Included in
of heating unit
LP1/LP2