NIBE FLM 40 4xG4 Filter set (Multipack)

✅ Filter Maintenance Recommendations

⏳ When to Replace Filters?

• Filter contamination is monitored by a timer in the control unit. Replacement alerts appear on the display or in the mobile app.
• ⚠️ A filter alert is just a reminder — your AHU will continue operating normally.
• The replacement frequency depends on outdoor air quality. If you live near busy roads, gravel paths, construction sites, industrial zones, or farmland, you may need to replace filters 1.5–2× more often.
• Most manufacturers recommend replacing filters at least twice a year: before and after the heating season.

⚙️ Recommended Filter Replacement Intervals:

Using a G4 prefilter can extend F7–F9 filter lifespan by 2–3 months.

Return air filters (extract side) may be replaced less frequently than supply air filters (F7, F7/AC).

♻️ Reusable Filter Types

• Wire-frame filters and filter media pads (cut-to-size materials) can be vacuumed every 2–3 months, up to 2–3 times before replacement — if permitted in your unit's manual.
• However, panel and pocket filters are strictly single-use. Vacuuming or washing them may damage the filter and reduce efficiency. Fine dust gets trapped in the inner layers and cannot be removed.

⚙️ Step-by-Step Filter Replacement

1. Check your user manual if replacing filters for the first time.
2. Turn off the AHU and wait until all fans stop rotating.
3. Remove the front panel or filter cover.
4. Take out the old filters.
5. Vacuum inside the unit if possible and wipe down filter holders with a damp cloth.
6. Inspect and clean other AHU components if needed — such as rotor belt, heat exchanger, fan blades, etc.
7. Install new filters carefully:
   • Check airflow direction — arrows on the filters must match the AHU’s airflow.
   • Typically, filters are installed before the heat exchanger; arrows should point inward toward the center.
   • If there are 3 filters and the F7/F8 filter is on the opposite side of the exchanger from G4, its arrow must point away from the exchanger.
   • Incorrect orientation can increase airflow resistance by up to 15%.
8. If using different filter types (e.g. F7 and G4), install F7 on the outdoor air side and G4 on the extract side. The outdoor air duct is usually insulated; the extract duct is not. Refer to the manual and note whether your unit is left- or right-handed.
9. After installation, close the cover and restart the unit.
10. Reset the filter timer using the control device, according to the user manual.

❌ Do Not Use the Unit Without Filters

Running your ventilation unit without filters will clog the heat exchanger and contaminate the entire system. It will also void your warranty.

⏳ Why Timely Filter Replacement Matters

Dirty filters increase airflow resistance, reduce airflow, raise energy consumption, and increase operating noise. Replacing them on time ensures efficiency and extends system life.

Watch the instructional video on general filter replacement: