Purchased this during a kitchen remodel when we determined that we needed a make-up air duct. We had purchased a Thermador Hood for our kitchen when we realized it likely was going to pull out to negative pressure in the home. This has worked great with the pressure switch that automatically opens the damper when the pressure builds in duct. Only had a problem with the pressure sensor on install, found out quickly from tech support that it can only be mounted upright, we had not. When I corrected that, it functioned as it was supposed to.

Found a single MD10TU and 10 inch duct without a fan behind it insufficient to adequately compensate for an 800 CMF vent fan. The damper stays in the open, (powered) position with the vent fan off with no back draft issue present. A replacement pressure switch in on the way.