Cleaning of ventilation ducts in ventilation systems

I think the pipes in our kitchen look similar. Of course, theoretically, the mixing of air from the supply and exhaust ducts should not occur. But 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 could not tell me how long it will last. I can already imagine that leaks in the heat exchanger or in the system could cause 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 the air can simply be drawn back. We moved in 3 years ago and I will definitely have the ventilation pipes cleaned before the 5-year warranty expires. Who knows what you might find in pipes.

Moreover, at least in my case, the outlets of the supply and exhaust air ducts are not far apart and the air can easily be drawn back.

What, what? Exhaust air is hardly sucked from the supply air, right? If supply air is sucked from the exhaust air, that is ultimately the purpose of the system...

I am no longer surprised that the exhaust air pipes look so dirty. When you work without filters on the exhaust air valves...

Wow, two brand new members show up and encourage the OP. Nightingale...

The exhaust pipe looks like in the pictures only if the exhaust filters were "forgotten."

Exhaust air cannot be sucked into the supply air because the supply air does not suck in but blows out...

Enough with the nonsense already.

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

Oh man, this is ridiculous. probably couldn’t sleep last night and created 2 accounts. I reported it.

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, since there are recommendations from DIN and VDI as well as maintenance contracts.

I also cannot believe that the pipes can be cleaned with a cleaning reel including a brush and a dust trap or with a ball that is sucked through the pipe. The pipes are far too long and it involves fine dust.

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

Here is a before/after picture:


Cleaning tool:

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

It does not occur in practice either, at least not in a common cross-/enthalpy heat exchanger.

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 your doubts come from? What material is the heat exchanger made of?

I can already imagine that leaks in the heat exchanger or the system could cause germs from the exhaust duct to enter the supply duct.

That is simply physically impossible. Here is a schematic of a crossflow heat exchanger:



As you can see, only energy transfer is possible. Otherwise, the design would contradict itself.

Furthermore, at least in my case, the outlets of the supply and exhaust ducts are not far apart, and the air can easily be drawn back.

All the better, so any dust (if there is any) will be transported away directly before it reaches your lungs.

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 find inside the pipes.

If you do not live on a busy street, there should only be a light film of dust in the entire system after 5 years.

Regarding the OP and others, Alex85 has already said everything. No filters, no smooth pipes. So errors were made already in the planning, execution, and operation of the system. No wonder cleaning is necessary.

P.S.

This is what the impellers of my system look like after 3 years of continuous operation. IMHO this is absolutely harmless. Below=exhaust air Above=supply air