ᐅ Mechanical ventilation duct – screws protruding inside the duct!!!

Hello everyone,

I had a house built through a developer. A mechanical ventilation system with heat recovery was integrated into the insulation layer. The ventilation ducts are made of galvanized steel in rectangular duct design.

After the house was completed, I wanted to vacuum the ducts because a lot of dust had accumulated. I found that at every joint between two ducts, several screws protrude into the ventilation duct. This makes it almost impossible to insert the vacuum hose, and I almost couldn’t pull it back out.

According to the company that installed the system, fastening rectangular ducts/ventilation pipes with self-drilling screws is standard practice and allowed.

In my opinion, this makes it impossible to properly clean the ducts, which I consider a serious defect.

Are there any regulations, standards, or guidelines on this?

Has anyone experienced a similar problem?

Thank you very much for your help.

Thomas.

Hello Thomas,

el_curioso schrieb:

A controlled residential ventilation system with heat recovery was integrated into the insulation layer. The ventilation ducts are made of galvanized steel in rectangular duct design.

Which manufacturer was installed? Unless it is a rather unknown brand, they should be able to provide you with reliable information.

Regards, Bauexperte

The mechanical ventilation system is a Vallox Plus350. However, the ducts were not installed by the manufacturer because the floor construction was too shallow, so flatter rectangular spiral ducts were used instead.
I have already contacted Vallox / Heinemann about this, but have not received any response so far, and no one was able to assist me by phone either.

Regards,
Thomas.

Do the ducts really need to be cleaned regularly? For the exhaust air, it doesn’t really matter since it goes outside anyway. For the supply air, you usually only have residual construction debris in the ducts (why would something get in there? Normally, the openings are sealed until connection to the system, so the ducts stay clean – that was the case for us). Fresh air flows through the filters in the system.

Well, I have asked myself that question too—whether I will ever actually need to get to it. But from what I’ve read online, it is recommended to clean the pipes every few years. And knowing my wife, if there’s ever a spider, spider web, or anything moving inside, the vacuum cleaner will definitely be used.

The pipe sections need to be fixed together somehow because otherwise there is a high risk that they will be pulled apart during the work (such as during backfilling or screeding).
Yes, the pipe systems should be cleaned regularly, especially on the exhaust side, because with the low air speeds used (higher speeds would cause noise issues), deposits can form and eventually clog the pipes. For round systems, a suitable “cleaning ball” is usually suctioned through to remove buildup.
In the system I installed, the pipes stay in place thanks to the seals on the connectors, and immediately after that, they are secured with a nail strip. This way, there are no screws protruding inside the smaller pipes.
For the larger round ducts, like in the Lindab “Safe” system, instructions specify that depending on the diameter, a certain number of screws or rivets must be used to secure the pipes.
I doubt that the “cleaning” you mentioned can be done effectively with a vacuum cleaner; it’s more about specialized companies that carry out this type of cleaning.