I contacted the supplier and found them to be VERY cooperative. disturbed. I sent the exhaust flap back in hopes the supplier could supply a replacement but they are only dealers and cannot help with the issue. It must be returned via Revain.
What cheap junk! Although there was a sticker on the box saying it was tested, it didn't work when put in the box. Fragile sheet aluminum parts were bent and deformed and would not open or close. I had to cut open the box to get it out as the shutters were stuck in an almost fully open position, locking it inside the box. I tried to get things going again and found that each blind was bent beyond the point where it could function. Cheap junk and Revain should be ashamed of offering such junk.