50MAINTENANCE BEFORE BEGINNINGMAINTENANCE WORKThe safety switch automatically turns off the power whenthe upper door of the unit is opened.WARNINGAlways disconnect the power plug before starting theventilation unit maintenance.Opening and closing the doors1. Lift the latches to open the upper door of theventilation unit.2. Lift the upper door off.CAUTIONThe door is heavy.3. Open the lower door of the ventilation unit byundoing the finger screws.4. Lift the lower door off.5. Close the doors in reverse order.There are two unit models, left- (L) and right-handed (R).The figure shows the right-handed model.REPLACING THE FILTERS (USER)When the maintenance reminder becomes activated,check the cleanliness of the filters and replace them ifrequired.The Vallox ventilation unit has three air filters:• Class G4 coarse filter filters insects, heavy pollenand other relatively large foreign objects out of theoutdoor air.• Class F7 fine filter filters microscopic pollen and dustparticles out of the supply air.• Class G4 coarse filter filters the extract air and keepsthe heat recovery cell clean.The filter replacement interval depends on the ambientdust concentration. It is recommended that the filters bereplaced every spring and autumn, or at the very leastonce a year.NOTEUsing original Vallox filters ensures that the ventilationunit remains in top condition, giving the best results.