Controlled residential ventilation / DIBT stove / pressure monitor

Hello,
now I want to report how things turned out for us.
As written on 29.8., I have a single-family house from 53, with controlled residential ventilation and a room air-independent stove. The chimney sweep insisted on a pressure monitor or proof that no more than 8Pa negative pressure would occur in the house.

The proof was neither available from the manufacturer, nor from the planner or installer. They also suggest a pressure monitor.
The chimney sweep then reported the defect to the building authority.

In the end, we agreed with the chimney sweep on a pressure comparison measurement during regular operation.
The pressure difference was measured between outside air and the air in the stove installation room. That day it was quite windy and the pressure fluctuated by about 4Pa. No difference was detected whether the ventilation system was off, running at normal or full fan stage. With this, the chimney sweep’s conditions were met.
Additionally, I wanted a measurement with blocked supply air at full fan stage (worst case). Here the negative pressure in the room increased by about 2Pa, so a maximum of 5Pa was reached. Of course, one must say that although my house was extensively modernized, it does not reach the airtightness of a passive house.

Conclusion:
My RLU stove was approved without a pressure monitor.
The pressure test cost 250 euros.
For my safety, I hung up a CO alarm. It costs 50 euros, runs on battery, and must be completely replaced every 6 years. I claim it is safer and more reliable than a pressure monitor.

Regards
Michael

Hello, now I want to report how it turned out with us. ... We finally agreed with the chimney sweep on a pressure comparison measurement during normal operation. ...

Conclusion: My RLU stove was approved without a pressure monitor. The pressure test cost 250 euros. For my safety, I hung up a CO alarm. It costs 50 euros, runs on battery, and must be completely replaced every 6 years. I claim it is safer and more reliable than a pressure monitor.

Regards Michael

Hello Michael,

I would be interested in a few details about the pressure comparison measurement. Who carries it out? The measurement was certainly done before the installation of the stove? Was there an agreement with the chimney sweep up to what value he accepts the installation without a pressure monitor? I am thinking of a safety draft.

Best regards, Ulf

Hello Ulf, the pressure comparison measurement was carried out by a civil engineer who specializes in Blower Door tests. Local companies can easily be found on the internet. The measurement was conducted after the installation of the stove. The chimney sweep insisted that the stove be burning during the measurement. We conducted measurements before and after firing up and could not detect any difference. That is clear since the stove is room air-independent and we measured the pressure difference between indoor and outdoor air. The chimney sweep accepted a value up to 8Pa, which is the test pressure for RLU stoves. There was no mention of a safety exhaust; we did not even have to check failure scenarios such as fan failure, clogged filter, etc. Similarly, a stove door that is not properly closed or a defective seal is not taken into account. With a properly functioning controlled residential ventilation system, supply air and exhaust air are equal, so no pressure difference arises. Only when the supply air fails does a negative pressure build up. We simulated that. In our case, the negative pressure increased only slightly. I think in a passive house the 8Pa limit will then be exceeded. On the other hand, 8Pa can also be reached without a ventilation system just by the wind. Regards Michael

Thank you for the information.

The situation is somewhat different for us, as we live in a new building (Kfw70). The controlled residential ventilation also works with decentralized supply air (meaning holes in the walls) and a central fan for the exhaust air. Therefore, a slight negative pressure is created in our case due to the principle. However, the supply air valves cannot be hermetically sealed, so air can always flow in.

But I will discuss this with the chimney sweep...

Best regards Ulf

Yes, I have news - the fireplace is about to be installed, the district chimney sweep "doesn't need" a pressure switch because the stove is certified. However, the power cable has already been laid and is now fiddling around the chimney

Hello Yvonne, did you have a controlled residential ventilation system installed?

Hello Yvonne, did you have a controlled residential ventilation system installed?

Yes, certainly