In the heating season, the extract air humidity condenses to water. In new buildings, condensation runoff can form rapidly. Condensed water must be able to freely leave the unit.
Some condensing water may have accumulated in the bottom pool of the unit; this is normal and requires no corrective action.
At some time before the heating season begins (e.g. during autumn maintenance), check that the condensing water outlets in the bottom pool are not clogged and that there are no leakages. To check this, pour some water into the pool. Clean as required.
Water must at all times be kept out of the electrical system.