VALLOX DIGIT2 SE
7
INSTRUCTIONS FOR USE
© VALLOX • We reserve the right to make changes without prior notice.
Remember!
Switch post-heating off when it starts
to get too warm in the dwelling becau-
se of warm weathers.
Switch post-heating on again when it
gets cooler in autumn.
2.12. Heat recovery antifrost function and preheating
• Antifrost prevents the heat recovery cell from freezing, thus ensuring proper ventilation even in
cold periods.
• According to the factory setting antifrost is implemented in units with an electric preheating
radiator by stopping the supply air fan. The stopping function is controlled on the basis of the
data given by the temperature sensor measuring the temperature sensor of exhaust air after
the heat recovery cell.
• T he supply air fan stops when exhaust air temperature falls to the setpoint (factory setting
+4
°
C) and starts when exhaust air temperature has risen to the value set (by the amount of the
hysteresis setting, factory s3
°
C).
Preheating
• The unit is equipped either with an electric preheating radiator or a liquid-circulating
preheating radiator (MLV model). The purpose of using the radiator is to minimise momentary
stopping of the supply air fan. This ensures a maximally even supply air flow through the unit.
• An electric preheating radiator is taken into use by using the Settings menu, adjusting switch-
on temperature to be higher than the value for “supply fan Stop”. The difference could be
2
°
C, for example.The radiator switches on when exhaust air temperature falls to the setpoint
and switches off when exhaust air temperature has risen to the value set (by the amount of the
hysteresis setting, factory s3
°
C).
If radiator power is not sufficient in extreme conditions, the supply fan starts to stop as exhaust
air temperature goes down to the “supply fan Stop” value. The setpoint for preheating could
be +6
°
C, for instance; the factory setting for “fan Stop” is +4
°
C.
• The liquid-circulating preheating radiator (MLV model) starts when post-heating has been
switched on and outdoor air temperature is below the preheating setpoint. The setpoint
temperature must be lower than the temperature of the liquid in the ground collector (factory
s0
°
C). The automatic control system of the unit switches on the circulation pump and
opens the solenoid valve of the radiator (see the Technical specification).
2.13. Maintenance reminder
• The maintenance reminder switches on the maintenance reminder symbol ( ) in the main
display of the control panel at defined intervals, the factory setting being 4 months.
• The maintenance reminder symbol is reset at the control panel (see the instructions for using
the control panel, Section 3.3.10.).
• The interval can be set between 1 and 15 months at the control panel.
2.14. Filter guard function
• If DIGIT2 SE is equipped with a pressure difference switch for the supply and/or extract air
ductwork, the switch monitors the pressure difference in the whole ductwork. When pressure
has risen (e.g. because of a clogged filter), the filter guard symbol ( ) in the main display of
the control panel is lit up.
• The filter guard closes the contacts of the fault signal relay, and the filter guard symbol ( ) is
seen in the main display.
• The maintenance reminder is on even during this function.
• The operation threshold for the pressure difference switch is adjusted at the pressure
difference switch regulator (0...500 Pa). Factory setting is ca. 260 Pa, and the setting can be
changed if needed. With clean filters, the symbol should light up at speeds 7 and 8.
2.15. Antifreeze function in water-circulating post-heating unit
• The antifreeze function aims at preventing a water-circulating post-heating unit from freezing.
The automatic function stops the supply and extract air fans as soon as outdoor air
temperature falls below 0
°
C and supply air temperature below +7
°
C. At the same time, the
self-actuated dampers of the fans close and the control valve becomes wide open. The control
panel displays the fault message FREEZING ALERT, irrespective of display.
• The fans start automatically and the dampers open as soon as supply air temperature exceeds
10
°
C.
Pressure difference switch
