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VALLOX 252 D

10

PRESSURE DIFFERENT SWITCH

Setting the pressure difference switch

You can test the function of the factory set pressure difference switch and, if
needed, adjust it as follows:

1.

Turn the ventilation unit on and adjust ventilation capacity according
to the planned volume. Note! The doors of the ventilation unit have to
be mounted.

2.

If the filter guard symbol ( ) does not appear in the main display of the
control panel, follow the steps 3...5. If the symbol appears, proceed to
step 6.

3.

If you want to test the pressure difference switch of the supply air
ductwork, cover about half of the supply air filter (EU7) with a piece of
cardboard. If you want to test the pressure difference switch of the
extract air ductwork, cover about half of the extract air filter (EU5).

4.

Restart the ventilation unit and adjust ventilation capacity according to
planned air volumes. Note! The doors of the ventilation unit have to be
mounted.

5.

If the filter guard symbol appears in the main display of the control
panel, proceed to step 7. If it does not appear, proceed to step 6.

6.

You can increase the setpoint of the pressure difference switch as
follows:

Disconnect VALLOX 252 D from the network by switching off power supply on the
distribution panel, for instance.

• Remove the doors of the unit (upper door first).

• Remove the bottom cover of the electrical connection box inside

the unit.

• Remove the cover of the pressure difference switch and turn the

adjusting wheel, increasing the setpoint (see the adjoining picture).

• Put the covers and the door in place, restart VALLOX and adjust

ventilation capacity according to planned air volumes.

• Proceed to step 2.

7.

The pressure difference switch unit is now adjusted: if pressure
difference in the ductwork increases (e.g. clogged filter or grate), the
filter guard symbol ( ) lights up in the main display of the control panel
and the points of the fault signal relay close.

Note! Remove any filter covers used during the adjustment!

Summary of Contents for 252 D Series

Page 1: ...0 W 1 A 2x230 W 1 A Fans Heat recovery Heat recovery bypass Preheater Electric post heating unit Water circulated post heating unit Filters Filters Manual control DIGIT control panel CO2 and RH contro...

Page 2: ...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 defrostin...

Page 3: ...djusts fan speed so as to keep the carbon dioxide content in the ventilation zone below the setpoint If two or more sensors are used fan speed is adjusted in accordance with the highest measuring resu...

Page 4: ...0 25 C The factory setting is 10 C Heat recovery cell defrosting function The defrosting function prevents the heat recovery cell from freezing thereby ensuring that ventilation works in cold periods...

Page 5: ...setpoint and the actual temperature For instance if indoor air temperature is 25 C and the setpoint is 24 C the aim is to blow 23 C air to the ventilation zone If the temperature in the ventilation zo...

Page 6: ...tings menu press the and buttons simultaneously In the settings menu you can change setpoints for the ventilation unit The content display shows humidity and carbon dioxide content The corresponding s...

Page 7: ...he control panel is changed with the and buttons Two control panels cannot have the same address If control panels have the same address they will go to the bus fault state and will not operate The de...

Page 8: ...may cause a faulty post heating function 1 3 17 Choosing post heating for the unit Radiator type electric rad Automatic or manual search of the basic humidity level The selection is done with the and...

Page 9: ...1 3 22 Changing the setpoint for carbon dioxide adjustment CO2 setting 0900 PPM Basic fan speed 1 Maximum fan speed 8 Carbon dioxide adjustment CO2 900 ppm CO2 Basic humidity level value chosen eithe...

Page 10: ...he doors of the ventilation unit have to be mounted 5 If the filter guard symbol appears in the main display of the control panel proceed to step 7 If it does not appear proceed to step 6 6 You can in...

Page 11: ...is not functioning The extract air filter or the cell is clogged The initial adjustments for ventilation have not been made 1 Check the insulation of the attic ducts If the heat recovery cell has fro...

Page 12: ...e but they can be cleaned with pressure air carefully blowing against the direction of contamination When needed replace the filters with new ones The recommended interval for filter change is one yea...

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