ᐅ Supply and exhaust air of the decentralized ventilation system swapped – how to clean?

Merry Christmas first of all.

Now my question:

When replacing the external filters of our central ventilation system with heat recovery for the first time, I unfortunately noticed that the intake and exhaust openings are switched, meaning the filter is actively filtering the exhaust air while the supply air enters the system unfiltered. Can I request a cleaning of the system from the general contractor in addition to the defect correction (they will only replace the "end connectors")? (The system has been running for 6 months now, and in the meantime, roadworks were carried out nearby, so there was definitely a lot of dust in the air.)

First, check how much dirt is in the pipes before you make a big fuss.

But I also suspect that over 6 months a pretty nasty layer of grime has built up inside the pipes...

Since the central systems also have filters for supply and exhaust air inside the unit, nothing should have happened inside the house at all. You can also clean the hopefully relatively short intake pipe yourself. After 6 months, there should hardly be anything inside, even if the street has been worked on, etc.

I believe the general contractor will tell you the same thing, so there’s not much to worry about.

The pipes are not that short; they run beneath the slab towards the outside or inside. The length up to the end piece is approximately 9 meters (30 feet).

So if there is no dirt in the first meter, I assume it won’t get dirty after 9 meters either. Or am I mistaken?

The pipe first goes 2 meters (6.5 feet) straight down; nothing is visible there. I will contact the manufacturer in the new year to ask for their recommendation.