ᐅ Cleaning of ventilation ducts in ventilation systems

I think the ducts in our kitchen look similar. Naturally, mixing the air from the supply and exhaust ducts should not happen in theory. However, I clean my heat exchanger every year (as stated in the manual), and I have my doubts that it will last 5–10 years without damage. Even my heating technician couldn’t tell me how long it will hold up. I can already imagine that leaks in the heat exchanger or the system could allow germs from the exhaust duct to enter the supply duct. Also, at least in my case, the outlets of the supply and exhaust ducts are not far apart, and air can easily be drawn back. We moved in 3 years ago, and I will definitely have the ventilation ducts cleaned before the 5-year warranty expires. Who knows what you might find inside ducts.

bau_2015_ schrieb:
Also, at least in my case, the supply and exhaust duct outlets are not far apart, so the air can easily be drawn back.

What? The exhaust air is hardly being sucked from the supply air, right? If supply air is drawn off at the exhaust, that is ultimately the purpose of the system...

I’m no longer surprised that the exhaust ducts look so dirty. Especially when working without filters at the exhaust vents...

Wow, two brand-new members have appeared and are encouraging the original poster. Nightingale...

The exhaust duct in the pictures only looks that way if the exhaust filters were "forgotten."

Exhaust air cannot be drawn into the supply air because the supply air does not draw in but blows out...

Enough with the nonsense already.

Forgot the filter, didn’t use a smooth pipe... all of that probably exists, but knowingly no one does it that way. Target audience identified.

Oh man, this is ridiculous.
Looks like @Luftikuss couldn’t sleep last night and created 2 accounts. I’ve reported it.

Zuluft schrieb:
Since these are often installed in the ceilings, it is very difficult to clean them.

Not really, and this is done thousands of times daily, not only in Germany, as there are also recommendations from DIN and VDI as well as maintenance contracts.

Zuluft schrieb:
I also can’t believe that you can clean the ducts properly using a cleaning reel with a brush and a dust trap or with a ball that is pulled through the duct. The ducts are way too long, and it involves fine dust.

The length is irrelevant; there are methods that work. Even for much longer ventilation ducts than those typically found in single-family homes.

Here is a before/after picture:

Cleaning tool:

bau_2015_ schrieb:
Of course, mixing of the air from the supply and exhaust ducts theoretically should not occur.

In practice, it doesn’t happen either, at least not in a common cross-flow/enthalpy heat exchanger.

bau_2015_ schrieb:
But I clean my heat exchanger every year (as stated in the manual), and I doubt it will last 5-10 years without damage.

Where do these doubts come from? What material is the heat exchanger made of?

bau_2015_ schrieb:
I can already imagine that leaks in the heat exchanger or the system could allow germs from the exhaust duct to enter the supply air duct.

That is simply physically impossible. Here is a schematic of a cross-flow heat exchanger:

As you can see, only energy transfer is possible. Otherwise, the whole design would be self-contradictory.

bau_2015_ schrieb:
Also, in my case, the outlets of the supply and exhaust ducts are not far apart, and the air could be easily drawn back.

All the better; this way, any dust (if there is any) will be carried away directly before it reaches your lungs.

bau_2015_ schrieb:
We moved in three years ago, and I will definitely have the ventilation ducts cleaned before the 5-year warranty expires. Who knows what you’ll find in the ducts.

If you don't live on a busy street, after five years there should only be a light layer of dust in the entire system.

As for the original poster and others, Alex85 has already said everything. No filters, no smooth ducts. So errors occurred during planning, installation, and operation of the system. It’s no wonder that cleaning is necessary.

P.S.

This is how the impeller wheels of my system look after three years of continuous operation. In my opinion, this is absolutely harmless. Bottom = exhaust air, top = supply air